Most tabs in the properties panel are only displayed if the active object is a certain type. If there is no active object, most of them will be hidden, as you have discovered. It's a bit uncommon to have no active object, but it is possible; deleting all objects in the scene, or creating a new empty scene are two ways. It's also possible to set it in python (bpy.context.scene.objects.active = None), and indeed some addons will (intentionally or otherwise) introduce such a state.

Similarly, not all modifiers can be applied to curve objects. Hence, not all modifiers are available in the drop down while a curve object is selected.


Automatically generate 100 animations, each with a different texture input (BLENDER)

The way I approached this problem in the past, without using Python in Blender, was to create a template .blend file, which uses some texture files it loads, then make a .BAT file which tells blender to render an animation:
"E:\Program Files\Blender Foundation\Blender\blender.exe" -b template.blend -a

Then you can replace the image files using Batch (the language .BAT format uses) with the next setup and render again.
Of course you can also use Python inside Blender:
Change material texture by loading an external .png file with Python
https://docs.blender.org/api/current/bpy.ops.render.html#bpy.ops.render.render


I think you can use Python's exec() or eval() to do this, if the operator is already registered
import bpy
rig_id = "i8fj1rbnfbd76bf5"
op = eval("bpy.ops.pose.rigify_limb_ik2fk_" + rig_id)
# or with exec
# exec("op = bpy.ops.pose.rigify_limb_ik2fk_" + rig_id)

# now you can call op
op(prop_bone='upper_arm_parent.L') # and rest of arguments


How do I reset all of my view panels without having to do the click and drag method?

If you want to come back to the default windows setup you can click on the "+" tab on the top and choose General > Layout (or whatever setup you want to come back to). You can move or delete all this tabs with right click. If you want to save your own custom layout I think you need to create it and Save the Startup File.


How can I make a good looking candle flame effect to be used in Unreal Engine 4

As it seems to be an asset with little significance for details, I'd suggest using a textured plane set as billboard (i.e. always facing the camera).
You can either draw the texture with a few frames of animation or animate the top vertices of the plane, so you get a little bit of flicker. Don't forget to use transparency with your texture.

Obviously, the texture should be set for "emission".


The Light path node allows you to make shaders do different things based on where the incoming light ray was before. When thinking about where "before" is, keep in mind that cycles is a backwards path-tracer.

The Ray Depth output of the light path node gives the number of bounces the ray went through before hitting the lamp (or whatever is using the shader).
So when tracing backwards from the camera to the lamp, surfaces which are directly illuminated (1 bounce away) will hit a lamp with a corresponding strength of 1:

Surfaces illuminated by indirect lighting (2 or more bounces before hitting a light source) will "see" a correspondingly stronger light source:

To see it in action:

As to why it appears "more realistic", I think this really just an artifact of the lamp being way too bright in the first example (it looks fine when the strength in the light falloff node is then set to 1). In fact the setup with the ray depth is less technically realistic, as explained above.

Normally the light falloff node is plugged into the strength, not the color. Then with the default strength of 100 it looks just fine:


Rotate texture at the middle of UV and without tiling distortion (MAX like)

Object coordinate
Object* coordinate has 0 in the middle:

Notice how I apply a 50% scale, because Object coordinate goes from -1 to 1, so it's twice as big as UV coordinate going from 0 to 1)
Offset, then rotate
This is the worst solution. You can subtract .5 from your UV along X and Y, to make the middle have 0, and then add it back after rotating:

Notice how you could use simpler nodes instead of Mapping, like Vector Math > Add, but while we're at it...
Just use "Vector Rotate" node
And precise where is the center - the point around which you rotate:


How to mix material and texture to single mesh?

As far as I know you can only mix textures/materials in one "material".
Try this:

Assigne all verts to "Material.001"
Copy "Material.004" and add it to "Material.001"
UV unwrap your object
Copy nodes (see the image below)
Set "image texture" to clip and to non-color data
Match UV Unwrap to your texture


BGE - How do I make an sound stop when pressing a key, then start again when releasing it?

You need to have the logic in place to disable the original sound.

Rather than using an always sensor to activate the normal sound,use a Nand or Nor controller attached to the original keypress that plays the second sound. If this still doesn't work, activate TRUE and False level triggering which will make the sensor activate (and deactivate, respectively).

These are the two little buttons, each containing 3 dots, on the sensor.


Object floating on heavy sea - how to make shocking rotation less sensitive?

The way I am solving this now is, unfortunately, by baking the action of the floating object (take a smaller baking step interval) and then smoothing the transitions with bezier curve transitions.


How to create a material of horizontal black and white lines

Just a 'Texture Coordinate' node and plug it into a 'Mapping' node. Now you are able to split the output vectors with a 'Separate XYZ' node. If you plug b.e. the 'z'-Value of the 'Separate XYZ' node in the vector of a 'Checker Texture' node, you will get strips along the z-axis, same for the x, y.. with some vector math you can easily manipulate the result


Didn't pay attention to switching to Vertices selection mode, I had Faces mode active, and that is why it didn't work


I'm going to answer by assuming what you are trying to achieve because it isn't really clear.

Add a collection and model your planks inside it.

Outside the collection, add a plane object, then add an array modifier to it. In edit mode scale it along the y axis so that is is about the width of your planks.
Add a particle system to this plane. Set it to "Hair", check "Advanced". Set the number to the number of planks you want to have.
Right click the "Number" field and choose "Copy as new driver". Go back to the array modifier and right click in the "Count" field and choose "Paste Driver". Now you don't need to touch the array modifier again, it will be modified every time you want to add or retrieve planks in the particle settings.

 - Go back to the particle settings. Set the instancer to collection and choose the planks. Uncheck "Show emitter" (twice). Don't forget to check "Pick Random" to add variety. :

Modify it to look like this. You can tweak the "Randomize" fields to add a bit of variety in size and rotation. :

If you add a curve modifier between the array and the particle system, you can even go 3D !


Why Are White Lines Bleeding Between Textured Faces?

This is probably due to MipMapping.

MIP mapping (also sometimes spelled as mipmapping) is a technique where an original high-resolution texture map is scaled and filtered into multiple resolutions within the texture file. MIP maps can be automatically generated from the original texture, but may also be individually painted or adjusted by the texture artist. Typically each subsequent MIP level is half the size of the previous, which guarantees that the complete texture (the original and its MIP maps) is no greater than 1.5 times the original texture.
Each scaled texture, or MIP level, represents what the texture would look like at a specific distance from the users viewpoint. Through the use of filters, the MIP levels give a more natural representation of how colors and details tend to blend together when viewed at a distance.

If your texture has a white default background colour and then some hard edges in your texture -> black road - then through the scaling down when generating MipMaps, the white background colour bleeds into the road. Therefore, always use a margin/padding of 2-4 pixels (depends on the texture resolution) when creating your texture maps. A good description here: http://wiki.polycount.com/wiki/Edge_padding


Manually Painted Vertex Weights don't export to FBX, but auto-weights do

This was due to conflicting vertex groups in the ARP exporter. To fix it, I removed vertex groups that didn't match the secondary controller mode for ARP (which were added in a different bind session set to "none"). In my case, I needed to remove the following groups because my current bind is set to "twist:"
-arm_stretch
-forearm_stretch
-arm_twist
-forearm_twist
-thigh_stretch
-thigh_twist
-leg_stretch
-leg_twist


Texture Atlas Tool message ” Not All Objects Are Visible!”

Just delete the existing UV Group in the menue by pressing the minus button. Create a new one, and do the procedure. For me this worked


The "Clamp To" constraint and the "Track to" constraint can co-exist on the Object Constraints panel.  Place the "Clamp To" above the "Track To", so that the track targeting happens from the newly clamped location.

In this example, the object's location is clamped along a path defined by a Bezier Curve, and its X axis targets an Empty.


What you are seeing is 40 tiles to be rendered. In the posted image the computer was rendering the 23th tile out of 40


Blender cycles CUDA out of memory error in archviz scene

I'm guessing the rug is causing the problem, due to the number of hair particles. If that is the cause, try changing the particle settings or use geometry instead of the hair strands as strand.

Or invest in a better graphics cards, Gtx 1060 with 6 gig of memory works great for my projects.


How do I render specific render layers using python?

Here's a little script, that iterates over all render layers and checks for some condition (e.g. does the layername start with 's'?). Then it disables all render layers and enables one that fulfills the condition until there are no more layers:

import bpy

render_layers = bpy.context.scene.render.layers

for layer in render_layers:

    # some condition
    if layer.name.startswith("s"):

        # disable all
        for l in render_layers:
            l.use = False

        # re-enable a single one that matched the condition
        layer.use = True

        # RENDER HERE


Rigging. Should bones be connected to one big mesh or to many meshes?

This is a matter of personal preference.

If the animation is generated procedurally, it is probably more efficient to make the rocks separate objects. Updating the single transformation of an object is much faster and less memory intense than manipulating a large number of vertices at once.

If the animation animated manually, then there is barely any difference. In Blender, the rig should mainly consist of an armature in which bones control the objects. The individual rocks can patented to the armatures bones or bound to them with a deforming armature modifier. Using the latter, there is no difference between a single or many objects (each with their own armature modifier). The animator is only supposed to interact wuth bones, the objects (less alone individual vertex groups) should be tucked away, so they don't get in the way while animating. The speed difference between a single armature modifier one one object with many vertex groups over many armature modifiers is neglible. Single objects parented to individual bones will have a slight speed advantage in case of a large number of rocks.


The ‘#’ is not part of the variable ‘frame’ but simply indicates to Blender that what you have entered should be interpreted as a Driver. In the case of '#frame' the driver simply returns the value 'frame' - the current frame of animation.
To use the floor function you should prefix the entire expression with '#' - ie, #floor(frame). In order to have the value step up by 1 on each 25th frame you could enter the expression #floor(float(frame)/25). This converts the 'frame' into a floating point value (technically not required - but still good practice), divides by 25 and rounds down to an integer. ie, on frames 0-24 it will produce 0, on frames 25-49 it will produce 1, 50-74 -> 2, 75-99 -> 3, etc.


With very large image resolutions Blender can run out of RAM. The operating system will then start using the hard disk for memory which is slow and will cause low CPU usage (swapping).

