How to get rid of unnatural green glare from grass?

Limit light bounces

The green colour comes from the light that bounces on the grass and the grass planes. As no direct light hits that surface, it is been colored by the indirect light only (which in your case is green). Because the walls are almost white, the effect is even stronger.

This is a physically based behaviour. You can get more information by searching about "Color Bleeding".

Notice how the faces of the cubes inside the cornell box that don't get direct light gain the tint of the wall they are facing.

Try to enable diffuse direct&indirect render passes and examine them and dedermine where the green comes from.

Anyway you can get rid of that by for example limiting the number of light bounces of the plane material:

The ray depth node will assign an empty shader to the material if it has done more than 0 bounces (direct light).

You could also work on the light path bounces in the render tab, but using the material nodes will give you full control on the single material, while preserving physically based behaviour of others.

If you don't want to leave the physically based way, I would suggest to lower the saturation and the value of your grass plane and maybe make it less green, more brownish, as it would be in a real world. This is probably the real cause it looks so unnatural.


How to change modifier keys for navigation?

You can change default keyboard shortcuts in the User Preferences - ctrl+alt+u under Input tab:

Note that you can search for the keys currently used.

I would have to strongly recommend against that. Especially if you are a new user. Blender has an extremely complex hotkey system and you are likely to cause serious problems for yourself changing it. You are likely to break continuity and make some important functions inaccessible unless you are an experienced user familiar with all Blender's keyboard shortcuts and know exactly what you are doing.


How to add different Gravity velocity for different objects?

I've not used Cycles but the "Damping" setting in the physics properties (see pic) will slow down a particular object where it's used and leave the others alone.   The cube has damping applied (bottom right in the settings) and the cylinder doesn't.  You can see that they're falling at different rates.

The view is from underneath the grid -


Script for splitting a mesh into n components along z axis

My guess is you have scaled the mesh and haven't allowed for local space for the bmesh operator(s).  Eg if you add a prim cylinder and scale it by z 10 fold, it's local space will still range between -1 to 1 for z for each vert coord. Running the script will only give the 0 plane cut.
Multiplying the plane location by the inverse of the objects matrix world will put the cuts into local space.
import bpy, bmesh
from bpy import context as C
from  mathutils import Vector

# matrix world inverse
mwi = C.object.matrix_world.inverted()
bpy.ops.object.mode_set(mode='EDIT')

bm = bmesh.from_edit_mesh(C.object.data)
geom = bm.verts[:] + bm.edges[:] + bm.faces[:]

for i in range(-10, 10, 2):
    j = mwi @ Vector((0, 0, i))        # Blender <3.90: mwi * Vector((0, 0, i))
    ret = bmesh.ops.bisect_plane(bm, geom=geom, plane_co=j, plane_no=(0,0,1))
    bmesh.ops.split_edges(bm, edges=[e for e in ret['geom_cut'] if isinstance(e, bmesh.types.BMEdge)])

bmesh.update_edit_mesh(C.object.data)

bpy.ops.mesh.separate(type='LOOSE')
bpy.ops.object.mode_set(mode='OBJECT')

Alternatively apply scale before running splits.
bpy.ops.object.transform_apply(scale=True)


Let me unpack this one by one :)

1. Fill caps
You need to check Fill Caps in Geometry > Bevel > Fill Caps

2. Overlapping geometry
This is a result of beveling multiple curves into one point.
You'll have to manually clean it up, or use the Boolean modifier, etc.

3. Too many faces
To adjust the amount of faces change the values in Shape > Preview/render resolution.
You can do this for both of your curve shapes.

Here is the edited .blendfile


Particles per face are either too many or not enough

You could emit the bricks from vertices, make sure that you emit exactly the same number of particles as the emitting mesh has vertices (121 in this case):

from verts

Emitting from faces with the grid option selected creates a box of emitted particles.

from faces


Mirror selection but maintain current selection

This may not be the best solution, but I have found that it works. Start by going into Edit Mode, make sure you've opened the Object Data tab of the Properties Panel (1), then create a vertex group for the initial selection of vertices. Create the new group by pressing the + sign to the right (2), and include the selected vertices by clicking the "Assign" button (3).

Next, while still in Edit Mode, locate the "Select" Menu at the top left of the 3D-View, and open it to choose the "Mirror Selection" option at the bottom of that menu.

Finally, go back to the Vertex Group you created and press the "Select" button to get back your original selection.


Math nodes on object's coordinates
There are several approach you can take, the easiest is to build a shader that is capable of recognizing the isolines (lines that have something in common, the same Z in this case).
Start by adding a texture coordinate node. We'll use the object coordinate (the position of it's origin in this case) as a starting point.
Whit a separate XYZ node we isolate the Z channel:

Then we use the math "modulo" node to subdivide the Z channel in several segments, and the math "compare" node to extract an interval from each segment (you can use a color ramp if you want a smooth edge).

We basically obtained the lines, now we just need to use the results as mask for the mix shader node between our two shaders.


First of all, you need to apply scale and rotation to all your objects

shift + a

You can't have any scales that are negative, also this is just a general practice I would advice you before rendering.
Note that sometimes you have to check if your object face normals are not inverted after applying a negative scale.

My computer has issues rendering right now but this was my result:

I also set the sun strength to 2.5, but that is up to you of course.


How can a cloth simulated sail be prevented from flying away?

A few vertices should be added to a vertex group:

this vertex group is assigned in the cloth settings with ticked Pin option.

Besides that I found that a vortex works better than plain wind force.


How to erase any residual keyframes from a .blend file?

I got rid of it but using vers 2.77a.  Let's hope it works in your version...

-===============-

The problem was a grease pencil hangover and it's slot that was still active.

Procedure to rid yourself of that pesky keyframe...

Zoom in a bit to see the G/pencil drawing south of the grid.

Goto Edit mode and press A.  The GP points will all hilight

Delete them with X.  (points)

Press N to open the 3D viewport's properties and delete the Grease Pencil slot.

Untick the grease pencil's box.

The keyframe will still be there.

Save the file as something else and the keyframe should disappear when the 3D widow updates.

If not exit Blender and reload.


The implementation of the correlated multi-jitter can be found in blender/intern/cycles/kernel/kernel_jitter.h . The functions are called cmj_sample_1D and cmj_sample_2D. The code is based on Andrew Kensler, "Correlated Multi-Jittered Sampling", Pixar Technical Memo 13-01, 2013.
Here is how you can find this yourself:

Enabled Python Tooltips in the preferences (Edit > Preferences > Interface)
Hover over the sampling pattern drop-down in the UI until the tooltip appears. Take note of properties name, it is sampling_pattern.
Search for sampling_pattern in Blender's code. This can either be done in your local copy of the code or online through Blender's website or its GitHub mirror.
Find the code that implements the property first and try to figure out how it is used. You will notice that the property can be found in blender/intern/cycles/blender/addon/properties.py and the values that can be select for it come from enum_sampling_pattern.
The type that defines the enums that could be assigned can be seen in blender/intern/cycles/render/integrator.cpp and here. The name of the enum is SamplingPattern. The entry SAMPLING_PATTERN_CMJ is for the correlated multi-jitter.
Searching for the occurrences of SAMPLING_PATTERN_CMJ shows that it is used in blender/intern/cycles/kernel/kernel_random.h. The functions to compute the correlated multi-jitter are called cmj_sample_1D and cmj_sample_2D. Both are implemented in blender/intern/cycles/kernel/kernel_jitter.h .


If you are trying to achieve an effect similar to the one you get with the Blender internal renderer, you can use the Wireframe node to separate edges from the rest:

The white (1) regions are at the specified distance from the edges, and the black (0) regions are not. You can pass these values to the mix shader to use separate shaders for these two regions:


How to set all selected vertices to height of another vertex?

One way to do this is to set the pivot point for transforms to be the active element, by choosing Active Element for the Pivot Point in the bar below the 3D View:

If you have Pie Menus enabled, you can press .>7 instead.

Then select all the vertices you want to affect making sure that the one whose height you want to copy is the active one (i.e. select it last) and just Scale in the Z axis direction to 0, by pressing S, then Z and then 0.


How to make an object accelerate and *then* rotate at a constant speed?

The tangent to the curve reaching frame 50 must be exactly in line with the linear progression after frame 50. Also the 1-50 curve must also stay to the left of the linear ascension otherwise it will look like it accelerates before getting to the linear part.


You're currently baking the high-poly object to itself, which will give weird result as the surface that will scan the high-poly is the high-poly itself, you'd better bake the high-poly to the low-poly:

Select the high-poly, shift select the low-poly
Enable Selected to Active
As the high-poly is a bit bigger give it a bit of Extrusion and Ray Distance, not too much, the value is in scene units

What it gives:


Shapekey range animates in viewport but not in render

It is a bug in 2.90 (and 2.8x). It is fixed in 2.91 alpha


TinyCAD is available through the Right Click context menu in Edit Mode.


3D manipulator widget in multi-selection does not appear

Press N in your 3D view, the 3D view properties panel will display on the right, you can see that some of your objects Transform parameters are locked, you can't see any manipulator if at least one of the objects you select has these transformators locked.

Those parameters are also available in the Properties panel > Objects > Transform Locks


You should to set pictures for Udim .
Read this Link


Change the color of the default (no) material (Cycles)

Open Blender, go to the Materials tab from the drop down select Material. Make your required changes, you code enable Nodes and do something really complex or just change the colour. Then go to the File menu and Save Startup File.

Now when you open Blender the default material will be your custom one.
You can also do this to have a default background.

Alternatively, you can set a single material for all objects from the Render Layers tab. Handy for Clay renders.