To reduce memory usage for very high resolution renders:

Enable Save Buffers in the Performance panel so Blender does not keep the full render in memory during render
Render from the command line so no display buffer must be kept in memory
Output to an OpenEXR file so one tile can be written at a time


Does rotation by exact angle become low-precise in blender?

It seems you have made a slight mathematical error.
The plane has a length of 2 (by default), so if you look at the diagram, the hypotenuse of one of the smaller right triangles is half the length of the plane, so it is $\frac{2}{2} = 1$ unit long.  Now, $\cos(60) = \frac{1}{2}$ so the shorter leg will have length $(1)\cos(60) = (1)\cdot(\frac{1}{2}) = \frac{1}{2}$.  Here is where you made a mistake: $\sin(60) = \frac{\sqrt{3}}{2}$, so the longer leg will have length $(1)\cdot\sin(60) = \frac{\sqrt{3}}{2}$, not $2$.
Since I stink at making mathematical diagrams on paint and that is all I have on my tablet, here is a diagram I drew:


How do I switch to Cycles render engine?

To switch render engines, click the drop down on the header of the info menu at the top of the screen where it currently says Blender Render. You will be presented with 3 options. Blender Render, Blender Game, and Cycles Render. Choose the desired option from there.


How to make outside of camera view darker

The area is called a Passepartout and can be adjusted for each camera.
It's under Camera Tab > Viewport Display


Unless you haven't closed the file and you applied the modifier recently enough (in which case you may be able to Ctrl Z back to it), there is no way to "un-apply" a modifier.

A tool that may work for you though is the un-subdivide tool.  Go into edit mode, selet the entire mesh, hit Space and search for "unsubdivide".


Is it possible to join multiple objects without losing their own UV spaces?

As long as your UV maps have unique names(before joining), they will be kept separate when joined into one mesh. You can change the names of UV maps in the Object Data tab in the Properties Editor:

UV Maps Panel

Multiple UV Maps


How do I override context for bpy.ops.mesh.loopcut?

A custom context needs to be passed as positional argument, not keyword argument.

bpy.ops.mesh.loopcut(override, number_cuts=...,) # not override=override!

Macros follow the same pattern:

bpy.ops.mesh.loopcut_slide(override, MESH_OT_loopcut={"number_cuts": ...,})

What the Macro bpy.ops.mesh.loopcut_slide() specifically needs as context is a 3D View area (Area.type == 'VIEW_3D'), the window region of that 3D View (usually Area.regions[-1]) and the active object to be a mesh and in edit-mode.


Why are there black edges on this textured mesh?

See the paint over I made - your edges are suffering from lack of pixels that are provided in the unwrap. It doesn't matter how big an image you use here if your model faces are only given a few pixels in that image.

If you were to rework that unwrap and allow more equal spacing for the faces in the green area compared to the pink area, you might see less of a problem. A way around this is to use a box mapped image texture to get a nice blended texture and then bake it through an emission shader to a blank image that uses the UV mapping, baking Combined. This way the pixels are arranged nicely on the model surface and then are mapped back to the uv mapping on a new texture to use that isn't showing signs of strain.


How can output of "copy rotation constraint" be accessed?

Use the world matrix.

On Q2 target_object.matrix_world.to_euler() will give you the resulting Euler rot, which could be used in a panel to ans Q1 part.

Example script using the panel template.

import bpy
from math import degrees

class LayoutDemoPanel(bpy.types.Panel):
    """Creates a Panel in the object context of the properties editor"""
    bl_label = "Layout Demo"
    bl_idname = "OBJECT_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    def draw(self, context):
        layout = self.layout
        obj = context.active_object
        col = layout.column()
        mw = obj.matrix_world
        euler_rot = mw.to_euler()
        for axis in "xyz":
            col.label(text="%c : %7.4f" % (axis, degrees(getattr(euler_rot, axis, 0))))

def register():
    bpy.utils.register_class(LayoutDemoPanel)

def unregister():
    bpy.utils.unregister_class(LayoutDemoPanel)

if __name__ == "__main__":
    register()


Why is my final rendered image brighter than the viewport render?

If you have some extra light, turn it off in render in the Outliner or under Object Properties/Visibility:


the cache in physics isnt accessible for simulation

You have to save the file once first, the cache-files will be written in a folder at the same locatation as the saved blend file.


CUDA option not shown when using an old GPU

You are out of luck.

The graphics card in question is quite old and has a Cuda compute capability 1.2, which is not supported in blender anymore

To use GPU rendering in Blender you need a card with a 2.0 compute capability.

Form the manual:

  NVIDIA CUDA is supported for GPU rendering with NVIDIA graphics cards. We support graphics cards starting from GTX 4xx (computing capability 2.0).

read:
How to enable GPU rendering on older Nvidia GPUs?

and
Enabling GPU rendering for Cycles?

Even if you where able to somehow hack GPU rendering with that card, it is likely going to be equal or slower than rendering on CPU.


Why did part of my mesh suddenly turn purple in sculp mode? (Face sets)

In Sculpt mode, Face Sets allows you to create separate areas, a little bit like the Mask except you can create as many face sets as you want and you won't have to mask and unmask to switch from a face set to another, when you'll sculpt on a face set it will only affect this face set until you release the left click and click on another face set.
To paint your face sets you need to press left click. Release and left click again to create a new face set, Ctrl and left click on a face set to extend it, Shift left click to smooth the boundaries. In the Face Sets menu > Init Face Sets you can choose another way to create face sets (for example By UV Seams):

Once you've painted, choose your sculpt brush and enable the Face Sets options:

It looks like once you've painted your face sets you can't enable Dyntopo without deleting the face sets, Dyntopo creates new geometry so it makes sense.
Now sculpt:


head is not moving correctly when I move/rotate the head bone

As I already suspected your head bone is not connected to the neck. Besides that your whole armature is quite messy. There are many other occasions where bones aren't connected to anything (legs, feet) and many of them are redundant (in the image below I tried sorting the bones and moved them away for that purpose. I stopped at the neck ;-) ).

Go check your arm bones, there are layers upon layers of bones that don't serve any purpose.

I would start from scratch and slowly by creating the body armature first and then adding the facial bones to that. A good starting point to learn how to rig a character from scratch is Darrin Lile's tutorial. He knows exactly what he's doing and he also has another rigging tutorial in which he uses rigify.

It's also highly advisable to switch to octahedral and x-ray mode when working with armatures (at least until you know exactly what you are doing). It's way better to keep track of your bones and their connections.


Is there a non-blender API for producing blend files?

I don't know of how to export directly to Blender (seems overly complicated), but you could import PLY/STL/etc files, and then script all the additional features you want.

In my case, I was free to choose the original CAD program, so I chose to build directly in Blender via the PyModule. I work with Blender completely separate from the GUI, and rely only on an external python3 and the bpy module. The bpy module is easy to make.. and you can keep it largely separate from your existing blender install (I run from source folder).

Just run this command (make sure you don't have a $HOME/src):

git clone http://git.blender.org/blender.git && cd blender && git submodule update --init --recursive && git submodule foreach git checkout master && git submodule foreach git pull --rebase origin master && build_files/build_environment/install_deps.sh --with-all --skip-osl && sudo make bpy && cd .. && rm -rf blender && sudo rm -rf build_linux_bpy && rm -rf $HOME/src # this gets bpy python module

I also found this: https://code.google.com/p/pyblenderfile/
but, honestly, I don't see much benefit. Its not developed enough to allow importing everything, so I found a better way of doing the same thing using the bpy module.

What I do is this:

-- build stuff in blender (I do it via python, without ever starting the official application)

import bpy
#build stuff
bpy.ops.wm.save_as_mainfile(filepath="./objects8.blend")

-- import the model

import bpy
bpy.ops.wm.open_mainfile(filepath="./objects8.blend")

Works great for me. I have some issues recreating stuff you can do in the GUI, but its mostly because Blender has terrible documentation for code (imo). Still, you can do sweet stuff since you call all the equivalent commands directly in python and it executes using the bpy module.


Checking if boolean true or false not working

You store the current state in an intermediate variable. This can't work. You need to store it in a storage that will survive at least till the next call access. I wondered that you did not get any errors.

There are many ways to solve that issue.

FSM (build in state machine)

One way is to use the build-in state machine.

You can define a "jumping" state that, (when current) tells the character is currently jumping. On the other hand, if it is not current the character is not jumping. You do not even need Python to do that.

any state can transit to jumping state:

The jumping state cares the jump e.g. playing animations, detecting collisions and switch to other states

Property

You can create your own state machine. E.g. by using a property of the game object:

jumping = cont.owner.get("jumping")

# this triggers when I press space.
if not jumping and isJump.positive:
       cont.activate(j) # what is a "j"?
       cont.owner["jumping"] = True
       print("Jumped")
       cont.deactivate(j) # this will not take effect

# Better separate start jumping from jumping.
# This code does not need to be executed when there is no jumping, regardless of the collision sensor result.

if jumping and collide.positive: #<-- This whole block works fine
   cont.owner["jumping"] = False
   num = 0
   print(num)
   cont.deactivate(j)

There are much more ways. I hope it helps a bit.


Parenting to the character's vertex was what I was looking for. To do so:

1) Select everything.
2) Enter Edit mode (tab), and select the vertex you want to pin to.
3) Exit edit mode.
4) Select the object(s) you want to pin.
5) Shift-select the character.
6) Enter edit mode. The vertex should still be selected.
7) Press Ctrl-P to parent to vertex.

The objects will now follow around that vertex as it deforms.


Why do I have a large black and white artifact on the rendered image?

That big error on the top is caused mostly by Fireflies and how the denoiser works.

The denoiser has a hard time dealing with small bright elements surrounded by darker pixels, as is the case with fireflies, and creates new artifacts instead.

Just for comparison here's the image with the same number of samples and no denoising (those random bright pixels are the fireflies):

For other examples see:
How to properly denoise renderings?

What is the solution?

You need more samples and less aggressive settings for the denoiser

Or get you can get rid of the denoiser completely and use some clamp indirect to control the fireflies.

But you can also avoid those hot spots and fireflies if you change the lighting on the scene.

Don't use point lights, or very small lamps, to light shiny and transparent objects...

They will be reflected as bright shiny points on the surface and are more likely to cause fireflies.

If you use large area lights fireflies are less of a problem. Here's the same scene at 600 samples, no denoising and no clamp indirect.