When I render on cloud, there is error that cant read files of addon

File → External Data → pack all into .blend


"Main scale" control on a material from Poliigon Material converter

The Add-on is responsible for adding this field there. But it only gets drawn if a special property, managed by the add-on, is present in the material properties. These custom properties don't get copied over when you duplicate a material.
Basically this is just a shortcut to the scale values of a mapping node inside the material. I think it is a bit convoluted for what it does, but you should contact the support if you want to make them aware of this limitation.
Digging into the add-on files I found this:
if mat and mat.pmc_matprops.workflow != '':

        # get the mapping nodes, if found
        main_map = None
        for n in mat.node_tree.nodes:
            if 'main_map' in n: # ie n['main_map'] exists
                main_map = n

        if main_map:
            row = col.row(align=True)
            if hasattr(main_map, "scale"):
                row.prop(main_map,"scale", text="Main scale")
            elif 'Scale' in main_map.inputs:
                row.prop(main_map.inputs['Scale'], "default_value", text="Main scale")

Explanation :
On the first line the method checks if the material has a custom property named pmc_matprops. I believe it is added by the add-on when first instantiating the material. When you duplicate the material, the property doesn't get copied over.


Normal maps do not control the lighting of a surface, they only define surface facing direction. It is impossible to store light or shadow information in a normal map. You should not attempt to judge the information in a normal map based on what you see. It is not a shadow, these simply are numerical values that happen to be lower. You should look for the issue in your lighting or geometry if there are shadows where they should not be.


This 3 modifiers produce similar effect:

We have remesh for create huge amount of square faces, next adding randomness by displace with noize texture, and decimate for creating big irregular faces. You can tune all settings to get different results.

Maybe, instead of creating geometry, try to use texture (as you suggest voronoi):

I use node group from here: Voronoi Cracks Fac?


How do you Disable Mipmaps in Blender 2.80

I just figured it out.  You have to set the interpolation on the texture to closest, and under the render panel, film, you need to set the filter size to it's lowest setting.


Using "Material Preview" HDRI in Renders?

This is possible, but at the time of writing it's not a one click solution.

First you need to setup your world to use an environment texture and then load the same HDRI that is used in Look Dev mode. The HDRI can be setup either in the World tab or in the Shader Editor using nodes.

Blender 2.80

Blender 2.81 and later

The HDRIs can be found in Blender's installation directory:

[Install dir]/2.80/datafiles/studiolights/world

In Blender 2.81 you can use the same HDRI from Material Preview mode (formerly called Look Dev) for lighting in the Rendered preview mode in the viewport. Switch to the Rendered mode by clicking on its icon, then open the Viewport Shading options and disable Scene World to ignore the settings from the World tab. One of the HDRI presets can then be selected.

However for the actual rendering you will still need to set it up as described above. In case you've already done that, the Viewport Shading options can be left at their default values with Scene World enabled.


Does a separate GPU for CUDA work with main AMD card, in Cycles?

Silly me, i completely forgot about the option in the renders tab, i thought the user settings was enough. Anyway it does appear to work, fur mark does show the GPU heating up.

It isn't very useful due to it's low memory and little processing power, but being on a separate GPU i can render lesser projects while doing other tasks.

I did NOT have to enable Experimental Feature Set. do not know if it changes anything.

Thanks everyone!


How to select objects and join them with Python

Here's the pseudo code:

make sure nothing is selected to start off.

for every empty that has children:
    1. select all children of the empty
    2. set first child to active_object (or any child)
    3. invoke a bpy.ops.join
    4. deselect everything

Because you can't join anything to an Empty, You have to programmatically set a Mesh Object to be the Active Object then join other selected mesh objects to it.

Here's the python:

import bpy

# get the list of empties that have children
empties = [e for e in bpy.data.objects if e.type == 'EMPTY' and e.children]

# we need to deselect everything first
bpy.ops.object.select_all(action='DESELECT')

for empty in empties:
    for obj in empty.children:
        obj.select = True
    joiner = empty.children[0]
    bpy.context.scene.objects.active = joiner
    bpy.ops.object.join()

    # deselect everything before the next iteration
    bpy.ops.object.select_all(action='DESELECT')


How do you make grouped objects a focus point without moving the camera?

Add an empty and place it where you want to focus.

Set the empty as the focus object and lower the value of he F-stop to reduce the depth of field.

You might need to increase the number of samples to deal with noise.


Moving Finger in blender Moves the other part of hand?

The problem has to do with the vertex groups the bones influence.

When you parented your mesh to your armature blender created a vertex group on the child mesh for every bone in the armature.  Looking at the bone names you can see the bone with the problem is named "Bone_L.009".  You'll find the corresponding vertex group here:

Select the "Bone_L.009" vertex group and go into Weight Paint mode.

The problem is pretty obvious: the bone has influence on other parts of the mesh than the intended "finger" (you can see that there is a green area also on the other "finger", thus it is influenced by the same bone).

To correct, in the weight paint brush options set the Weight to 0 and then paint over the problem area of the mesh.

It should look something like this where you're done:

The fingers will now move independently.


I think I fixed the issue by substituting the last Mix node with an Alpha Over node. That appears to have gotten rid of the holes, but I don't know why. If anybody's got either an explanation, or another fix, I'd love to hear it.

Thanks!


Bad Topology got after applying modifier

Your topology looks decent.
I'm pretty sure your array modifier didn't match start and end 100%. That created an overlap which you see in your 1. screenshot. Repairing this is tedious, it would be much simpler to go back to before you applied the array and fixing it in the base shape. If you use a segment of a circle or a sphere and then rebuild the circle/sphere from the modified segment with a circular array, make sure not to touch the outermost vertices, as they have to align perfectly in the end.


That's normal, meta strips always keep the content as it is.

If you want to cut both audio and video at the same time, you can use the select linked time mode to select them both. It only works if the audio and the video strips are the same length. If they aren't, just cut the extra footage on the longer strip, and it'll work. By default, it's done by pressing Ctrl + Select Mouse (Ctrl Right Click).

Then you just have to cut like usual.

This keymap item can be found under Sequencer / Sequencer (Global)


You have 2 mistakes.

1) You Muted Render layer In Node editor.

So go in Node editor, Compositing mode, select Render Layers Node and unmute it using M

2) You hide all objects in render. Click on camera icon to make them visible in render:


Render Vertex Colours in Blender Internal

You enable the option in the shader panel for Vertex Color Paint.


Can Blender save Rendered image periodically

There is a trick that you can recombine images in post editing with blender.
Then you can combine 10 images or so, (using animated seed settings).

So you render a still image as animation images with lower sample rates and recombine them. it takes a bit of manual work to recombine, render speed is slightly lower (bhv rebuilds between frames). for the rest doable.
in the beginning some people hoped to reduce noise.

or in theory one could use this method to increasingly improve a real animation render if you store the images in different folders (by some scripting).

But you might also check the latest blender builds and the denoiser, unless you do a lot of diamont /glass reflections such a sample settings can be decreased a lot.

There is a addon/script that does this
http://adaptivesamples.com/2013/07/22/progressive-animation-render-addon-and-image-stacking/

Most of all though i recomend to review your render settings, today a fairly reasonable render can be achieved with proper render settings:
https://www.youtube.com/watch?v=8gSyEpt4-60


How to pass a property from popup to execute

invoke_props_dialog() opens a "blocking" popup, it won't call execute() with the updated values until user confirm with OK button.

Use invoke_props_popup() instead, if you want to immediately re-run the operation:

import bpy

class CurveOutline(bpy.types.Operator):
    """Curve Outliner"""
    bl_idname = "object._curve_outline"
    bl_label = "Create Outline"
    bl_options = {'REGISTER', 'UNDO'}

    outline = bpy.props.FloatProperty(name="Outline", default=0.1, min=-10, max=10)

    @classmethod
    def poll(cls, context):
        return (context.object is not None and
                context.object.type == 'CURVE')

    def execute(self, context):
        createOutline(context.object, self.outline)
        return {'FINISHED'}

    def invoke(self, context, event):
        return context.window_manager.invoke_props_popup(self, event)

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

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

if __name__ == "__main__":
    register()

Added a check for context.object is not None to ensure the operator isn't run with no active object and replace selected_objects[0] by object, as it's not the same. If you intended to work on multiple selected objects, get all selected objects and remove the active one from list to separate them.


Bases on other questions, I think your problem is that you haven't enabled the meshes for render. At the top left, there should be a list of meshes. Click the camera next to the name of the mesh so that its like this:

And you should be fine. :) (Also, add some more lights to your scene so the meshes aren't black)


The object has no UV map: Blender does not know how to map the texture.
You can either add a "texture coordinates" and change the "image texture" to "box" and tune the "blend" value:

Or create a UV map.


Here is a quick try with bones, I guess it's the right solution, but you'll probably need to clean the topology:


Use the regular class definition scheme as shown in the TextEditor Python Templates -- unless you have a good reason to use a class Factory.

As Sambler shows in the new answer to the previous question: You can do this much simpler with standard class definitions -- the use of the "class Factory" was not appropriate in this scenario because it wasn't the least complicated solution.

However, to answer this question anyway; the make_panel function is what we might call a "class Factory".

Positive

It generates unique classes on the fly, requiring little code to  individualize each class. Especially useful if you need many classes which differ only in small but important ways.
This avoids explicitly writing the full class out in code for every class if you just need to change a couple of lines or functions per class.

negative

The downside to a class factory is it becomes tricky to reason about the code, especially for newcomers. If you don't know how to introspect a class it becomes a bit of a black-box.
classes generated this way must be registered with bpy.utils.register_class(...)

register_module(__name__) won't find these classes automatically.

How to use such things correctly is better discussed on a programming QA like StackOverflow. See this question / answer " How can I dynamically create derived classes from a base class " . If that question is over the top of your head, probably wait till you get more Python experience before using the code.


The "distance" between them may be the same in the direction of duplication (ie. global), but not in the direction of extrusion (ie. the normals of the curve).

One solution to fix this is using the same curve to deform all your planes, just give each of the planes the right offset in object mode.


Rendering in GPU and CPU in different instances at once

Yes, mixing CUP and GPU rendering on two instances should be faster if you have enough memory to fit two instances of the rendering job. Just make sure you set the CPU rendering instance to a lower priority (using the task manager on Windows, or nice with Linux) so that it doesn't take any CPU resources away from the GPU instance. Otherwise the GPU instance might be starved for instruction from the CPU and cause a slowdown.

With Blender 2.79a, a built-in mixed CPU/GPU rendering mode is also available. Just need to enable it from the User Preferences:


You can copy the startup.blend file from your old blender config directory to the new one.

Example:
(on most linux distros) ~/.blender/2.69/config/startup.blend -> ~/.blender/config/startup.blend.
On Mac OS, it'd be in ~/Library/Application Support/Blender/<version>/config. Not sure about windows.

The only other things that seem to be there are user-installed add-ons (in scripts rather than config), bookmarks (config/bookmarks.txt) and recently opened files (recent-files.txt). You should be able to copy those without an issue.

For the startup blendfile, it's probably a good idea to save your settings after having started up, or to just continue doing it as you wrote in your question, to make sure that the blendfile is actually of the right version. Shouldn't make a big difference what with it still being a blendfile and the great reverse compatibility in blender, but you never know!


There is no magicaly appearing checker board ;)

The UV/Image Editor has the feature to load images from disk but also to create new ones. And one of the new image templates is a checkerboard, called UV Test-Grid. Your tutorial guy just had one already created.

Click on Image -> New Image and choose UV Test Grid and it should appear!

To also see it in the viewport choose texture as your view options and assign the newly created uv testgrid texture to your object (in the materials tab of your object)

Since thise is a UV Grid, you should have your object UV unwrapped in order to see it. So if the object stays gray you have to unwrap it first. If the texture then looks screwed up you have to properly uv unwrap your object ;) There are many tutorials out there that show you how this is done.

Create new image:

Choose Generated Type "UV Grid":

Assign the new image as texture of your object:

Make sure youe selected Texture in your 3D View:


Download this addon
Blender > File > User Preferences (Ctrl+Alt+U) >

Add-ons Tab > Install from file... > Choose the downloaded file > Save user setting
Input Tab

  Save user settings > Close User Preferences

Now in the viewport you can use

touchpad > drag = rotate
touchpad > Alt+drag = moving
touchpad > Ctrl+Alt+drag = zoom

In the Node Editor you can use

touchpad > Alt+drag = moving
touchpad > Ctrl+Alt+drag = zoom


Applying a material to a model which has preassigned materials

Select your object. Tab into edit mode.

Hit P. It will bring up 3 options

Selection
Loose Parts
By Material

Since you are asking about adding materials to different parts, you probably don't already have them.
If th mesh isn't solid (i.e., body, head and hat don't share vertexes) take the "Loose Parts" path.

This will turn each part of the mesh into a separate object. They can be colored separately.

alternately, you can mouse over a part of the mesh and hit L. follow this answer to color the selection.


it's because of your (different) blend mode/shadow mode:
set all to

alpha blend
alpha hashed

and it works.


Why do materials & textures look different in material mode & Cycles render mode?

Cycles is not using the UV map.
add a Texture coordinate node and connect the UV output to the Vector input of your image texture.


Problems with scaling meshes. Unwrapping transforms the scale back to normal

It's not that UV unwrapping transforms the scale. It just discards previous UV mapping and creates a new one for selected faces. And it tries to take as much texture as possible (if it won't cause stretching), so in your case it just puts 4 corners of a square face on 4 corners of a square texture. I don't know why you keep unwrapping the mesh after scaling it, but either way you should consider using scale vector of a mapping node:


Summary
This is easily done with the camera or window texture coordinate in cycles, but you could also easily do it with uv project instead.
Final result:

1. Modeling
Modeling this is obviously very straightforward. Add a plane, then go into edit mode and add a bunch more! Vary the heights of the planes so that they occlude each other, and spread them out in a visually pleasing manner. This shouldn't take more than 2-3 minutes to finish.
In the GIF, after I finish this modeling (which I skipped most of to save time), I unwrap it using "project from view" while in an overhead view. Depending on the image you are projecting onto, you may need to scale it to make it more square in the UV/Image Editor.

2. Material Setup
The material setup is likewise simple. Add an image texture node that uses a UV map node to provide the color input of a diffuse shader.
UVMap --> Image Texture --> Diffuse --> Material Output

3. Lighting
a. Setup sun lamp
Add a sun lamp and rotate it to get the nice shadows you would expect. In the GIF, I also change the world color to something close to white for increased ambient light (this is more personal preference).

b. Setup backdrop for those shadows
Add a plane behind the model that can receive the shadows from the planes that are in the model.


Those objects are labeled in a way that suggests they are shape widgets for the bones. Without these, the bones will look like the normal octahedral shapes (or however your armature is displayed). You could delete them if you really wanted to, but it's easier for those working on the file if you don't, especially us animators. It's very easy to get lost in a complex rig.

I would just parent them under an empty to clean up the outliner, if that's what you're really after.

The only parts I would delete are the lights, because those should be done in a separate file after animation is complete.


Shortcut to quickly add texture in the shader editor doesn't work?

Make sure you have the Node Wrangler add-on enabled.


How can I reload a UI operator instead of creating a copy of it when I run a script?

When you add or alter something in your adddons register() function you also need to undo that change in unregister(). For your menu item that means adding bpy.types.INFO_MT_add.remove(add_it)

The other issue you have is running the script in blender's text editor. When you do this the code after if __name__ == "__main__": will be run, if you want to test your addon like this then add an unregister() call before the register() call. You will want to put the unregister in a try block to catch unregistering before the first register.

Blender's addons are sometimes easier to test if you save the file in your addons folder and disable/enable the addon from the preferences.


It Won't Render: Stuck on the 1st 4 tiles, played with Resolution, sample size and max steps with no luck

Your screenshot indicates that you are using square samples. This means that for 500 square samples, this becomes 250,000!

This will consume quite a bit of resources, and very likely take quite some time. Unless you really want to render with that many samples, I would uncheck square samples, or change this to something more reasonable (like 45-55
). If this is your final render, perhaps 2000-3000 (not squared) may be sufficient.


How do you keep parts from showing through the skin on a transparent character?

Materials in Blender can be set to be transparent, so that light can pass through any objects using the material. Transparency is controlled using an “alpha” channel, where each pixel has an additional value, range 0-1, in addition to its RGB color values.
Transparency
So if you want an object to be transparent you could change (this can also be animated / keyed) the material and or alpha level of those objects you want to be transparent or solid.
Here's a detail link with a tutorial along with an example / walk through showing you how to do this.
Alpha / Transparency instructions
Video Link explaining Alpha / Transparency


Cycles: Export each light into separate files

You may noticed, that Cycles is lacking a certain Blender Internal functionality which would help this. Mesh lights don't have a This Layer Only option.

My suggestion would be to use a python script.

Reserve one layer each for your specific lights. Store the specific lamp objects on each layer. You mustn't have other objects in these layers, but the scene should still be intact if either of the layers was switched of.

In my example case I will place a key, fill and rim object respectively in layers 0, 1 and 2.

These settings are specified in an array at the beginning of the script.

import bpy

lightLayers = [
            [0, "key"],
            [1, "fill"],
            [2, "rim"]
            ]

layers = bpy.context.scene.layers
filePath = bpy.context.scene.render.filepath

for i in range(len(lightLayers)):
    for j in range(len(lightLayers)):
        layers[j] = 0
    layers[i] = 1
    bpy.context.scene.render.filepath = filePath + lightLayers[i][1] + "/" + lightLayers[i][1]
    bpy.ops.render.render(animation=True)
bpy.context.scene.render.filepath = filePath

My render output is set to: "//images\".

Pressing Run Script will execute the script.

Each Light Layer is switched on, the others off (none Light Layers will not be affected), then the scene is rendered.

This will produce the following.


How to lock object face a certain distance away from another object face?

Set object2 origin point to its right bottom corner and you are free to scale in object mode.

Select object2, go to edit mode, select right bottom vertex, Shift+S > Cursor to selected.
Return to object mode Shift+Ctrl+Alt+C > Origin to 3D cursor.


Aha figure it out! I had to call the operator via the search menu.
So the process is:
1. run the script,
2. move mouse to viewport,
3. press space and search for raycast.
4. chose "View3D: RayCast View Operator"
5. click on your object


Mesh modeling review: black hole, cannot select face, joining subdivisions

Your question is loaded with many questions that appear to be regarding best modeling practices.
Quads vs N-Gons
In general, there are many ways to model something with either quad or n-gons. You have to ask yourself what you would like your end result to be.

For example, if you are modeling something that you wish you use a subdivision modifier or use loop cuts, then it is best practice to use quads.
If you are modeling a low poly asset that you wish to export to a game engine, then it is also preferable to use quads (that will then get triangulated upon export).
If you are modeling something that you wish to render within Blender as is, without the need to subdivide the geometry further, then n-gons are suitable to use as well.

In your case, since the hulls of boats are usually smooth, you may need to add additional loops and/or use subdivision modifier, so it is recommended to use quads.
Normals direction
Your next question is regarding the direction of your normals. If their are pointing inwards, then they appear dark.

to enable viewing normals, open up the "N" toolbar by pressing the N key on your keyboard in edit mode, and scroll down to select "view face normals"
You can flip the normal of a face by selecting it, and searching for the flip normals command (using the space bar).

Limiting Selection to visible
Based on the file you provided, you cannot select the face at the bottom of the cockpit because you had you have not limited your selection to visible, meaning you can see the bottom faces in solid view.
To enable the option, click the "limit selection to visible" button in the 3d viewport header
Joined vs separate objects

Similarly to the consideration required for quads vs n-gons, it's best to think about what is the required end result.
If some smootheness (via subdivision modifier or additional edge loops), then it's best to have connected objects. However, they should also be quads.
It instead you are modeling disparate elements, then there is no need for the meshes to share vertices.

Best modeling practices
In general with mesh modeling, it is better to start from a single object that you can then subdivide with loop cuts and/or extrusions to get the desired result. I would suggest going through tutorials on youtube.
Below is a quick example of how to model the boat starting from a plane, with a few edge loops, extruding, adding subdivision modifier, and adding additional edge loops to control the softness/hardness of edges.


Turn on edge selection mode at the top left of the 3D viewport window. You have it on face select mode currently.


Character Rigging in Blender for Unreal Engine

I'm currently playing with this too.

To get an idea of what you want to do, take the UE4 Mannequin's skeletal mesh and export it to FBX. File should be 853KB.

Import that in blender - on the blender import settings you want 'Z up' and 'Y forward', and on the Armatures tab you want 'Automatic Bone Orientation' ticked.