For tips on how to light shiny objects read:

https://blender.stackexchange.com/a/50576/1853

Other advise. Try to avoid high levels of subdivision (like you have in the plane used as the background). You are generating a very large number of unnecessary vertices by setting the subdivision to 6. Very rarely you would need more than 3.

Read: Blender render crash when using subsurf modifiers.

Last piece of advise: Try to make your objects to the size they would be in the real world. Your bottles are larger than a house at 9m tall. It makes a difference in terms of the size and intensity of the lights (and if you are going to do any kind of physics or fluid simulation), and also in terms of the depth of field on the camera.


How to remove text written over top of FloatVectorProperty

Set the text of the layout
If text argument is not set in layout functions, it defaults to the name of the property. Set it to "" to "remove".
    col.prop(settings, "normal", text="")

Note: will also take out the prop name written above. Can be replaced with
    col.label(text="Normal")


You have turned your viewport shading to "Rendered".

In order to edit your mesh, you need to switch to either

Material
Textured
Solid
Wireframe

Solid should be the default mode and is the most common mode for editing.

You can use shortcuts to switch between modes:

Z --- Wireframe

Shift+Z --- Render View

Alt+Z --- Texture View


CUDA error: out of mem aloc result line 855. Does anyone experience the same issue?

Try rendering using CPU.. because I guess the 8GBs of GPU memory can't handle 13GBs of your scene memory. I've faced with with 4GBs of card and now I only use GPU for testing the scene in realtime live preview and always render with CPU.

when using GPU, Blender push the whole scene to GPU's memory and then CUDAs start rendering the image. while using CPU, the core starts rendering using CPU's core and threads.

Edited

Secondly you should try to lower down the memory load on GPU... 8GB is good memory for an average scene. There are many ways to reduce the momory in scene i.e.

if you are using HDRI.. user a step lower in size i.e (if you are using HDRI of 8K, try to use 4k or 2k and see what effects.
If you are using large textures, try to lower down their resolutions too.

You can also try with out all of the textures and see if it renders so quick then start enabling a few and then a few and then a few and each time render the scene with GPU.

And Last but not lease... try rendering the scene in lower resolution like.. instead of 4k of resolution try rendering in 50% or 25% in scale percentage.

If you are still unable to render this.. then as blender says..

https://docs.blender.org/manual/en/latest/render/cycles/gpu_rendering.html


My goal is also to make .MD2 models for my mobile app, so here is my way:

The SceneJS page that MCunha has suggested is a good start.
It says that we need to install the MD2 exporter plugin into Blender. Unfortunately that link for the necessary md2_export_263.py  file is broken, but here is an actual one from jerrylroberts' GitHub repository.
Download it.
I've followed the SceneJS page's instructions on modifying the source code (I don't really know if it's needed or not).
In Blender 2.78c go to File > User Preferences... > Add-ons > Install from File..., browse for the above mentioned (and modified) Python file, then activate it by clicking on its checkbox.
Select the mesh you want to export. It's important for it to be unwrapped and have at least one associated UV-Texture material (according to MCunha's first UFO:IA source). Then go to File > Export > MD2 (.md2)

That's all. I've checked the exported model by G3DViewer in Ubuntu and it seems to be okay.


Nurb path not rotating or moving in lower section of double pendulum

I managed to build the double pendulum.  The simulation shows the expected chaotic motion of the two pendulum bobs and so it looks like the Blender physics rigid body simulation is accurate.


normal map shows up slightly offset on mesh, but only in cycles render view

I finally figured out what was going on.  I discovered that since I had a mix shader that was mixing 2 normals together, and one of the image textures for the normals was conneted to a mapping node, so because of the mix shader, the mapping effected the other normalmap as well.


Yes, you can use higher subsurf levels by typing the values directly, rather than using the slider.
See How can I set sliders to values outside the limits allowed by their slider?

However in this case it looks like the bumpiness is more likely to have been caused by something like this:
Weird deformation between large ngon and edge ring
To fix it, try adding some supporting geometry.


You have extra faces here:

In edit mode use Mesh>Vertices "Remove Doubles" (or choose "remove doubles" from the toolbox>Remove:>Remove Doubles.


You can do this with a VideoTexture script, use the script at the bottom of this thread

http://blenderartists.org/forum/showthread.php?189973-Changing-object-textures-in-game-engine-quot-on-the-fly-quot-(animated-textures)


Wacom Intuos Draw CTL490DW Digital Drawing and Graphics Tablet compatible with Blender?

Considering Wacom Tablets are basically mouse/pointing devices, there is literally no reason it wouldn't work. I have a Wacom Tablet myself, and it works excellently for painting, although for 3D modelling, a 3D mouse would probably be more useful.


I believe thts a problem with the UV Map itself u probally need to remap and divide the seams cutting the truck in half first.


Why will Blender sometimes not select the object under the cursor

Because there is margin distance (in screen pixels) such that blender will select an object even if you click slightly next to it.

So that mesh gets selected instead of armature because it is on top of the armature and the pointer is within the margin area. When you zoom in the pointer is no longer in margin area and the armature is now the top most object.

Honestly blender could do picking much more smartly and also check if something is directly beneath pointer even if closer_to_camera mesh qualifies for selection.


This is a simple addon that using the scaling principle allowed by the NLA editor.

Its features:

Auto-baking
Works on rigid bodies
Auto-alligns so it starts and ends exactly where the previous animation did

Installation:

Go to https://github.com/FreddieRa/BlenderAddons/blob/master/AutoReverse.py
Click on "Raw" on the top left
Then right click anywhere and click "Save page as"
Save it as "AutoReverse.py"
Go into Blender and go to "Addons" in user preferences and click "Install from file"
Navigate to where you saved the .py, and then tick the box when it appears in Blender

How to use it:

Simply press "space" and type "Auto Reverse"

There are two different things this can be used on, normal animations, and rigid-body simulations.

For animations:
You don't need to do anything except have at least two keyframes

For Rigid-body simulations: All you have to do is place a keyframe (of any type) at the start and end of the section you would like reversed. This is just so you can select part of the simulation, or all of it like in the picture. Keep in mind it will be baked and so the rigid-body nature will be removed, however this can be put back in afterwards.

Tips and Tricks;

Use "Cell Fracture" to split a cube, a forcefield modifier to blow it apart and then "Auto Reverse" to change it into an animation of all the pieces flying back together
It will reverse everything selected so you can use it on multiple objects at once

How it works:

This works on the principle of scaling a block of keyframes, but in this case by -1, in order to invert them. It is done around a central point so it's not shifted at all, and baked in order to produce a better result.

It automatically gets the first and last keyframe of any animation and then simply reverses it. It also works on objects that are already baked, meaning that you can repeat it on the same object, and just flip the animation backwards and forwards if you wish to.

So there you go, use it, mess around with it, it's all commented so you should be able to see what's going on. I welcome comments and suggested improvements.

This is my first addon and so I will have made mistakes but I just hope this saves people time and can be used for interesting projects!

-Freddie


The reason you are having problems is because you added a Mesh Circle instead of a Curve, Circle. Look more closely at the video 20:05, where he Add > Curve > Circle
Thats not the same as a Add > Mesh > Circle !
See screenshot below :

In the Outliner it should say BezierCircle  :)


How can I create a bump line across an object using textures?

You can do the following...

Add a Bump Node
Add invert node to your bump map texture.
Plug it into the height input on the Bump node.
Plug the bump node into the Normals channel of your shaders.
Adjust the strength value on the Bump node, to match your need.

Note bump is exaggerated for demostration purposes.

Here is the blend file.


Draping 2D image over point cloud or mesh

To drape an image over a 3d mesh is easy.
First bring you image into blender, I'd use the import image as plane add on. Next, as gandalf3 said, use a shrink wrap modifier to drop it over the mesh. by doing that you can avoid any distortion that would occur when using the cloth simulator.


Beveling on extreme concave/convex Edges

If using Bevel you have 2 general options:

bevel the geometry as it is but just at small amount.

This will add tiny beveled edges on your existing geometry; while using Ctrl+B add just a bit of effect. To ensure that no clamping would happen use Bevel modifier with Clamp Overlap option enabled (or while beveling in Edit mode with Ctrl+B press C to enable the same option).

May be not the best solution because if there are tiny long quads (which are not good thing in general), they will make clamping occur really fast and thus beveled effect would be barely visible (across all the mesh).
dissolve / delete some of the edge loops where they are near to each other.

This means that you get rid of some edge loops of your model (like those in the bottom part of your mesh) for beveling to work as expected. Once it was done you can add those loops back if you really need them or add Subsurf modifier to subdivide that geometry (depending on the case).

One more option is to smoothen edges of the mesh with Subdivision Surface modifier. Basically it's one of the mentioned techniques in the Keep sharp edges when using Subsurf - supporting loopcuts. Add them in the corners and add modifier. Note that this increases amount of geometry quite much so keep that in mind.


Motion tracking, scene doesn't line up with tracked data.

About the tracking points level ... maybe you have not set up the camera settings properly. Matching the cam settings (lens, sensor etc.) to the real camera, the footage was taken with, once did the thing for me - which you always have to do to get a proper result.

Hope that helps.


Scale Faces by Specific Value in XY Axis?

You can use the operator panel to do that:

Once you have validated the scale, you can set the values manually.


Actually the bump node is working, but the effect is not noticeable due to 2 reasons:

1) your texture gives only 3 values: one value for black, one for blue and one for darker blue, with no transition between one value and another, while the bump illusion is created through some gradients (it's the same reason why a beveled object has more appealing edges than its sharp version).

2) you don't have any reflection shader, which adds some details to the illusion of depth.


How can I script moving bone constraints up the constraints stack?

This can now be done without bpy.ops.

bone.constraints.move(from_index, to_index)

https://docs.blender.org/api/current/bpy.types.ObjectConstraints.html?highlight=constraints%20move#bpy.types.ObjectConstraints.move


Is there as way to export a blender object for cnc machining so it doesn't become a huge file size when converted to .stp?

This is a good question, and the answer unfortunately is mostly "no". IGES and STEP files are (mostly) CAD/CAM files, and are not point- or polygonal-based. The file format itself is ASCII, and dates back into the 70s. It is great for driving CNC machines, since that's its history.