Then you have a clear look at what's going on with the UE4 mannequin (which has all those premade animations) - it has a root bone in the skeleton etc. From there you can work on changing the model to whatever you want and rerigging the existing armature. Then animation retargeting should work nicely.


help needed with shading applied to a certain part of a mesh?

You can:
Select faces of your mesh in edit mode and assign them different materials. This is the easiest, most straightforward way.
Or
Use texture paint to create a black/white mask for the two textures. Combine the two shaders (Put them in the same material) using a Mix Shader, and plug in this mask as the mix factor. This allows for more control, like smooth texture blending and shapes that are not limited to the object's geometry. However, this takes more work to do.


How do I use an ambient occlusion map in the BGE?

If you don't care much for physical accuracy then you can just multiply the AO map over your albedo texture. Quick and easy.

(I like using nodes but the UI can also be used)

If you do care, though, it gets slightly more complex.

This is the formula we will follow:

Diffuse = (Direct + Indirect) * Color

Direct means material node

Indirect is what is often called Ambient term
It can be approximated as follows:

Indirect = AmbientColor * AO

If you want something a bit better to represent the AmbientColor you could make yourself a pre-convolved environment map (A.K.A. very blurred HDRI)

You might also want to have a UV channel that is used just for AO, separate from the albedo texture. If you do end up using one please, do not use the light-map unwrapping method, it will lower the performance of your game significantly.


Blender render (cycles) animation slows down midway. What causes this and do I depend on the new time per frame?

The render time on each frame depends on the content of the scene at that particular frame. So it is normal that render times vary, if the complexity changes throughout the scene.


Can a custom filter read property value and use it?

Yes you can have a game property in a GLSL shader.

Here is a good read on making exactly what you want, a blur filter with a controlled blur amount from a game property (plus blend file).

From the script linked above, you can just use the property name blur_amount in the GLSL script.

Declare the var like this, then use blur_amount however you want to.

uniform float blur_amount;


Blender 2.8 resize single edge where rest follow proportionally

i think this is what you want to achieve..

select this vertex, then shift+s cursor to selection

change the pivot point to cursor

scale down to 0.5, and it should give you this result


The new plane (1) has no UV coordinates. You have to select all faces and unwrap them. Then you should be able to paint on all.


I just grabbed Blender 2.72b source files to check this issue.

In short: with current Blender (2.72b and older) it is only possible to draw to the "combined" and "vector" passes of a multilayer OpenEXR file with Blender's paint tool.

Reason: Blender's low level paint tool C algorithms (filling, painting a stroke, etc.) are all solely working on 4 channel interleaved float buffers internally. The "combined" and "vector" passes are always stored as 4 channel layers to .exr files by Blender, so those are fine, but most other render passes are stored as 3 channel layers or even 1 channel layers to .exr files and when Blender opens those other layers from .exr files it allocates 3 channel (or 1 channel respectively) interleaved float buffers internally for them.

It also does not make any difference BTW whether you select "RGB" or "RGBA" in the render settings, you will get the same .exr file and end up with the same problem.

UPDATE: I wrote a patch against Blender 2.72b which solved this problem for me. Feel free to test it, forward it to Blender developers or whatever you think might be appropriate. Please note that this patch is neither optimized, nor thoroughly tested, so make sure you have a backup of your .exr file(s) before painting to them.


you should try to mark those edges and use the bevel modifier with the option set to bevel weight, instead of using way too many cuts like you did.
Dissolve all edges loops between the two cuts.
OR use a bevel on a sharp corner edge with a suitable amount of division, like in my drawing. Usually, 3 or 4 cuts are enough to achieve the effect you want, provided that you also have a sufficient amount of geometry (for example a subdivision modifier in the stack).

Hope it helps. Check my drawing on your example.


(In 2.8) select the 2 control points at the ends of the segment of interest, Right-Click > 'Subdivide'


Clear (or edit) your custom split normals data from the Object properties->Geometry data section.  These custom normals are causing this issue.


Make Reference Images Visible in Animation

tap Shift - A -> add image as planes

choose rendered view (right most button)

optional: in shader editor connect the texture directly to the output, so the lighting is always as the original picture/movie

result:


How to parent a grease pencil with armature?

There is a drop down menu below the layer.choose armature and then choose bone..there should be a list of bones. (it does not matter if the gp layer is attached to an object or the scene.)


Random lines popping up with Freestile when Sketchy

Play with the error settings for the bezier curve modifier:

Original:

Smaller value:


How can I make my gear simulation in the BGE work?

This problem is caused by the moment and rotation restraints on the top gear. To fix this, I recommend removing them:

Now, if you run the simulation,
The top gear is responding to the collision with the bottom gear. This is progress. (smile! - it almost works)

We just need to get the gear to ignore translation, but still respond to rotation. This can be done using a rigid body joint.

Now, we need to apply the right settings to the joint.

This joint will allow no translation, and will only allow rotation along the X axis. But this joint works relative to another object. We need to put a stationary object in the target field.
A static cube will work. (any other static object should also work as well)

Now, we simply set that cube to be the target object.

The top gear will now have it's X,Y, and Z translation locked to the cube's position, and since it is static, it will not be moving. The top gear's Y and Z rotation is also locked to the cubes rotation, and since it is a static cube, it also will not be rotating. The last step (this is optional) is to paint it your favorite color.

Now we can test the simulation:

Yay! it works!


How to use textures from texture tab with material shading

I couldn't tell if this is the way it was always meant to be, but a workaround could be to use the Texture Paint workspace. On the left panel you could create a new image and name it anything you want. In the Shader Editor, you add an Image Texture, browse to select the image you've named earlier and connect it with the Base Color of the Principled BSDF. At this point, in the Texture Paint workspace, you could paint using the earlier created Clouds brush from the Texture Properties either Image Editor or in the 3D Viewport, for perspective painting.


How to model a square (starting with one vertex)?

Or :
Presuming the first vertex is selected :

E
X
1 Extrude along X axis 1 unit

A
A Double A, to first deselect the extruded vertex, but A again to select them all

E
Y
1 Now extrude both two precedent vertices to make the square


Is there a way to tell Blender NOT to load certain images during render?

This can be achieved by enabling "Use Camera Cull" in the Simplify settings in the scene tab, though it will remove entire objects that are not in the camera's view instead of just textures and will affect reflections/shadows as a result.

An alternative solution to your problem is to enable "Persistent Images". Blender will keep these large textures in memory instead of reloading them on every frame, thus reducing your render time on subsequent frames without altering the final image (shadows/reflections) in any way.


Problem

This behavior is because Object Data > Background Images only shows the image in the viewport -- there is no physical image. An easy workaround uses compositing.

Workaround

First, go to the Render tab > Film dropdown and check Transparent. This will tell Blender to only render the cube as opposed to the cube and the gray background.

Next, switch from the Layout layout to the Compositing layout. Add an Input > Image node and use the bottom left button to select your image (it has already been added to your .blend file, so it should be there).

Add a Distort > Scale node and connect the Image node > Image output to the Scale node > Image input. Set the Scale node > dropdown to Render Size. Add a Color > Alpha Over node and connect the Scale node > Image output to the top Alpha Over node > Image input. Connect the Render Layers node > Image output to the bottom Alpha Over node > Image input. Connect the Alpha Over node > Image output to the Composite node > Image input. Your nodes should now look like this:

Render.


Blender's object oriented approach uses a generic object for items in a scene with a varied data block that varies for each type of object. Using python we can create the lamp data and use it when adding an object to the scene, which can then be positioned where you want it. You could add a sun lamp and rotate it as desired, or if you wanted a spot light you could use a trackto constraint to point it at the object.

import bpy
from math import radians

# sun lamp
light_data = bpy.data.lamps.new('sun', 'SUN')
light_obj = bpy.data.objects.new('sun', light_data)
bpy.context.scene.objects.link(light_obj)

light_obj.location = (2.0,2.0,2.0)
light_obj.rotation_euler = (radians(10), radians(15), radians(20))

# spotlight
light_data = bpy.data.lamps.new('light', 'SPOT')
light_obj = bpy.data.objects.new('light', light_data)
bpy.context.scene.objects.link(light_obj)

light_obj.location = (2.0,2.0,2.0)
light_constr = light_obj.constraints.new('TRACK_TO')

light_constr.target = bpy.data.objects['Cube']
light_constr.track_axis = 'TRACK_NEGATIVE_Z'
light_constr.up_axis = 'UP_X'

light_data.spot_size = radians(25)


Those are Shadow Terminator artifacts. The most common way to deal with them is adding more geometry, usually with a subdivision surface modifier.

But starting with blender 2.9 you can control the Shadow terminator aritfacts directly in the Object Properties. In the Shading section use the slider for Shadow Terminator Offset:


How to update an object after changing its uv coordinates?

This is a simple fix - all you need to do is run the update() function on the object's mesh data: obj.data.update()

Depending on your intended use case, you may also need to run bpy.context.view_layer.depsgraph.update() to update the dependency graph.


How can I simulate physics steps in advance?

I think you can use four ray sensors, info can be found here from blender api.
Depending on what you are doing, you may want use radar.

From that if some sensor collides with some obj you can get the distance obj1.getDistanceTo(obj2), world trajectory and speedobj2.localLinearVelocity in m/s.

Anyway, I come up with this, the trajectory. I hope its useful.

from bge import logic
from mathutils import Vector
import math

class vehicle:

    def __init__(self, body):
        self.cont = logic.getCurrentController().owner
        self.body = body
        self.front_ray = self.cont.sensors["front_ray"]
        self.main = self.moving
        pass

    def moving(self):
        velocity = Vector((0,40,0))
        velocity.magnitude = 4
        self.body.setLinearVelocity(velocity,1)
        self.body.applyRotation((0,0,0.02),1)
        if self.front_ray.hitObject:
            self.check_thread(self.front_ray.hitObject)
            pass
        pass

    def check_thread(self, obj):
        rot_obj = obj.localOrientation.to_euler()
        self_rot = self.body.localOrientation.to_euler()
        max_angle_limit = math.radians(-160)
        min_angle_limit = math.radians(-200)

        if rot_obj.z < max_angle_limit and rot_obj.z > min_angle_limit:
            print("ALARM : COLLISION DETECTION FROM :", self.front_ray)

        pass

def main(cont):
    own = cont.owner

    if not "init" in own:
        own['init'] = True
        own['vehicle'] = vehicle(own)

    own['vehicle'].main()


How can I get a straight UV map when I unwrap?