Some modeling programs (Rhino) can get you there from nurbs-based modeling. I am not aware of any option in Blender (or ZBrush, Maya) allowing you to get a clean IGES.  You can get STL files, which are great for 3D printing and which some routers will accept.

There are a number of programs that will go back and forth between Nurbs, STEP and IGES...  and some higher-end products (SolidWorks) will bring in an stl and generate an IGES or STEP.

If you finda  better answer -- post here. We use Blender for a lot of 3D output, but when we need tooling, typically we need to have IGES... and this is the best info I have at the moment!


How can I render Volume Scattering on all my layers?

You should use the render layers mask feature.  First divide up your solid objects between render layers however you would like.  Then, place your volume object on its own separate layer.

With the volume layer active, select the squares that correspond to the solid object layers using the "Mask Layer" selector.

Here is a sample result I put together.  Each cube is in its own render layer.

And this is what the volume layer looks like by itself.  You should combine the layers using the alpha over node.


How do you make Blender Game the full screen?

Yes, there is an option in the properties menu.


How can I change blender´s 2.78 splash screen?

I have meanwhile solved this one. The key is to rerun Cmake once you have modified the splash.png and splash_2x.png files. Cmake is where the conversion of the files happens. And that's why nothing happens when you just modify the files.

So modify the png files, clear cache in Cmake, configure in Cmake, generate in Cmake, then compile again.


Cast light from one Object onto another Object

In Cycles:

Set the desired Emission node value to your Sun-sphere;
Put, a bit in front of the Sun-sphere, the spot lamp lighting the Earth-sphere. The lamp's strength should match the emit value. And align the lamp with both spheres.

Done


How to make a single user copy of a group of nodes in matrial on python in Blender?

The copy function can be used on the node tree as well. The copy function returns the copied node group, so it can be used replace the original group with the single user copy:
original_group = bpy.context.objects['Object'].material_slots['Material'].material.node_tree.nodes['Baking_node'].node_tree
single_user_group = original_group.copy()
original_group = single_user_group

Then just loop that over all your materials


How to cut a mesh by specifying the angle

It isn't currently supported yet, but still possible. You can say that the angle constrain is based on View coordiante, so let's try a tricky way:

Install Precise Align addon (not a must-have, but very effective here);
Select three vertices, including the specified vertex, click Create Empty button in Precise Align panel in the Tool Shelf (T). Click on Swap Empty Origin button to set it at the specified vertex if it hasn't been there. Also make sure Parent to Object is toggled;
Select the empty, ShiftNumpad 7 to Align its local Top view (Local Z axis towards viewer), thus you can make one adjacent edge visually horizontal (or vertical);
Keep the current point of view, R to rotate the empty along its own pivot point by a specified angle (or the complement/supplementary angle, depending on how you rotate it);
Select the mesh object, enter Edit mode, enable Knife tool, press C to constrain horizontally or vertically based on the view (screen) coordinate. Repeat it if needed.
Delete the empty. The mesh rotation will be regressed automatically.

A demo video for better understanding. It's not perfect, but works.


You are thinking of this backwards from how the ray sensor works. You want to look for "target" no mater what is in front of it.

Add a property to everything you want to get hit say "target". Then change the ray senor to look only for that property ("target") and enable X-Ray Mode.

Last your code can then look like this.

if ray.hitObject:
    target.worldPosition = ray.hitPosition

X-Ray Mode will let the ray look through everything, and the property will only return the objects with the property "target."


Is it possible to round the edtes of a round corner

Add a subdivision-surface modifier, and then add loopcuts around the top and bottom. Move these loopcuts near the top and bottom of the mesh to help shape the Sub-surface modifier.


The objects in the file you provided in the comments of your question are linked copies.

Select them all together;
press F3 (or spacebar, if in blender 2,79 or earlier);
type "make single user" to find the "Make Single User" command and click it;
in the popup that appears check "Object Data" (see img) and press OK.


Left Click doesn't work at all on Mac, even after reinstallation

Alright after a long battle I managed to delete every single file related to blender on the computer and reinstalled and now it works. Considered the question solved.


Material not rendering properly in blender cycles

Material is rendered properly.Its your nodes that need to be configured properly in order to match the one in tutorial, and your lighting setup doesn't seem to match the one in tutorial, along with perspective.


Custom hotkeys in pie menu (with out numpad)

There is no such functionality in Blender currently. You can just keep the hotkey that called the menu down and drag the mouse in the direction of the option you want to chose and then release the hotkey. Or you could set the Confirm Threshold to something that is convenient to you in the preferences:


In edit mode with all the faces selected, press space type split and select Edge Split. Then press P > By Loose Parts. Every face is now a separate object.

Warning separating 3000 faces into different objects will take a while, if not crash blender.
After splitting the faces, you may have to brake up your mesh in to smaller pieces, then run the By Loose Parts command. You can select (say half of the faces) and separate them into different objects with P > Selection.

If you need the new objects' origins relocated, you can select all the objects and press ShiftCtrlAltShiftC > Origin to Geometry. Or if that keyboard short cut is too long, in the 3D view header Object > Transform > Origin to Geometry.


How to smoothly rotate an object from one direction to other

You can use an auxiliary vector n which indicate the direction of the cone, and make n to be a mix between the direction to the target and another vector n0. Then the coefficients of the mix should vary smoothly in time.

import bpy
import mathutils

context = bpy.context
scene = context.scene

obA = scene.objects.get("Cone")
obA["speed"] = 0.1

df = 30
n0 = mathutils.Vector((1., 0., 0.))

def setloc(scene):

  a = bpy.data.scenes["Scene"].frame_current
  if a < 60:
    loc = mathutils.Vector((8.0, -0.05, 0.0))
    dv = loc - obA.location
    n = dv.normalized()
    rot_quat = n.to_track_quat('Z', 'Y')
  elif a < 60 + df :
    loc = mathutils.Vector((-10.0, 14.05, 7.0))
    dv = loc - obA.location
    n = (df-abs(2*(a-60)-df))*n0 + (2*(a-60)-df)*dv.normalized()
    rot_quat = n.to_track_quat('Z', 'Y')
  else :
    loc = mathutils.Vector((-10.0, 14.05, 7.0))
    dv = loc - obA.location
    n = dv.normalized()
    rot_quat = n.to_track_quat('Z', 'Y')

  obA.rotation_euler = rot_quat.to_euler()

#rotation
  speed = obA["speed"]

  if speed > 0.000001 and n.length > 0.000001:
    obA.location += speed * n.normalized()

bpy.app.handlers.frame_change_post.clear()
bpy.app.handlers.frame_change_post.append(setloc)


Blender cycles won't render halo particles

To render Halos in Cycles you need two objects: an emitter object with a particle system, and a second object that acts as a domain. The domain object should enclose the emitter object plus the area where the particles will be.

On the domain object you can use the Texture->Point Density node to control an emission shader that will be used as volume for the domain:

Select as Object the emitter object and its particle system, plug the density to the strength of the emission shader and lastly plug the emission as the volume for the domain's material.

Example file:

NOTE: Currently (version 2.76) this method works only on CPU rendering, no GPU yet...


How do I make my textured plane into a cylinder?

Why so? Instead,  make a NURBS/bezier semicircle and extrude it, setting the desired value in the Geometry section. Convert it to mesh, solidify outside and texturize the wall inside.To do that give it a different material color.

or simpler yet

Add a circle mesh, remove half of its vertices and extrude. Then do as above.


The installed fonts which are not shown in C:/windows/fonts are located at
C:/Users/USer Name/AppData/Local/Microsoft/Windows/Fonts
You can browse through and select the fonts..


Hot to upload a new font (OFT) file into blender

Create a text object and in the font section of the text panel you will see four choices for font.  Click the buttons and navigate to your directory.

The tool tip shows where to click.

I have made the text panel in full zoom.  You can see text choice at the text properties selected at the top.


Object origin/pivot point perpendicular to an object

Your question is a bit wrong and unclear, imho, for a few reason, I try to explain why:

You wrote "Object origin/pivot point" as to be "not perpendicular" but a point has no dimensions, and thus it can't be "perpendicular" or not to anything.

What you mean is "the three axis" that come out of the pivot/origin point. And this makes a big difference, because there are different "sets" of those axis, depending on the coordinate systems you refer them to. And they are specific of that 3d view area.

Those are known as "transform orientations", because they help you, pointing in the possible transform operations you can perform on the object.

By default you see the "global" orientation, but you can choose from a set of predefined orientations.

Here you see the same object, at the same time, shown in two different 3d view areas, with two different "transform orientations": note the effect on the pivot/origin axis

adding to this, in the properties panel (right side pressing N) at the bottom there's a dedicated panel, where you can also switch them, but here you can create a "custom" orentation, at your taste, too! Look at the small "+" button in the lower right corner:

In object mode those axis are always "cast" from the object's pivot/origin point but, in edit mode, that pivot is where the "selected" (average) part of the mesh/curve/other is:

Adding another example the "view" orientation makes those axis always "perpendicular" to your view:

in edit mode, you can spot the difference that the "normal" orientation can make:

here you see both orientation at the same time, again, but in edit mode

When you tranform the object, in object mode, or its mesh, in edit mode, you can be helped by those axis, because both the 3d manipulator (grab, rotate and scale) and the "visual guide" you get when you put transform constraints (pressing the axis letter).

see how all of the manipulator modes adapt to the selected transform orientation:

And, if you choose to grab a face - in edit mode - along X along "normal" transform coordinates

if you have this ("local" transform orientation mode) in edit mode:

when you press G, the transform start without contraints (you can grab it anywhere)
if you then press X a "visual guide" appears, locking the movement along "global" X, always, independently from your "transform orientation" choice in that 3d view area

if you press X again, the visual guide, and locking, is now bound to your choice...

eg: if you choose "local", pressing XX will guide and lock your transform along "local" X

The blender manual has a whole chapter dedicated to this argument, explaining every single bit: https://docs.blender.org/manual/en/dev/editors/3dview/object/editing/transform/control/orientations.html

Now, learn how to "correct" them, imho you should keep in mind (and specify) which orientation you wish to manipulate. A comment above points you to another similar question, with a solution. Try that and, if it doesn't work, improve this answer adding more details or open a new one, if it is a too different case. Hth


Can a "Blender Game Engine" powered game run on Linux?

Yes. Blender Game Engine powered games can run on all major platforms, and support for Android deployment, although limited and regarded as experimental by the community at large, is gaining ground. Deployment to Linux based systems is fully supported, and is a primary focus of the Blender Game Engine.

Keep in mind that a game created with the Blender Game Engine must be built for the system in question by someone with rightful access to the source files. This means that a developer must build their game for Linux in order for the game to run in a Linux environment. The same holds true for the other available platforms. A game built for Windows will only run in a Windows environment.

One exception is Android, where (correct me if I am wrong) support only exists through a native application which requires the source file in .blend format. Again, this functionality is regarded as experimental and as such should not be considered a viable deployment solution at this time. The Blender Foundation provides limited insight on this subject, however relevant information can be found in the Official Documentation here and here.

From the Official Documentation for the Blender Game Engine:

  The Game Engine can simulate content within Blender,   however it also
  includes the ability to export a binary   run-time to Windows, Linux
  and MacOS. There is also basic   support for mobile platforms with the
  Android Blender   Player GSOC 2012 project.


How to instantly stop the rotation of an object in BGE?

This appears to be a reported bug

Workaround: use a very small value like 0.00000012

def rotation():
    if (mX < 0.10) and (mY < 0.90):
        cam.setAngularVelocity([0, 0, 0.1], 0)
    elif (mX > 0.90) and (mY < 0.90):
        cam.setAngularVelocity([0, 0, -0.1], 0)
    else:
        cam.setAngularVelocity([0, 0, 0.00000012], 0)


Adding Particle System through blender script

It seems modifier_apply() only works for those modifiers that have an Apply button, but when you add a Particle System as a modifier the only button on the modifier is Convert, which calls bpy.ops.object.duplicates_make_real() , that's probably what you want instead of Apply.

Something like this:

import bpy

obj = bpy.context.active_object

if len(obj.particle_systems) == 0:
    obj.modifiers.new("part", type='PARTICLE_SYSTEM')
    part = obj.particle_systems[0]

    settings = part.settings
    settings.emit_from = 'VERT'
    settings.physics_type = 'NO'
    settings.particle_size = 0.1
    settings.render_type = 'OBJECT'
    settings.dupli_object = bpy.data.objects['Cube']
    settings.show_unborn = True
    settings.use_dead = True

    bpy.ops.object.duplicates_make_real()


Understanding Rotation in Blender (scales on sphere)

If you wanted to rotate an object around its z local axis in blender, what do you do? Do you change the rotation z euler value? Or do you use the rotate operator in the local transform orientation? Changing the rotation euler's values rotates the object in its global space, not in its local.

So, how do we rotate in local space in Animation Nodes? The answer is matrix multiplication which is the underlying mathematics behind blender's rotation operators. Compose a translation matrix that include the object's locations, then multiply that by the Rotation Matrix Output of the Direction To Rotation Node, then multiply the result by a rotation matrix, the last matrix act as the local transformation, so by editing its values, you are locally transforming.

Another method would be to use Hamilton product on Quaternions, they are a little harder to understand though. Simply multiply your quaternions by another that include your local rotation information.

Yet another method would be to edit the guide axis to account for your rotation. See the documentation.


Invisible wall? Are you sure it isn't just the fluid domain?

Check your other layers. It's possible one of them has an object in it that is interacting across multiple layers and influencing your fluid sim even though it's not on the same layer.

Also try pressing alt h to unhide all objects. Try setting the obstacle to volume only. Test these out by baking at a low res so you know it would work with a higher res.


I've solved the problem, you have to smart uv project the mesh before exporting.


I now understand that you can create a value socket in the Group Input node. This can be done in two different ways:

1) create a Value node and connect it to a Group input socket. Then you can reconnect that Group Input socket (with color grey) to a Color socket in your node group

2) you can duplicate an existing Group Input socket (value socket), rename it and connect this value socket to a color socket in your node group


Is there a way to limit the particle system?

Use weight paint to limit grass particles near the wall of your building.

Weight Paint mode.  Hair is yellow. Red to Blue gradient. Red areas specify the most hair. Blue areas specify no hair. Gradient between Red and Blue specify values between the two extremes. The Yellow arrow in the Vertex Groups Panel of the Particle Tab shows the vertex groups selected for Density and Length.

Meshes with hair/emission particles can use  weights produced by  [weight paint] mode. Then  hair will be produced in certain areas.  This produces vertex groups. The particle system [density under vertex groups] can respect the vertex group. Some areas can have hair or grass.  Other areas can be excluded from grass.

Your model must have enough vertex density for fine detail.  Please click on image above to see higher resolution closeup of the image. The vertex vertex denisty will be more readable.

For example.  Eyelash areas on a face can be weight painted.

So you could weight paint your mesh and exclude areas too near the building wall.  If you have only a still photo image and not a moving image you can be less precise.

Perhaps related

How do I make a section of hair a different color?

This is not a tutorial on weight painting .. yet other questions here at BSE and the video web site that  has a name that rhymes with newnube cab be searched.


I tried to create and download a model from the link you posted in your question, and my OBJ is correctly imported (I used one of the sample pictures on the link). The object's vertices location is not convenient (as shown in your picture), but the pivot is on the world center, so to quickly translate the mesh to the center and keep the pivot:

go to Edit Mode, and select all vertices
press Shift+S and choose Selection to Cursor (Offset)
then in Object Mode rotate and/or scale the object to position it as you prefer.

Anyway, the procedure to import the OBJ in MeshLab and export it to PLY format is a common practice, because PLY format keeps the Vertex Color data, while OBJ can't (so what you did is a good practice). So my suggestion is to use PLY format instead of DAE.

P.S.: When you see an object in the outliner, but not in the 3D Viewport, press the "." key on the numpad to quickly focus on the object without scrolling your mouse wheel.


How do I give a completely black object a glow effect?

It looks like you want Eevee for easy bloom?
You can repurpose an edge lining technique for it.  Give your object two materials and a solidify modifier with a material offset.  Make one material black, and for the other, give it emission for backfaces, but transparency for front faces:

Note that you'll need to enable some sort of blending (alpha clip is fine) and make sure you're not culling bakfaces, in material settings as shown.
There are a number of additional ways you could achieve this, constraint-placed shadowing meshes, render layers, and probably others.  But this is previewable, simple enough, and should get you what you're after.


Why cant I animate using shape keys or locroc

You can use shape keys, they seemed to be empty though (I'd use shape keys to make the tentacles ribbon/wave-like motion for the edges).
For the tentacle motion I'd use bendy bones -


Access body of Message actuactor through logic bricks

No, there is no way.

The reason is simple: what should happen when there are two or more messages?

There are way too much options to process a body (and several bodies). The information you could get is if an message with a certain content was received. The filter by subject already does that.

I agree the API looks inconsistent, as you can set a body without any use (without using Python). I see it as simplification, when you have a lot of simple message senders, but just a few  (more complex) listeners. I usually use the body when I have more information than the pure existence of a message (subject) can express.


You can use a camera view. The perspective "camera" is not accessible.

Create a camera.
Set both views to that camera.
In the editing viewport press N to open the properties panel, then check Lock Camera to View.

When you manipulate the view in the viewport, you will not exit the camera, but change its transformation.


Brand new to Blender. Should I download 2.79 or 2.8 beta?

Blender 2.80 is a beta version, under heavy development (there are still 1121 bugs as I'm writing: https://developer.blender.org/maniphest/project/2/type/Bug/). It is a major version, with a lot of changes in the workflow.

Therefore, as of now, 2.79 is more suitable for projects as it has more documentation and is way more stable.

If you are simply willing to explorer Blender, to learn it, and are ready to accept random crashes or occasional unexpected behaviour, you can go for 2.80.

If you are also new to CG, you should go for 2.79 but have a play with 2.80 to get ready for a future transition.


UV mapping is used to position a vertex on an image. The U and V values for a vertex are between 0.0 and 1.0, a value of 0.0 means it is on the left or top edge of the image, while 1.0 means it is on the right or bottom.

Whether you use a 512x512 image or a 4096x4096 image, a value of 0.5 will always be in the middle of the image. Where a face uses vertices that are 0.25 apart, the face will use one quarter of the image, a larger image means more detail on the given face.

In your example, you layout the UVs on a 512x512 image and then use a 4096x2048 image. As the new image is twice as wide as it is high the texture gets stretched in the one direction, which depends on the face orientation on the image.

If you want to increase the texture detail, you want to increase the image resolution the same amount in both directions.

It is possible to bake multiple textures onto one, which sounds like what you want to look into. To get the result, you want to make a new UVLayout that positions the multiple materials onto different parts of the image and then you bake the old materials onto the new image. This method allows you to convert between a square and rectangular image texture.


Sheep it is free to use. Your projects will be prioritized if you have enough "credits", which you obtain by sharing your CPU/GPU (that is, rendering other users projects), but that's not mandatory.
Sheep it Renderfarm


You've just gotta switch to face select by  clicking on it or pressing the number 3, but not numpad 3.


Why doesn't constraining to a vertex group behave like parenting to vertices?

When using a "Child Of" constraint with the vertex group option, because there can be any number of vertices, the rotation must be derived from a mix of all the vertex normals.

Even if you just use 3 vertices in the vertex group, the normals of those three vertices will be affected by other vertices that are not part of the vertex group. If those three vertices are connected by edges to other vertices, the connected vertices will affect their normals.

When doing a vertex parent, there is a guarantee of only three vertices so the algorithm is a simple barycentric algorithm.

If you make a duplicate of the three vertices in your group and detach them from other vertices you should get the same behavior with a "Child Of" constraint that you would get with parenting to three vertices.

One possible workaround would be to duplicate the vertices you want to use with the constraint so they are not connected to any neighboring verts that could affect their normals. You could delete their faces so they don't show up in render. I tried the mask modifier but it kills the constraint.


In Blender 2.82a what is the shortcut to get out of loop cut state?

To get out of loop cut mode, one can simply click on the select box in the left toolbar.


What happens if you copy blenderplayer.app over to that empty folder. Then, you could use it. There is also likely a preferences input for the player path. I once copied blenderplayer.app from one computer to another through Google drive, I think it worked (it was a while ago). I am currently not with my computer, but good luck!