A simple way to do this, if you don't want to unwrap again, is to select and scale the edges. Select the top edge of your curve like this:

Then press:

S
Y
0

The scaling result: (Repeat for the bottom edge)

Lastly scale the bottom edge along the X axis. The final result:


How to change the camera used for render?

This is because you have an image strip in the Video Sequence Editor, so pressing F12 renders from the strip rather than from the scene.

Remove the image strip or disable Sequencer in Properties > Render settings > Post Processing to render from the scene.


Can I rotate objects the with 3 orbits around it like in Unity or SketchUp?

If you press R the object will rotate on the view axis. If you press R then X, the object will rotate on the X axis only. If you press R twice it will rotate on both axis except the view one. If you press R and then Shift + X it will rotate in both axis except X.

If you set the curve in the selector on the header of the 3D view you will have your "Rotators" around the object.


Array modifier with some kind of scaling transform for each iteration

You could put the array under the control of another object (here, an empty,) by checking 'Object Offset' Then any object-level transform on the empty will be applied to each instance in the array.

In this example, X runs across the steps, and Z is up. The empty has been scaled in X.

This gives a step-wise taper. The progression is geometric, not arithmetic, though.

If you wanted a linear progression, you could make each step out of two halves: assign a 'Mirror' modifier after the array,  checking 'Clip' and 'Merge', In this case, instead of scaling the empty, translate it  a little in X. This would have the effect of translating the two halves toward one another by a constant amount, each step.

If you want the taper to be continuous, don't do as above. Instead, leave the array as it was and assign another modifier: 'Simple Deform' > Taper. Select the appropriate axis for the taper.

By default, the taper acts on both axes orthogonal to the taper direction. Lock off any axis you want to remain unaffected.. in this example, Z.

(The empty in the second illustration is redundant; I've used the step's own axes.)


3) You might get along with curves and bevel. Not sure if you can get nice corners as in the video though.


Particle System, want to emit a particle AND a lamp

After a short experiment I have been able to get a lamp to appear as part of a particle by using the Group option in the Render section and activate the Whole Group checkbox.  Since the mesh and lamp are both part of the group I created they are both instantiated for every particle.

Probably the biggest gotcha is to set the Size property underneath the Whole Group checkbox to something reasonable (it defaults to rather tiny).


When I open blender, my textures and materials turn bright pink?

This means that Blender can't find your textures. So you either moved or deleted these textures. Simply relocate your textures for your material and it will look like normal. You can pack all of the external data (images, sound files, video files and appended data) into your blend file but this will heavily increase the size of it, to do this: File> External Data> Pack all.


You can do this with an array modifier and a curve modifier (see this post):

Add a slightly extruded circle/cylinder with no caps:

Add an array modifier:

Add a curve modifier:

For the array to deform as expected the object origins must be in the same place.
Add two half spheres as start and end caps:

the length can be animated with the Count value of the array modifier.


Importing obj files from a list variable python

Thats an "accident" of early 1980’s. The first version of MS DOS used the forward slash for command-line options. When Microsoft added support for folders in MS-DOS 2.0, the forward slash was already taken so they used a backslash instead. Still stuck with this incompatibility 39 years later.

Windows: C:\folder\file.txt

Most other OS: /folder/file.txt

But \ is an escape character in most OS, thats why you have to escape it and to escape it you use another \ so it becomes \\.

Using the variable os.path.sep will give you the correct one, so you can simply use it to build your paths. But if you know which os you are working on you can write it by hand, your choice.


How Can I create this Slime dripping down effect?

Here's a node group.  Either of these Math -> Divide nodes should give you something to start from.  There are places where this produces some weird lines due to the subtract operations, just move the Location on the Mapping node around until you get something workable.


Can I refer to another object's properties from a Cycles node shader? Drivers? If so, how?

As you have said you can use drivers  were you get X,Y and Z separately from using drivers then combine them and use the result :

here is one of the drivers :

and this is the what changed in the node setup :

and this is the result : I'm moving the Empty object 'which is not visible'

Note : i didn't use driver directly on the 'combine XYZ' because it was clipping negative values


How to create a horizontal strip inside a circlular plane?

It really depends on your final goal but you could do it with the help of the knife tool (K then C to cut orthogonally). Also, use a Mirror modifier to make it simpler:


No, you have to change slots every time you render (shortcut keys 1 to 9 on the upper keyboard numbers).


The reason it doesn't cut clean is because this kind of curved tube has self-reverting faces in the corners :

You can fix it by using the knife, adding vertices and merging the closest vertices in those areas until you get this kind of result :

Then you should be able to select the self-intersected part of the tube with Ctrl+L :

I don't think there's any automated way to do this.


How to integrate Zbrush with Blender for long run animation projects?

Here is a plugin for blender that allows for a very good degree of integration between z-brush and blender.


How to activate a node only on certain frames?

Just found this:
One needs to use the Right click/keyframe property on a node and set a serie of keyframes, to activate, deactivate, modulate the property.


Is it possible to determine the UI panel class that is parent/host to an operator when its button is clicked?

You can define a property for the operator in order to identify something.
For instance:
class SimpleOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"

    # >>>> Declare a property
    some_value = IntProperty(default=0)

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

    def execute(self, context):
        print(self.some_value)
        return {'FINISHED'}

Then, in the panel you can assign the property value as you want:
class HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_idname = "OBJECT_PT_hello"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    def draw(self, context):
        layout = self.layout

        row = layout.row()
        op = row.operator("object.simple_operator")
        # >>>> Assign its value
        op.some_value = 1
        op = row.operator("object.simple_operator")
        # >>>> Assign its value
        op.some_value = 2

Alternatively, you can assign the value in a subclass if your want to work with subclasses.


Wireframe shading issue in Blender 2.91 viewer

Go to the viewport shading options while in wireframe and check x-ray. You probably have it disabled.


First start with sverchok. looking for feedback and how can i make this more efficient

Let me just insert the gist
https://gist.github.com/b846e86e59d5458d0b87abba5205f6b2
This example of some ways to solve issue. I don't know aim of your node tree.
First of all, you can use not only extrude to extrude. loft, copy with uvconnect, matrix tubes, simple pipe node or whatever you need. There are tonns of solutions depend of what you want.
Import json and test.


What's the "deselect all" hotkey in Blender 2.8x?

The old behaviour is still available in Blender 2.82. Go to the Keymap section of Preferences, and in the first panel (titled ‘Preferences’) tick the ‘Select All Toggles’ option.


It looks like you tried to extrude the doors inwards. This leaves the edges in between the two doors, and there are now duplicate faces there. There also appears to be duplicate faces at the bottom of the doors.

Try going to vertex select mode and use box select (B) in wireframe mode to select all of the verticies in the area. Then you can delete them.


Animation nodes - Vertex colors to transforms?

You can retrieve the color using the following code:

object.data.vertex_colors[layerName].data[0].color

Where object is your object and layerName is your vertex color name.


Does Blender have a software-limited amount of RAM it can use?

What is memory management (from http://www.tutorialspoint.com/):

  Memory management is the functionality of an operating system which handles or manages primary memory. Memory management keeps track of each and every memory location either it is allocated to some process or it is free. It checks how much memory is to be allocated to processes. It decides which process will get memory at what time. It tracks whenever some memory gets freed or unallocated and correspondingly it updates the status.

There is no software cap. There can't be - it would have to be coded in for it to be. Blender will use all your RAM up to 16TB (64bit). Its up to the OS to provide the memory for blender.

If you have a page file it starts at around 2 GB or 4 GB and windows expands the page file when needed. However, they might not be as fast as Blender requests more memory. If this happens, Windows does not allow Blender to get more RAM and causes an out of memory exception which crashes Blender.

At that point the page file gets bigger and in second run of Blender its very likely everything will run/render without problems.

If your OS fails to allocate some memory for Blender fast enough, Blender will crash.


How do I create a circular slide (similar to a water park slide)?

Creating a slide is a rather simple process. You can easily create a slide using two modifiers. Here is how its done.

1. Create a curve to use as your path:

add a bezier curve and modifiy it

2. Create a cross-sectional of the slide:

Use a polygon mesh instead of a curve object:

curves when convertedto polygons are messy and you will need to do some manual clean up
you have easy control over the polygon count

Make sure the cross-sectional has some depth to it, it should be a 3d mesh not a 2d outline or plane.

3. Add Array and Curve modifeirs:

Select the cross sectional mesh and add an Array and Curve modifier
Array modifier settings:

Fit Type: Fit Curve, this will fill the path out for us automatically
Merge: True, erases inside polygons

Curve modifier settings:

Object: select the curve

4. Fix the slide:

Based the curve the slide can oriented in the wrong way.

Select the curve and go into edit mode.
Select the points of the curve that are messed up.
Adjust the tilt using Ctrl+T


How to get glare on "Quick Smoke" (Fire & Smoke explosion)

You can check this video, as well as increasing the emission strength of the fire material

https://youtu.be/ctd_09qHacA?t=35m3s


How to make an object's texture conjoin when exported to Photoshop?

To physically merge the cubes into one solid mesh:

Join the cubes into on object by selecting them all and pressing CtrlJ
Switch into edit mode (Tab), and remove doubles (A to select all and then W> Remove doubles)
You may need to remove internal faces too. Select internal faces by pressing Internal faces in 3D view > Header > Select, then delete them with Delete> Faces.


Is there a way to see more physics setting for an object?


Blender bones are confusing. How do they work?

When you are in Pose mode the rotation centre is the head of the bone:

What you show is the upper leg bone parented to the lower spine bone. You're talking about constraints but it's not cleat what you're talking about, in Blender, Constraints are tools used to control objects or bones, like for example Inverse Kinematics constraint, but I don't think there's any constraint between your upper leg and lower spine. I think you mean that these 2 bones are parented, upper leg is the child of lower spine. In that case there's a doted line between the two. This line appears between the parent's tail and the child's head. It won't cause any problem of rotation or please be more specific.