Is it possible to de-bevel all or parts of a mesh?

If I didn't use a bevel modifier but I beveled directly the shape edge of the mesh with Ctrl+b, I usually use this procedure:

In edit mode, set the Pivot to Active element;
select all edges I have to de-bevel and for last one I select the one aligned to the original position that I will use as reference;
scale the selection to 0 on the needed axis only, to align all beveled edges to the reference edge;
repeat the same operation with the other side to de-bevel changing the last selected edge and axis accordingly, as needed;
Remove double vertexes.

This works on one "beveled corner" at once and if the edges to be de-beveled are aligned or orthogonal to axis. If they aren't there is the need to set a different xyz ref system to match local edges alignment.

If you wish, see the following video to see the tutorial I made:

http://sendvid.com/5rs3n0uz


@ItsRay, it looks like you copied then inverse-pasted, but as long as you don't press i to insert keyframes, no keyframe, and therefore no pose, will be saved, unless you've activated the Automatic Keyframe Insertion button in the Timeline header bar, which would allow to automatically create the new keyframes, but I don't think you've activated it.


Boolean difference not carving correctly

you could try the following:
Go into edit mode, press a to select all, then w and remove doubles
now back into edit mode, press ctrl+a and apply the rotation and scale.
now try the boolean modifier again

are there any other things in your modifier stack ?


Noob Question: Unable to Weight Paint my Mesh

You can select the corresponding vertex groups in the mesh properties, or go to object mode, select the rig, shift select the mesh, enter weight paint mode and select the bone with Ctrl left click.


How to combine three non-orthogonal cylinders with sphere

It might be an idea to use the skin modifier in combination with particles? It's pretty easy to set up and manipulate.

Create a mesh and then in Edit Mode delete 'Only Faces' - essentially leaving
you with a wire-frame.
Add the skin modifier and then a sub-surf modifier to smooth.
Create a Sphere object.
Add a particle system set to hair and choose Verts from Advanced
settings.
Under Display choose the Sphere object.

The particle system will have to be moved up to the top of the modifier stack.


How can I animate a mesh moving in a spiral fashion?

Plane with Curve Modifier animated with Curve Location

The Curve is animated on the X axis with 2 location keyframes.

Spiral, Plane, Lattice in the image above.

The paper in edit mode, high density, loop cuts in both directions to suit your needs.  The Curve Modifier on the paper performs the rolling.

2 options at least.

The spiral moved on the x axis toward the paper.

The paper moved on the x axis toward the spiral.

The spiral is the parent of the lattice which slightly squeezes the middle.  The lattice is optional and influence can be animated.  The spiral was created with the standard addon AddCurve extra objects.  The tail was extended on the x-axis to control the tangent and flatness in the XY plane. The origin was moved to the last point of curve.

In the picture above you see the origins of the spiral and the paper.  Be very aware of those locations.

More middle squeeze with Lattice.  The origin of the lattice is in the center of Spiral.

GIF created with GIMP.  Please excuse the jump.


how does the color ramp interpolation work?

An easy way to visualize this is to add a plane with a displacement modifier with a Blend texture and Colors > Ramp selected. Start by adding and subdividing a plane:

You can add a subdivision-surface modifier as well for added detail. Now add a Displace modifier, and click New to make a new texture. Go to the texture panel and select Blend:

Now you can edit the waypoints and the interpolation types as you wish and view their results in real time. This will really help you see how the colors are mixed using a color-ramp.

Constant:

B-Spline:

Linear:

Cardinal:

Ease:

To visualize Cycles

Add a plane, unwrap it and add a gradient texture to an emission shader:

LINEAR

QUADRATIC

Easing

Diagonal

Spherical

Quadratic Sphere

Radial


Ctrl + Tab is your friend here. Got into edit mode and switch to Vertex selection. Select the vertices you want to delete, hit x, and select "Delete Vertex." Delete has several options, and some of them are selective. My guess is that you have been selected "Delete only faces" or something like that.

Another trick: select 1 vertex of the item you want to remove and hit the L key, which will selected all linked geometry. Usually it'll select the whole object you're wanting to delete.

Also make sure that you've applied or removed any modifiers when you have mesh geometry issues like this—will save you a headache later on.


With the cloth simulation, you want to select your dollar bill object and go to physics tab; it's in the Properties window under the Outliner by default, same window you go to for your particle systems. The icon is a bouncing ball. If you can't see it, over over the panel and scroll until it's in sight, or enlarge the window. Hit the cloth button. You're going to want to play around with the stiffness setting in particular. You don't want it to act like a dollar-printed hankie. Once you have setting to work with, you'll need to let it run it's simulation. You'll probably do this several times until you get something you like. After you're finally satisfied, bake all your dynamics.

Go back to your particle system; make sure you have gravity on. Mess with the weight values; your money could just be too light. Finally, apply the bill's orientation so that the origin is in the middle of the bill, and it lays flat on the floor by default. That part should help with the standing problem, at least.


How do I make text that looks like it is made out of a ribbon?

The base is to use a Bezier curve with a bevel object (which needs to be a curve too).

For the overall shape curve, add it by : ShiftA then choose 'curve' and 'Bezier'.

For the ribbon curve, add it the same way and flatten it : enter edit mode Tab, then scale it 0 along Y (as its shape is by default curved on Y) SY0.

Come back to object mode Tab.

At this step, you have two curves like this :

Now select the first one (overall shape curve) and assign it the second curve as bevel object (in the geometry part of the curve tab, as shown below) :

You can see that the ribbon curve is propagated along the overall shape curve.

But the ribbon is a bit large, so scale it down a bit : select the ribbon curve and scale it down S and move the mouse :

Now all is about extruding the overall shape curve.
Select it, enter edit mode, select an extremity vertex (control point) and type E and move the mouse.

Alternatively, you can also extrude with LMB holding the Ctrl key simultaneously.

Eventually, you may need to subdivide some parts. Same can be done selecting two control points and with W then subdivide :

With these basic operations, you can 'draw' your shape.

Last operations to know :

You will need to twist your curve CtrlT then move the mouse:

And you will need to adjust the ribbon size AltS then move the mouse:


Blender 2.9 viewport overlays - show everything but verts, edges and faces in edit mode

Workspaces can achieve that behaviourn, as I don't think there is a built-in way for "remembering" overlay settings.
You can add a workspace using the + icon on the right of the top ribbon, and customize it as you wish, it won't affect the other ones.
Then when you want to go back to the previous state, select the original 3D Workspace.
Note that you can append workspaces from other files if you want to retrieve a particular setup from another project.
You can also change the layout in a new file and save it as the new default if you wish. Go to File > Defaults > Save Startup File.


In the UV editor press N to display the Information panel on the right.  At the top is the UV Vertex section where you can type the values directly.

Based on what you've said, it might also be useful to enable "Snap to Pixels" in the UVs menu.


Lattice Modifier not listing available objects

You have to add a lattice object to the scene (Shift+A> Lattice). Then, after selecting the object you want to add the lattice to then the lattice (the order matters), you can do Ctrl+P> Lattice deform.


Why am I getting an OpenCL driver error with BlendLuxCore when I'm rendering using CPU only?

So, I took a wild guess and installed the OpenCL running environment for my intel CPU only from this site: https://software.intel.com/content/www/us/en/develop/articles/opencl-drivers.html#latest_linux_SDK_release
After I did that, LuxRender works.
If somebody wants to add an explanation about why I needed to do this in the first place (I am partially confused because the LuxRender web site makes no reference to this being a dependency you need to set up before installing), that would be cool. But, my problem is solved, and I'm going to tentatively assume that LuxRender is using OpenCL as a sort of backend to abstract away hardware details like whether you are on a CPU or a GPU and what types.


How to batch remove zero-weight vertices from vgroup?

It turns out that one of the existing weight tools named Clean does all I want, which offers several nice options.

In Edit Mode or Weight Paint Mode, you can find the Weight Tools panel on the Toolshelf in 3D Viewport by pressing T.


How to unlink two objects in the same group?

You must have joined them into one unique object with a ctrl J, so select it, go in Edit mode, select one of the 2 meshes with L and press P (Separate) > Selection


Image Sequence Rendered Purple Despite Being Within Image Sequence Range

Ok, so after a few days experimenting I can confirm this is a bug with version 2.83 and updating to 2.92 makes this blend file work as expected.


The texture is setup correctly, but you have mirror enabled with reflectivity set to 1. This means that the material is entirely reflecting the environment around it, but as the mirror color is black, no light is actually reflected.

If you disable mirror, the texture is visible:

Note that I also set the specular intensity to 0, otherwise the texture is a little difficult to see (but visible).


Render both anims and use VSE. Second strip starts where the first one ends. Render it and its done.


You can certainly do this the other way round and export to After Effects (*.jsx) using the Adobe After Effects plugin but it hasn't been updated for 2.80.

This has been investigated before please see Does Blender 2.8 have a working import-export plugin for After Effects?

The only truly supported format for tracking data import is *.bvh, again via add-on.

You can always modify the jsx script to import instead, but as it stands I donn't know of any native way to do what you ask.

Perhaps look at this addon from the blendermarket

https://blendermarket.com/products/ae2blend


The reason this happens is because you have 'subsurface' modifier enabled.
What subsurface modifier does is basically adds extra geometry to your mesh.

In your case, the type is set to Catmull-Clark which in short will basically smooth out your mesh.

So if you start with a basic cube

and apply the modifier on it, it will smooth it out and it will start to resemble a circle

Now an easy way to make the object look like what you want it to be is add extra vertices where you want the detail. So if I were to add some extra vertices at the corners of the cube it will start to resemble the cube again

Now if you understood this you would have guessed you need to add extra geometry in your mesh at the top of your coffee(or water? depends on how far you are in that tutorial)

An easy way to add geometry to a closed loop is the inset tool(hotkey I), this tool basically makes another smaller loop inside the loop and connects the vertices.


Hiding Entire Panels and Other Elements from the UI

"Whack" em all.

Script will "whack" (unregister) any registered Panel, Menu or Header class that follows the naming convention.
import bpy

classes_to_whack = (
        getattr(bpy.types, p)
        for p in dir(bpy.types)
        if any(
            sep in p
            for sep in ("_PT_", "_HT_", "_MT_")
            )
        )

for cls in classes_to_whack:
    bpy.utils.unregister_class(cls)

More sensible approach here Unregistering panels in python


How to speed up Blender Video Sequence Editor rendering?