There are 2 kinds of parentage. The first case is the previous one: When you parent a bone to another one but you want the child to stay away you need to choose in Keep Offset mode: select the bone you want to make child, then the parent, then ctrlP > Keep Offset. If you want the child to stick to its parent, choose the Connected bone. If you extrude a bone from another one, it will be a connected child by default. You can separate it definitely with altP > Clear Parent, or keep it the child with altP > Disconnect Bone.

You'll find a lot of tutorials about bones and rigging, explaining everything here would be a bit tedious, I think BlenderStackExchange is more for punctual problems.


My baked normals only appear in material view but not rendered view?

I fixed it, not sure what was going wrong but i loaded to an earlier saved file and it works just fine. Not super happy with how it turned out...but such is life!


Navigation locked out during operations?

I don't think you can, select what you want to extrude then dezoom as needed before hitting E .


Armature not following path for animation

Press on the constraint Animated Path button, otherwise the object won’t move
Put the Offset at 0 if you want it to begin at the beginning of the curve
Press AltG to put it at the beginning of the curve, the new world center of the object is the beginning of the curve now that it is constrained to it, so reset location will bring it to this point
Choose Forward Axis > X as it is the front direction of the armature

It should work


Possible causes for a Blank render:

No lights in scene.

Objects disabled for Render in outliner (camera icon).

Strips in VSE and Sequencer enabled.

Objects in different layer, or in a layer disabled in Render Layers.

Object blocked by other objects.

Active camera aiming in a different direction.

An object in the scene set as active camera.

Any, some or all of the above.


It's rather simple as to do this, also, for free :)

Thanks to @3DSinghVFX for the answer in a comment.

  During audio rendering, first select audio container (e.g. mp3) then select the "split channel" option which will generate six tracks for 5:1 setup. Then you can mix these tracks with the help of some Ambisonics plugin to generate ACN/SN3D format.

Add all the tracks into a DAW (I'm using Reaper), and enable the WigAmbiRemap JS Effect. Set the Outgoing Amb Normalisation to SN3D and Outgoing Channel Ordering to ACN. Then render to a file with 4 channels.

Then, render the video and "glue" them together with ffmpeg.

Use this in the terminal (CMD or Bash will do, ffmpeg must be installed)

ffmpeg -loop 1 -i video.mov -i ambiX.wav -map 1:a -map 0:v -c:a copy -channel_layout 4.0 -c:v libx264 -b:v 40000k -bufsize 40000k -shortest output.mov

You can change the following:

video.mov can be a .mov file or image file, and represents the video.
ambiX.wav is the 4-channel B360 Ambisonic file.
output.mov is the output file.

After that, pop it through the metadata injector (Making sure you check the 1st and 3rd checkbox, 2nd is optional) and you're done! Just upload it to your site of choice.

Source: YouTube, Ambisonics, and VR


How to make a realistic snow material in Cycles?

Here is what I have come up with:

In a still shot the sparkles look kind of like fireflies, but when you animate the camera they look great!

Here is the node setup:

The base material is the diffuse and glossy mix.  It uses a fresnel the opposite as you would normally, grazing angles give more diffuse.  I have found that this looks quite good.  There is also a slight bit of bump applied to the diffuse which greatly enhances the look.  You can adjust the roughness on the glossy shader to change how icy the snow looks, smaller roughness = more icy.  Values between .025 and .1 work well, I am using .1 for a fresh snow look.

The second layer is technically not photorealistic since I am adding as opposed to mixing in a gloss, but it looks pretty good.  It consists of a glossy shader mixed with no shader (this is so we are adding a fraction of a shader) and then added to the base shader.  The glossy has a very small voroni texture plugged into the normal to get the sparkles.

Here is a close up, for this I used an even smaller voroni, size = 30,000:

The purplish/yellowish is from the HDR, I am using Greg Zaal's Golden Gate.

The mesh is just a large bent plane with six subsurf levels and two displacement modifiers using different sized clouds textures.

The separate/combine RGB nodes just filter out the green channel of the voroni so it looks like a normal map :).  It's totally unnecessary but you could use it to change the strength if you want.


How can I change Blender's Zoom View to include the Alt key?

If you want to zoom using Alt and holding middle mouse button:

Press CtrlAltU to open User Preferences
Go to Input and find "Zoom"
In the 3D View section, find "Zoom View" and change Ctrl Middle Mouse to Alt Middle Mouse

If you also want to zoom by holding Alt while scrolling the wheel:

Find "Zoom View" item with "Wheel In" / "Out" and add Alt to the shortcut
Disable "Frame Offset" shortcut

Personally, I prefer to getting used to Blender's defaults if possible, as it often fit's the different workflow better.


I'm fairly new to Blender and may not be much help; I'd leave a comment, but don't have that privilege yet :/ You'd think giving comment approval before answers... oh well.

Anyway, I think the cup would have to be attached to the cage, like in the real world.  The pins of the cage mesh would have to be inserted in the cup with holes in the cup axis to keep the cup from falling, not joined, like the real thing.

I would put the holes in the side of the cup with a reinforced thickness so it would have enough geometry that it would lay on top of the wire, and the wire wouldn't pass through this.  I've had to do that with objects standing on a plane, when the plane had no thickness even though it was a rigid body.  I wouldn't parent the cup to the frame either, the frame and the cup would have to affect each other, and parenting might/would prevent this.

This would allow the cup to 'hang' in the wire mesh with physics.  The other consideration would be based on the geometry of the cup, with a weighted cup, such that gravity would allow it to spin around the wire axles and hold the cup in the required position only stopped by the tab against the wire; in other words, bottom heavy.  That way, as in the real world, when it rotated to the top, the cup would stay properly oriented and it would contain the ball, and the tab would stop it, again, like the real thing.  I think you can also play with the center of gravity, if the cup is not perfectly shaped to hang like you want.  I think the cup would have to be a rigid body, as I'm sure the wire frame would be a rigid body, that way the cup would hang on the wire frame and not pass through it. You might also have to mess around with the material of the ball, so that it wouldn't have the same weight as a solid ball. My experience is they're more like ping pong balls, or small enough not to change the overall behavior of the cup.


Workspace - Filter Add-ons Question (2.80 and 2.81)

As a quick workaround, you could change the "category" in the bl_info section to one of the supported ones. Though "Import-Export" is listed as supported for filtering, it currently is not.

You should be able to filter them after changing, good for maintain addons via workspace.


Strange artefacts after applying a subsurface modifier?

Same settings as you, and no Z-index fight:

Can you share the blend file?
thanks


Use the Bridge tool from the Loop Tools addon to connect the loops, then slide them into each other and remove doubles. You can also cut a new loop between them to get the exact midpoint.


How to keep Blender from adding frame numbers to output filename?

Simply put test.mp4 as the ouput not just test without the file extension.


Cooky cutter from svg file for 3D printing

Solidify Modifier

Image above. The blue flower shape has the solidify modifier.  You can press apply to make it permanent.  You may need to look closely to see the thickness on top, and clicking on the image will show a larger image.

You can scale a ring smaller.  You can also scale the extrusion as a modelling technique.

Loop Cut and Slide
In the image below extra rings of vertices were added along the edge.


How to add a face outside a round feature

Just adding an answer so it can be marked as solved :).

You can use Bridge Edge Loops for that.
While in Edit Mode select both Loops and go Edge > Bridge Edge Loops
Note that it will create triangles. To make quads, you also need to subdivide the rectangle.


Text to mesh > remesh not giving smooth enough results

Use only bevel with very low amount, for example 0.003. Limit Method is set to Angle. For more precision use limit method "Weight", select edges and change weight for the selected. The weights are in properties shelf / Item / transform /edges data / mean bevel weight. To see it you have to be in editmode.


Texture rendering looks different from preview

I almost give it up :)

You have set body material in View Layer Properties > Override - you have to disable it.

Second thing is your UVMap - rotated 90 deg. = squized image.
If you would like to fix it, it would be such painful unwrap each feather so I would suggest just to rotate original images to landscape orintation.

Third thing is - "someone" wanted paint feather to brown and destroyed alpha channels. I saw some separated alphas (masks) packed in your file, so you would probably use them instead original ones.
Funny, with all these errors, it is looking cool in Worbench engine :)

Note to Normals direction - if you will have some shading issue in render,
select all faces and press Shift+N.

Nice flight, your forensic team from future, in hope message will be delivered on time :)


You can use the Home button or press A to select all of your nodes and then use Numpad . to frame selected.


Does the Principled shader alleviate the need for custom PBR setups?

Yes - and no.

For most 'real world' materials, the Principled shader should be able to produce very good results. However, it is not perfect and cannot deal with every situation - otherwise it would have far more parameters, inputs and sliders than would be practical.

The existing principled shader should be fine for pretty much all 'simple' materials - those where the visible effect is due to the material and surface properties alone - or where there is a single layer of 'clearcoat' that is within the capabilities of the 'clearcoat' parameters.

This should be sufficient for, say, 99 percent of materials (or more!). However, there are feasible situations where the principled shader is insufficient - and under those situations you would again need to combine multiple shaders. For example, a surface with multiple 'clearcoat' layers  with different properties of each layer, or a surface where the micro-detail has a significant effect on the appearance (such as the fine structure of butterfly wing scales or the irridescence of beetle wingcases).


Where's "Copy from Active" in Blender 2.8

You can find something similar by pressing F3 and typing : "copy rigid body settings".


The code for the addon can be found here:
https://github.com/jayanam/jmesh-tools

The last commit is version 1.0.1.4 to which I added the extrude with the mouse cursor for primitives.

The logic is like this:

The primitive mode is a modal operator (fc_primitive_mode_op.py) in which a shape that is painted to the surface can be extruded when the "E" key is pressed. Then the 2d start pos (current mouse pos) is stored in the types/shape.py class as member self._extrude_pos
Now when the mouse is moved the method handle_mouse_move of the shape.py is called, the mouse 2d position is passed as parameter.