Using only colored effect strips and a track of music, I rendered 240 frames resulting in the following export times:
H264 = 16 secs
MP4  = 14 secs
xvid = 13 secs

This tests only the encoding engine. I would also suggest checking the dimensions of the media you are editing with. Any scaling (which the VSE will do automatically) impacts on render time. Try to make this 1:1 with the scene dimensions. Further to the issue of scaling you may want to alter the AntiAliasing value in the scene properties as well. Default is 8 samples.

Finally, in User Prefs, increase the 'sequencer cache' value to maximise your memory usage. And check that you are using the Sound Output Device SDL, in the same panel.


My answer in

[1]How to place any object on the 'floor' of a scene?

My addon append one item in Object>Snap menu


How to find out if the array_index of a fcurve is used

I believe you can do this from the bl_rna array_count property.  For instance on the array modifier, count isn't relative_offset_diplace is.

>>> C.object.modifiers['Array'].bl_rna.properties['count'].array_length
0

>>>C.object.modifiers['Array'].bl_rna.properties['relative_offset_displace'].array_length
3

I came across the same prob with searching for drivers and adding to UI sliders, and went for the try-except, which I also try to avoid.


Weight paint only working on some vertices? [v2.73]

Not sure if this will help, or if you have multiple bones, but the same thing happened to me and I was able to fix it when I discovered that the vertices that I couldn't remove had no weights from any other bone. After adding weight manually from other bones to the area, I was able to remove the weight from the bone I didn't want to affect the area.


How can I bake multiple images (textures) into one image texture? EEVEE

EEVEE currently doesn't support baking, so you would have to use Cycles instead.

Heres how:

Let's start with this simple hybrid texture

Add a new image texture node, click  + New  and give it an appropriate name and dimension.

Select this new node and find Bake Panel under Render Properties. If you cannot find it make sure you are using cycles.

Let's use the Combined Bake Type. Learn about them here. Click  Bake  and wait for it to finish

Connect the Baked Image node into the PRincipled BSDF Node. Its a bit dark since we did not have any lights in our scene. You can even export this baked texture.


There are 8 polygon indices in the list, their elements indices ranges between 0 and 7.

When you removed the polygon indices at index 4, you actually removed the 5th element not the the 4th (because indices starts from zero). Anyway, now you have 7 polygon indices that their elements indices ranges between 0 and 6, you are trying to remove the element at index 7 (8th element) which doesn't exist. Thats why there is an error, not sure why it is fatal though.

So, if you want to remove the 5th and 7th element, remove the element at index 4, then remove the element at index 6.


Not really presented as an answer, but I wanted to add these images to my comment above:

Looks like maybe that part pf the mesh does not completely link to the top bone? Facial rigs often have a primary bone with subordinate children bones that use copy rotation and copy location modifiers to allow motion more complicated than can be achieved by one bone alone. This may not be the answer, but if you post a screen shot of your weight painting, we could tell...

These images are not my work and are used for educational and explanatory purposes only.


Is my AMD Radeon R5 m335 able to render in Blender? Is this a GPU?

CUDA is used on Nvidia Cards. AMD Radeon cards use a different kind of hardware.

You can only use Open CL (and live with its limitations).

The Option "Hainan" is the correct and only option you have.

AMD cards appear in blender with the code name used for the GPUs architecture.

As an alternative you might want to try using other render engines other than Cycles, as explained in this post:
Alternative Render engines can I use instead of Cycles for AMD Radeon GPUs?


Open the Outliner
Switch it's mode to Current Scene
Use the search box to search for ParticleSystem by default (or whichever other name you used, if you manually renamed it)
You object with the particle system should come up in the list bellow
Just click on its icon and it should select the relevant object in the 3D view


How do you create a rounded, inset beveled edge?

Similiar to creating the control edge loops manually (as stated in stauVictors answer), you can create them procedurally with the bevel modifier. Using a bevel modifier before a Subdivision Surface modifier, is common practice to prevent smoothing on sharp edges.

Create a vertex group for the edges, which are supposed to stay sharp and assign the edges to it

Then add a bevel modifier and select that group as the Vertex Group of the modifier. If you use more segments in the Bevel modifier, the following subdivision modifier will have less effect on the beveled segments.

Edit from Coffeehouse's comment: As an alternative to the Vertex Group, you can choose weight as the Limit Method and create Bevel Weights for the mesh.


Repetitive carvings/holes around a sphere

You may do it by beveling the Ico Sphere and using the Solidify and Edge Split modifiers.

Add an Ico Sphere with 3 subdivisions.

Enable face selection mode, press A in Edit Mode to select the whole mesh. Now press Ctrl+B and drag the mouse outwards to bevel it. Select one of the hexagons, go to Select-->Select Similar-->Polygon Sides. Delete selected hexagons with X-->Only Faces.

Add Solidify Modifier and increase its Thickness value. Add the Subsurf Modifier below and give it some subdivisions. Apply the Solidify Modifier.

Add the Edge Split Modifier above Subsurf and set its split angle to 80 degrees (you may experiment with value for optimal result though).

Apply the modifiers and smooth the mesh in the Edit panel of the Tool Shelf (T).

EDIT: After @wchargin 's remark I experimented a bit and tried to solve it in another way.

Added an Ico Sphere with 3 subs, poked it with Alt+P and then beveled some vertices (Ctrl+B, V).

Now the holes have much more dense geometry, which I hope may let them create perfect circles after subdividing.


How do I force the netrender to render everything on GPU?

Network Render plugin does not have this functionality.
Render the scene remotely via the command line. You can run your own script with it to set proper rendering device or render tile-size.
blender -b file.blend -E CYCLES -t 0 -o //file -P script.py

In the script.py:
import bpy

bpy.context.user_preferences.addons['cycles'].preferences.compute_device_type = 'CUDA'
bpy.context.user_preferences.addons['cycles'].preferences.devices[0].use= True

bpy.context.scene.cycles.device = 'GPU'

bpy.context.scene.render.tile_x = 256
bpy.context.scene.render.tile_y = 256

bpy.ops.render.render(write_still=True)

Blender 2.8+
There's an API change for Blender versions 2.8+, it's only bpy.context.preferences (not user_preferences anymore)


Is there any way possible to tail a falling star or comet-like particle?

For the particles:

Start with a sphere
move one vertex far away using proportional editing  so that neighbor vertices are also stretched proportionally

to create the cloud of particles, use 2 array modifiers to create a matrix, apply the modifiers and separate by loose parts

use proportional editing with Random and smooth fall off in order to arrange the particles. Alternatively, use Randomize Tranform.

create a gradient based shader, use Color Ramps to control color, emission and transparency fall offs (don't forget to turn Alpha Blend mode for transparency to work)

For the background:
Create a world shader based on spherical or linear gradient. Use the Vector Mapping scale, position and rotations to control gradient position in the sky.

For animation: Here is the same object used in a particle system (added plane emitter and moved camera around):


how do you subdivision surface, or shade smooth without ruining the object?

These hole cutting tools give an uneven mesh. What i would do is delete those surfaces and make the hole by insetting the surfaces and moving the inset up and down to the holes position. Another options is to loop cut around the hole and face them through to each other. PS to get that square to a circle subdivide it and press shift-ctrl-s and scale it to s sphere


Can I use something similar to the ParticleInfo Node but for meta objects?

You could color your Metaballs easily with the Point Density Texture/Map. I recently found it works also great on surface coloring just like the volume coloring. You could set the Radius in the Point Density settings high enough to reach the surface of the Metaballs and it should work properly.

EDIT:

I just tried it myself and it actually works. When you use the Point Density in the Material of the Metaball you have to select the Object with the Particle System on it and make the Radius high enough. You can also select if you want to know the speed or the age of the Particle. Also Cubic Interpolation is much more beautiful in my opinion so select that.


Modelling for Unity, should I remove intersecting parts?

If the pieces are two seperate objects, press Ctrl + J to join them, that is better for performance, because it reduces the drawcalls from 2 to 1. If the pieces are one object with two intersecting pieces, this is fine, in fact, it is better than wasting resources rendering hundreds of faces when you just need 10. Sure, if you zoom in really, really far, the intersection won't look too pretty, but how often do zoom that far in on the roof of a house?


Render of Planet Earth in Blender Render and Cycles

Cycles is capable of utilizing physically-based rendering techniques, but that doesn't inherently make every render appear photo-realistic. See How is Cycles different from Blender Internal?

To get a nice atmospheric scattering effect in cycles, I'd suggest wrapping your earth sphere in a slightly-larger sphere with a volumetric material such as this:

Result:

Note that these values are arbitrarily hand-picked based on what I thought "looked nice". If you are after accuracy you'll probably want to do a bit more research than I did ;)

It could use some tweaking, but it does look somewhat similar to actual photographs of the earth:

Note that in the above setup the atmosphere is a constant density. The real atmosphere gets less dense higher up, creating a subtle falloff. This is pretty easy to simulate with a spherical gradient texture, but will vastly increase render time.

If you don't see the edge of the atmosphere very close up in your render, simulating this may not be necessary.

In response to the edits to the question:

To get rid of the grid-like pattern, add a subsurf modifier to the atmosphere sphere and increase the number of subdivisions until it's no longer apparent.

The reason the earths atmosphere appears bluer at the edges is because light which travels farther through the atmosphere is more likely to be scattered off air molecules. Since rays closer the edge of the atmosphere which travel farther through it, they appear bluer:

Keep in mind that thickness matters a lot with volume rendering, so another thing you can tweak (in addition to the density etc.) is the scale of the atmosphere object (adding more or less atmosphere on top of the ground)

Here's the .blend of my setup:

Textures intentionally omitted

Note that everything is just eyeballed; nothing is based on real-world data.


Customizing array objects with shared material

Figured it out. In object mode, select the objects that need to be unlinked. Press U, select Materials+Tex.


Wavefront export with [Vertex/texture-coordinate/normal] face definitions

There are several objects included in the one file, all vertices listed are numbered in the order they exist in the file, each object then uses a range of these vertices for it's faces.

You will find that the objects and it's related items in your exported file will be in a different order than the original, therefore each object uses a different range of vertices. You should find that the total number of vertex lines, face lines etc. should all match up, just that each object is using different numbers.


I get this weird white line as I zoom out a view

Most probably the edges of your UV-map faces are to close to the edge of the corresponding texture imagery underneath.
As you can see in the four zoomed-in UV Editor windows, the UV-map is neatly within the borders of the blue square in the texture.
But because the texture is blurred (or smoothed), the orange background color bleeds into the UV-mapped area. This causes the plane in the 3D Viewport to have blurry orange edges.
The texture is blurred because the top entry on the Image Texture node is set to Linear. Note how a single green pixel in the bottom right corner is blurred.

To fix it you can simply move the edges that suffer from the color bleeding away from the border and away from that color.

Alternatively, if you set the top entry on the Image Texture node to Closest, it will also solve the color bleeding problem, but you will get a pixel perfect display of the texture on your material and corresponding model, as commonly seen in Minecraft models and textures. (The single green pixel now looks like a pixel)


Try changing the Initial Orientation in Rotation settings as indicated by the arrow. If the setting does not work try the other settings for Initial Orientation. One will work. You may need to go to the start of the particles frames and move through frames to see the result. The particle system display may need to calculate and play catch up.


How to copy/paste a baked sound f-curve?

I would suggest you bake the sound into one distinct property, like the scale of an empty you add for that purpose, and use it to drive all places where you need the sound f-curve. This way there is no duplicated data, and if you have to edit or change the sound you won't have to copy a bunch of animations every time.

You can also search for "bake action" from the spacebar menu to make the baked action into normal keyframes, and copy them around, but the driving method is better in my opinion.


Why can't I create a pipe from this curve?

For this setup to work, your circle has to lay flat on Z axis.Like this:

And it has to have this rotation applied, so you can rotate it in object mode and press Ctrl+A and choose Rotation or rotate it in edit mode. It will have exactly the same effect.


Yes, Blender is absolutely capable of doing this.  The feature you are looking for is called dynamic paint.

To do this simply select the object you want to deform, go to the physics tab, click on dynamic paint, and choose canvas.

Then just scroll down to the dynamic paint advanced rollout and choose displace under surface type.

Next, select the object you want to use to inflict the deformation and set it as a dynamic paint brush (just select brush instead of canvas).

Then you can animate the brush object to scratch across the canvas object and it will deform it.

A few tips for using dynamic paint:

You will want the canvas object to have plenty of subdivisions so that it has enough geometry to get deformed.
You may want to enable anti-aliasing and add some sub-steps on the canvas object for a smoother deformation, particularly if the brush object is moving fast.  This makes Blender sample the motion of the object between frames for smoother painting.


How to make an army-style march with particles following landscape?

Create a flat Lattice and Shrinkwrap it to your terrain. Make sure it has enough divisions to conform to the terrain accurately.

The reason for using a Lattice is that directly Shrink-wrapping a mesh against another mesh when animating will create jittery snapping artifacts as verts latch on to other verts, while a Lattice on the other hand smoothly interprets the curve and makes it usable via the Lattice Modifier.

Create a particle emitter plane and put a Lattice Modifier on it that uses that Lattice.

Animate the emitter plane traveling across the Lattice.

The original animated characters must be on an enabled layer or their animation will not be calculated for their particles.

With just one character model used, the marching looks too uniform. But this can be remedied by using a group instead and having each model in the group have variation in physical appearance and walk cycle.

There's just one more issue to address. You may have noticed some of the troops are scaling the steep hills too quickly. Others have limbs intersecting with one another. These problems can be fixed by using shape keys to deform the vertex positions of the emitter mesh to steer troops away from obstacles:

An alternative to using Shape Keys is to Hook an Empty to their emitter vertex and control them using that. The Empty will need to be parented to the emitter mesh to move in relation to it.

Note that these techniques require the particles to be set to emit from verts, not faces.


If you encounter any problem toward Undo system, please help to file up that bug to the bug tracker in Blender develop. There is a new undo/redo system been adopted due to the old one was bulky in some situation.

A quick way to fix your strange behavior is to use old system instead of new one:
By checking Developer Extras in Preference-

And choose Experiment panel and check undo legacy


How do I select things behind/near the gizmo?

I had the same problem and the solution is to go to

Edit > Preferences > Keymap then select Drag under Activate Gizmo.

and it should work.


Your objects are mostly flat, so the best solution seems to unwrap it with "Project from view" with viewport looking strait perpendicular to the surface. It will give you nice square map, which will allow you to use your reference directly. Maybe with some UV expanding and texture painting (with texture in stencil mode) on the most protruding parts.


Python select specific edge loop based on diameter and height

On creation

Started as a comment and became an answer

  Could you add some context on how the mesh came to be, are you
  creating from scratch with a script.

If using bmesh operators often the new geometry is returned, for example making question model from  a circle primitive using the extrude and inset operators.

Example using bmesh to add a cylinder bmesh.ops.create_cone(...) find the top face, then inset in and up.

import bpy
import bmesh
from mathutils import Matrix
me = bpy.data.meshes.new("Wedding Cake")

segments = 16 #oops got cut

bm = bmesh.new()
bmesh.ops.create_cone(bm,
        diameter1=2,
        diameter2=2,
        cap_ends=True,
        depth=0.5,
        segments=segments)

top_face = [f for f in bm.faces
        if len(f.verts) == segments
        and f.normal.angle((0, 0, 1)) < 1e-5]

ret = bmesh.ops.inset_region(bm,
    faces=top_face,
    thickness=0.5,
    #depth=0.1,
    use_relative_offset=True,
    )

ret = bmesh.ops.inset_individual(bm,
    faces=top_face,
    thickness=0,
    depth=1,
    use_relative_offset=True,
    )

bm.to_mesh(me)

To continue the "hard sell on bmesh over bpy.ops" what if we want to make something like this

is a matter of extending above to inset the faces returned from the inset operator

for f in ret["faces"]:
    ret = bmesh.ops.inset_individual(bm,
        faces=[f],
        thickness=0.4,
        depth=0.4,
        use_relative_offset=True,
        )

or instead with

bmesh.ops.extrude_individual(bm,
        faces=ret["faces"])

Another example, adding circles and bridging edge loops (ribs)  As could be done with prior, some data is used and looped.

import bpy
import bmesh
from mathutils import Matrix
me = bpy.data.meshes.new("Wedding Cake")

segments = 16
steps = ((0, 1),
        (0.3, 1),
        (0.3, 0.7),
        (0.5, 0.7),
        (0.50001, 0.4), # gltches on same
        )

bm = bmesh.new()
def create_circle(h, radius):
    ret = bmesh.ops.create_circle(bm,
            radius=radius,
            segments=segments,
            matrix=Matrix.Translation((0, 0, h)))
    return list(set(e for v in ret["verts"] for e in v.link_edges))

ribs = [create_circle(h, radius) for h, radius in steps]
for i in range(1, len(ribs)):
    bmesh.ops.bridge_loops(bm,
            use_pairs=True,
            edges=ribs[i-1] + ribs[i],
            )

bm.to_mesh(me)

Nothings happening

  what version can this script running on? i try 2.81 but does not
  produce anything

Note script only creates a mesh, the data part of an object, we only see a mesh if it is assigned to an object.  To assign in UI (image above) go to properties data and change the linked mesh..

Or via python, create a new object using the mesh and link it to the context collection.  Append following to scripts above

ob = bpy.data.objects.new("Wedding Cake", me)
context.collection.objects.link(ob)

or if using in a create mesh operator (self)

object_data_add(context, me, operator=self)

Selecting the verts

For finding from height and radius, and assuming the origin (0, 0, 0) lies on symmetry axis (0, 0, 1) ie the z axis , would look at the distance of verts from (0, 0, h)  (v.co - Vector((0, 0, h))).length

A vector length test searches within a sphere of influence. Could narrow down further by looking at z component, I go old-school here and look for within a tolerance, abs(v.co.z - h) < TOL where TOL = 1e-5

For really large meshes instead of sorting based on distance, could use mathutils.kdtree to find closest.

Utilize the ngon

For this particular example the inner loop is the verts of the ngon.

Here is an example that finds the ngon whos face is closest to (0, 0, h) and selects its vertices.

Test script, Assumes mesh in edit mode, no selection.  If run on default cylinder selects verts of top face.

import bpy
import bmesh

from mathutils import Vector

context = bpy.context

ob = context.object
me = ob.data
bm = bmesh.from_edit_mesh(me)

h = 1
radius = 1
eps = 1e-05

ngons = [f for f in bm.faces if len(f.verts) > 4]
# sort by distance from (0, 0, h)
ngons.sort(key=lambda f : (f.calc_center_median() - Vector((0, 0, h))).length)
if ngons:
    for v in ngons.pop(0).verts:
        v.select = True

bmesh.update_edit_mesh(me)

The edgeloop of the ngon would be ngon.edges or l.edge for l in ngon.loops

can grow the selection to next loop, will be the edges in  e for f in edge.link_faces for e in f.edges if not any(v.select for v in e.verts).


How do i bake a material onto an image texture?

Here I added a new image node with a large generated image texture, disconnected from the node chain. I added an Emission node to feed my adjusted painted texture into instead of the diffuse shader so that I could bake the Emit output and get the same color info without any shading added.


Why is it when I change my animation and delete keyframes it deletes keyframes from a different animation?

What's happening is not what you're describing, actually you're completely misguided because one of your window is completely collapsed, so when you think you're deleting the keyframes of an action you're actually deleting the keyframes of another. So first of all, uncollapse your window, and now you'll see the action that is really selected:

To delete actions, there are several ways, one is to go to the Outliner, select Blender File in the dropdown menu, unfold the action menu, select and right click Delete. You can also shift click on the X, the action has a 0 in front of its name, meaning that it doesn't have any user anymore, it won't be here when you'll reopen the file. You can't delete actions with the NLA.


Why do I have the 2.80 API on blender 2.79

Blender version 2.79b is the one that you can download when you click Download Blender at the top of the download page at https://www.blender.org/download/ at the time I am writing this (05-01-2019).

If you however choose to scroll down to the bottom of that page and click the red button 'Latest Experimental Builds' in the section with the red background and a clear disclaimer in English:

 you will be downloading experimental builds (not unlike the disclaimer states) and may try latest changes that may include changes to the Python API.