I want to use the extrude start 2d pos and current mouse 2d pos difference to set the extrusion length for the vertices. All the logic for this is in the types/shape.py class. The goal is to implement an extrude functionality just like the one in Blender for meshes. Thx for your help.

def extrude_vertices(self, context):

    dir = self._extrusion * self.get_dir()

    for index, vertex3d in enumerate(self._vertices):
        if not self._is_extruded:
            self._vertices_extruded.append(vertex3d + dir)
        else:
            self._vertices_extruded[index] = vertex3d + dir

    self._is_extruded = True

def handle_mouse_move(self, mouse_pos_2d, mouse_pos_3d, event, context):

    if mouse_pos_2d and self.is_extruding():
        dir = self.get_dir()
        mouse_3d = region_2d_to_location_3d(self._view_context.region, self._view_context, mouse_pos_2d, dir)
        ext_3d = region_2d_to_location_3d(self._view_context.region, self._view_context, self._extrude_pos, dir)

        diff_vec = (ext_3d - mouse_3d)

        dot_prod = diff_vec.dot(dir.orthogonal())

        self._extrusion = dot_prod

        self.extrude_vertices(context)
        return True


How do I adjust the sensitivity of zooming and panning?

I hate these useless moderators.  The scroll sensitivity is a windows issue, not necessarily blender.  Google answered my question at the tip top of my search:
Change Mouse Scroll Speed in Windows 10
Open the Settings app.
Go to Devices -> Mouse.
On the right, select Multiple lines at a time under Roll the mouse wheel to scroll.
Adjust the slider position to specify the number of lines between 1 to 100 lines at a time.


Where is the "See Through" selecting button in 2.81?

It's still there.
Right next to viewport shading options.

Now it's called X-Ray.
Works in Edit and Object mode.


You mention bevel per vertex but then you proceed to illustrate beveling per edge.
Not sure what you really want to achieve, sounds like what Bevel Weights are for.
Add a Bevel Modifier to your mesh object, for ease of mental calculations set its Bevel width to $1.0$, then proceed to turn off Clamping and set the Limit Method to Weight.
Then in Edit Mode on your mesh, select desired edges and press Ctrl+E Edges > Edge Bevel Weight to control the bevel width on a per-edge basis.
Edge weight acts a multiplication factor over the bevel distance, if you set bevel distance to a round number like $1.0$ it will facilitate adjustment. If now want a bevel of $0.5$ units just set the weight to $0.5$, if you want a bevel of $1$, $2$ or $3.7$ just set the weight to $1.0$, $2.0$ or $3.7$ respectively.


Ok.
First step: delete the map (make a backup copy of the .blend file first).

Then you should try the several unwrapping options. If you don't find one that make a good map, you could try unwrapping the mesh in more steps (some faces per time). For example you could map the two symmetric halves separately.


Blender RGB masking with segmentation. How to? If possible

You can try with this solution: Create a segmentation picture with each object class rendered in different color ?.
It worked for me.

Moreover, if you want sharp edges you can set render properties -> film -> filter size for eevee to 0.00.


You could take the dot-product of the normal of the surface with the unit Z vector, as a measure of the angle with Z.
It's cos(the angle with Z), if you want to arccos it, for the actual angle, in radians.


How do blender units and meters, feet, or yards correlate?

Blender units
The Blender units system is a decimal unit system that can be whatever you want it to be. By default, it's implicitly considered meters. If you go to the scene tab in the properties panel, then to the gravity section, you can see that the rate of acceleration due to gravity is (0.000, 0.000, -9.810). 9.810 is the rate of acceleration in meters per second squared. So as you can see, it's implicitly considered meters. Now, if you change this value to -.0981 and every rigidbody's mass to 1⁄100 of what it was, you would now be working in centimeters and grams (or the cgs system).
Metric units
First off, let me start by defining a list of metric measurements that Blender uses.
Length

(km) kilometer [1000 meters]
(m) meter
(cm) centimeter [1⁄100 meter]
(mm) millimeters [1⁄1000 meter]
(µm) micrometers [1⁄100000000 meter]

Mass

(ton) metric ton [1000 kilograms]
(kg) kilogram
(g) gram [1⁄1000 kilogram]

If you go to the units section in the scene tab, you can see that there are three different options ("None, Metric, Imperial"). "None" is Blender units. If you select metric units, Blender will explicitly use metric units. Check back in the physics panel, and you'll now see (0m/s2, 0m/s2, -9.81m/s2).
For another example, select a mesh and hit n in the scene view to bring up the properties panel, go to the transform section and then dimensions. If you change one of the x, y, or z dimensions to a large number, you will see that it now uses the kilometers instead of meters. And if you change it to a ridiculously small number, like .000002, it will use micrometers.
Imperial units
Imperial units are the worst to work with. Also known as the British units. This is what backward America uses. Let me again define the units that Blender utilizes.
Length

(mi) mile [5280 feet]
(ft) foot [also symbolized with a single quote: ']
(in) inch [1⁄12 foot] [also symbolized with double quote: "]
thou or mil [1⁄12000 foot]

Mass (technically weight)

ton [2000 pounds]
(lb) pound
(oz) ounce [1⁄16 pound]

Separate units
If you are using metric or imperial units, you can use the 'separate units' checkbox which makes Blender separate out a unit of measurement into two separate units of measurement of the same system.
For example, without 'separate units' toggled, a field might display something like 2.538m. But with 'separate units' toggled, it would display 2m 53.8cm
Scripting
One thing you should note is that when working with scripts, and you use a function like bpy.ops.mesh.primitive_cube_add(location=(1.0, 1.5, 2.0)), which creates and positions a cube, the values are in Blender units even if you are working in metric or imperial. So this function, when using the imperial system, would place a cube at (3.281', 4.921', 6.562') or  (3' 3.37", 4' 11.1", 6' 6.74") with separate units.


Sverchok. Duplicating an object along a path

I propose a more immediate way to do this, using the polyline Node and converting the Path to its 3 subparts using "Separate Loose Parts" Node. and picking the Profile curve as the Bevel object. A lot less complicated and uses Blender for the heavy lifting.

Note the heavy zfighting in the part where the "extrusions" overlap.


Duh, was defining the array in the for-loop


Yafaray Export Button doesn't show in Blender Render Menu

You'll need to change render engines. I'm not sure that the Yafaray plugin exports the XML (I don't have Blender open now so I can't check). The same dropdown you use to change the render engine from Blender Internal to Cycles is the one you use to change to Yafaray. However, you'll need to enable the Yafaray plugin (Preferences, Addons).


What is the invisible unselectable entity on a supposedly empty layer?

Select the suspicious layer. In the Outliner, set the Display Mode to Visible Layers:

If there's anything there – hidden or not – you'll see it there.

If nothing appears, please upload your .blend file for further diagnosis.


Copy Rotation adding rotation to start position?

There needs to be a bone for every segment like this:

The bones are connected into single chain and using inherit rotation (but this is irrelevant because it is overwritten with constraints)

In edit mode the bones were aligned with Ctrl+N > Cursor with cursor being in the center of mass of the bone chain.

Then the red mesh (the reference hair strand) has a vertex group for each vertex on the bone chain containing that single vertex:

Vertex0 is at the root.

Here is setup of every single bone exept the root bone. The root has copy location from Vertex0 as a first extra constraint in the stack:

The bones will not rotate until you simulate the red mesh now. They won't follow the mesh perfectly (that's because vertex normals and how they work) but they will follow closely. To make the chain follow perfectly the bones would have to target polygons instead of vertices (it's not supported, they can target only vertices - with vertex groups).

Here is a blend with the beginning of hair rigged:


How can you color smoke based on the smoke's temperature?

Blender Internal

As GiantCowFilms said, this isn't currently possible in Cycles (but probably will be in the hopefully-not-too-distant-future). In the meantime, it is possible with BI:

Setup your simulation. See How to simulate a gas? and the wiki for more detailed info.
Add a new material to the smoke domain, set the type to volume, and set the density to 0 (if you haven't already):

Note that this step is not needed if you used quick smoke to create your domain
Add a new texture, set the type to Voxel data, and select your domain object:

At the bottom of the texture settings, in the Influence panel, enable Density so that the texture influences the density of the texture:

Add another new texture, again with the type set to Voxel data and your domain object selected.  But this time set the source to Heat (there are also some fun options like Velocity). This will give you a black and white map of the temperature variations inside your smoke domain.

To colorize it, enable Ramp and set the color ramp to the colors of your liking. In my screenshot I moved the ends in a bit, as extreme temperatures like those at the ends of the ramp were not being reached in my simulation. (as an alternative to altering the color ramp, you could also increase the Contrast by adjusting the value slider below the ramp):

To make the color influence the color of the smoke, enable Reflection color and Transmission color in the influence panel:

Make sure the coordinates of both textures are set to Generated in Texture > Mapping. It should be by default, however I've noticed it behaving strangely recently (i.e. while writing this answer :P)

Result

(click on the image for a nicer version)

For some reason there is some flickering in the heat channel. I've noticed this with velocity before as well. (bug?)

Cycles

While it's not possible currently (as mentioned before), it is possible to create a similar effect to the video you linked in your question. By using the color blending features that were added since that video was made:

Set the color on the emitter objects:

This color can then be accessed via the attribute node:


Trouble importing a directx file into blender

Quite simply, the bmesh module is not available in 2.60

The issue of the error is the missing bmesh module.  Link to 2.60 API confirms that it didn't exist back then

https://docs.blender.org/api/2.60/#standalone-modules

it begins to appear circa 2.63

https://docs.blender.org/api/2.63/#standalone-modules

Look to see the version number recommended for the addon.

This one requires at least 2.63

https://github.com/limemidolin/directX_blender/blob/master/io_directx_bel/init.py#L7

And >= 2.66 for

https://github.com/poikilos/io_import_x/blob/master/init.py#L9


There is a bunch of definitions for Instance. The article you mention use the definition: Make it duplicate when in rendering pipeline
Instead of Alt+D, instancing will not likely directly been manipulated by user. E.g. you won't Alt+D for 1000 trees in a mountain, you will rather use particle system to plant instances for you, with some weight control or random method.
But if you want to place three identical boxes in specified places, you will want to Alt+D for actually manipulate the position for boxes.
They are similar concept but with different strategy. Depends on how you want to use them.
Other Instances
Instance is a common computer terminology that indicate we make something actually exist in memory and scene or workspace.
In Unity, instantiating an object mean to make a copy from its resources. Which might be totally as same as Alt+D in Blender. In Python or other OOP, all objects you manipulate are an instance from their class. Also, instance might mean to separate some minimum attribute to make it more easily to manipulate without having a full copy.


How to automatically switch to camera view after entering preview mode

WARNING: If you are a 100% python person, and hate my answer already, leave now, because, yes, we are using logic bricks.

You will need a "Scene" logic brick, on the "set camera" mode. Specify the camera and rig this to an "Always" sensor.

This works in a pinch, but it gives some extremely strange perspective depths, and I wouldn't recommend using it for this reason. The real way is to hit Num0 every time. Exhausting, I know.

Note: after further testing, it would appear that the weirdo bug is gone! :D I could be incorrect, but this would make this a valid method in releases 2.77-later at least. Happy blending.


How do you jump through animation keyframes in a loop?

I'd also like an answer for the same problem.
My workaround is to press Shift+Left/Right arrow to go to the start/end.
Also setting the automatic play range Ctrl+Alt+P helps. When I press the above hotkeys, it goes to first/last keyframe.


If you want to work entirely on the X-Z plane, like here (note the little axes on the bottom left):

then, every time you extrude, make sure to do E, then ShiftY: this will exclude the Y axis from the extrusion. This works even if you are not in front view.

To fix a mesh that was mistakenly extruded along the Y axis, do A(A)SY0

A: select all (twice if something was already selected)
S: scale ...
  Y: ... along the Y axis ...
    0 ("zero"): ... until its width is 0% of the original


When one handle is longer than the other, you will get a speed discontinuity at that control vertex (the curve's derivative will be discontinuous in that point). That's how Bezier splines work. There's no way around it other than using different spline type.

The way to solve this is to use a tile-able rope mesh piece, like this:

Put an Array modifier on it to tile it to the curve length and a Curve modifier to fit it to the curve:

And you are done, even when the curve has discontinuity, the mesh does not. Don't forget to provide enough subdivisions on the curve (64) and on the mesh:


Need advice to cleanup and rectify shading issues caused by boolean

I can only reccomend the tutorials from Josh Gambrell. All of his youtube channel is basically about booleans and how to clean them up.
https://www.youtube.com/c/JoshGambrell


How to center a non-symmetrical object on the X axis xith a python script?

you have to find the extreme values on x axis and calculate where should be the center :

import bpy

obj = bpy.context.object
max = -9999
min = 9999
for i in obj.data.vertices :
    if i.co[0] > max :
        max_ind = i.index
        max  = i.co[0]
    if i.co[0] < min :
        min_ind = i.index
        min  = i.co[0]

shift = (max-min)/2 - max
obj.location[0] +=shift


How to remove black color and use as transparent

You don't necessarily use the Mix Shader with the alpha channel of the image. You can also use the color channel. So on the darker areas the first shader (Transparent) will dominate and on the lighter parts the second shader (Diffuse) will get a higher value. You can plug a ColorRamp before the Fac shocket to finetune the silhouette. Of course you can use images with white background, just swap the transparent and diffuse shaders.


Animating facial expressions when using a Normal map

You can first create multiple normal maps with wrinkles at different locations(for example one map each for the eyes/mouth/etc.) and then you can simply blend them over one another using using an  mix rgb node. Then you can add a driver to the mix factor and let for example the eye bone rotation drive the wrinkle strength.


Can I save a partially rendered image and continue rendering it later?

As far as I know, there is no way of pausing or stopping a render to resume later.
You can pause the cycles rendering in the realtime viewport, but not the final render.

The most you can do is 'pause' the whole application at OS level. But it doesn't solve the 're-render later' problem, and if it crashes anyway, same situation.
You might find this post useful too.

Firstly, I'd suggest using a render farm. Pixel Plow look to be the cheapest at the moment. You can use the cost calculator but it's looking like it would cost around $2 to render what you've got.

Another solution is to render it out in smaller parts using render region.
Go to output properties and tick 'render region'

Then switch to camera view, and you can drag the corners/edges to set the region to render.

What you could do is to render out regions and stitch together later.
So you could render maybe full height strips, say 8 or so, overlapping a bit to be safe. Then at least if you crash you'll only lose 2.5 hours.

But, for time it takes to do all that faffing, wait for it to render, stitch it all together in photoshop later etc. you might be better off spending a couple of dollars on render farm.


Bevel modifier, when applied to the whole of complex meshes in particular,  can mess things up. To avoid this model the shape from a subdivided, 8×8, plane removing undesired vertices/edges. Bevel it, selected vertices only (it's called a vertex group), to obtain rounded corners as shown below. Extrude it when done and remove doubles.
Use knife project with the cut through enabled for the rounded holes as the rectangular hole is the subdivided faces deleted.


Can't Parent one bone to another - this option is inactive

If you want a bone to have a parent bone you have to do the parenting while in 'Edit Mode'. At the minute you are in 'Object Mode'. From the header of the 3D view, with the armature selected, choose 'Edit Mode':

(The bone you want to be the parent will also have to be in the same armature for it to be available as the parent).


As @Carlo suggest, the straight line is not a shadows, but the texture instead.

By changing size in the Mapping Node, you are distorting the image and the UV Map doesn't match as expected.

If you toggle muteM Mapping Node, your texture is correct.

In the Blender Guru Example, the Mapping Node is applied to the Noise Texture to achieve a "scratchy" effect.


How to make an object only collides with the terrain?

It's simple: use collision masks. Download the example file here.

The concept is pretty easy:

Collision Group are the collision 'layers' that the object belongs to. Multiple can be selected.
Collision Mask are the collision 'layers' that the object can collide with. Multiple can be selected.

For example, if Ball2 belongs to Collision Group 2, but can only collide with objects on Collision Group 1 (through the use of Collision Mask), it will not collide with itself.


How to make tileable procedural noise texture?

Edit:
This answer describes achieving continuity by mapping 2D onto the surface of a torus. Now Blender has 4D textures, and you can avoid the distortion that introduces.

One way to avoid reflection as method of achieving continuity from u=1 to u=0, and v=1 to v=0, is to map u and v on the 2D tile from the surface of a torus embedded in the 3D texture space.
The parametric equation for the X,Y and Z of u,v on the surface of a torus, where u runs around the major circumference, and v runs around the minor circumference, is as follows. c is the major radius of the torus and a is its minor radius. u and v must run from 0 to 2 pi, or some variation giving a whole number of cycles.

X(u,v) = (c + a cos(v)) cos(u)
Y(u,v) = (c + a cos(v)) sin(u)
Z(u,v) = a sin(v)

Thanks to this answer on Math SE
Here's an implementation of that as nodes, expressing c as a multiple of a. The U and V nodes multiply the generated 0-1 X and Y values by 2pi.

whose output can be put through a mapping node for conveniently hunting down locations and rotations of the torus which give a desirable pattern..

with this sort of result:

There is a disadvantage of uneven scaling.. the inner radius of the torus is shorter than the outer, for u. For v, the radius is constant. But changing the ratio of c to a covers most anisotropy.
It's very possible that someone with better math than me comes along and improves / corrects this, but it's working so far.


How to see my Cycles render and blender render in Game engine

You can't use Cycles materials in the BGE; it uses something similar to the Blender Internal renderer with a few differences. You can still use the same model, though—you'll just have to change the material.


Blender game engine development directions?

Ton Roosendaal covers this in the Blender roadmap – 2.7, 2.8 and beyond

  What should then be dropped is the idea to make Blender have an
  embedded “true” game engine. We should acknowledge that we never
  managed to make something with the portability and quality of Unreal
  or Crysis… or even Unity3D. And Blender’s GPL license is not helping
  here much either.

If you want to develop a game today you can model assets with blender, but should better pick another game engine.


What does it mean when I click "Bake" and it says "no active UV layer found in object"?

Go to the node editor. ⇧ Shift+A to add image texture. Select your image. (No need to connect the node)... now try to bake and it should work. I'm not on blender at the moment but off the top of my head I believe the steps should work....


How can I calculate the acceleration of an object?

However, for that I need the time difference, which I don't know how to calculate.

You can use the second order finite differencing to approximate the acceleration. And by using a central differencing scheme you can achieve second order accuracy.

In Blender,
you can use FCurve.evaluate function to get the position of one object:

action = bpy.data.actions[0]
curve = action.fcurves[0]
# Evaluate object's position at time t
position = curve.evaluate(t)

And you can use central second order differencing to calculate the acceleration at time t:

def D(curve, t):
    h = 1e-4
    return (curve.evaluate(t + h) - curve.evaluate(t) * 2 + curve.evaluate(t - h)) / (h * h)

Note that you have to use backward or forward differencing scheme at boundary of an action curve since the value at t + h or t - h may not be defined there.

Also note that you will see an extraordinary large acceleration at jump point, which may be a problem when you build animations from the calculated acceleration.


You can't import these module from the Python Console, they're only available when the bge is running. Add your script to a python controller logic brick.


Unwrap command works for mesh objects only

Sapling add-on currently create Curve-type objects which must be converted to mesh with the Alt+C shortcut before performing unwrap.

Unwrap is an operation that requires faces in order to be performed: beveled curves, text objects and other types,thought they appear as solids objects, they don't strictly "have faces". Blender makes an on-the-fly translation for us to see them, but the object really is only defined by what you can edit (curve control point, strings... but no faces!)

If confverting the curve to mesh is not suitable for your work you can consider the option to see if another kind of UV mapping can be used. See related question: Adding a texture map to a beveled curve or path


You are moving the wrong bone , the Target is the bone that is used to move the IK , Thats why it is called Controller bone


Python: How to connect shapekeys via drivers?

The line skey_driver = key.driver_add('value') will create a new driver, any existing driver will be replaced by the new driver.

You can delete an existing driver before creating a new one using key.driver_remove()

Note that replacing the driver with a new one will leave the driver variables behind, you can remove driver variables with skey_driver.driver.variables.remove(var) or all of them with -

for v in skey_driver.driver.variables:
    skey_driver.driver.variables.remove(v)


That line indicates a parent child relationship.

Read: How do I “parent” objects? or The corresponding Blender Manual page

To clear the relationship use Alt+P