Reassign position and scale of the navigation gizmo

I'm answering myself in case this helps anyone in the future. The file to edit is \blender\source\blender\editors\space_view3d\view3d_gizmo_navigate.


You can begin with a perpendicular plane:

Bevel the angle with CtrlB:

Select all and press AltE to extrude the faces along the normals:

Scale if necessary, select the edges and bevel again to round the angles:


How to access tools from the tools panel in blender 2.8

I think this is what you are looking for

Good Luck


Choose your vertex group in the Density Tab in Particle Settings


How to UV Unwrap and Scale UVs with Python (while in object mode)?

Look for python code in bl_operators

Some default blender operators have their python code available in 2.79/scripts/startup/bl_operators in this case uvcalc_smart_project.py .A quick peruse of the code and you will see that most of it can be done in object mode, by passing operator properties to the main(...) method. . Except "aspect correction"

print("Smart Projection time: %.2f" % (time.time() - time1))
# Window.DrawProgressBar(0.9, "Smart Projections done, time: %.2f sec" % (time.time() - time1))

# aspect correction is only done in edit mode - and only smart unwrap supports currently

Quick test in console, in object mode (defaut scene camera view) (Please also note that even though blender uses radians as its rotation unitprojection_limit appears to use degrees going from 1 to 89. So pass it  30 rather than radians(30)

>>> from bl_operators.uvcalc_smart_project import main
>>> main(
main(context, island_margin, projection_limit, user_area_weight, use_aspect, stretch_to_bounds, )
>>> main(C, .02, 30, 0.03, True, True) # not radians?
Smart Projection time: 0.10

producing

Scaling UV is pretty trivial see python templates > Operator UV simple  Script below doubles the size of object mode context object UV.

import bpy
import bmesh

def main(context):
    obj = context.active_object
    me = obj.data
    bm = bmesh.new()
    bm = bmesh.from_mesh(me)

    uv_layer = bm.loops.layers.uv.verify()
    bm.faces.layers.tex.verify()  # currently blender needs both layers.

    # scale UVs x2
    for f in bm.faces:
        for l in f.loops:
            l[uv_layer].uv *= 2

    bm.to_mesh(me)

Note:

bm.faces.layers.tex.verify()

is no longer supported in 2.80 and will need to be removed.


Motion tracking stops at a certain frame before the end of the shot

If the tracker is very close to the edge, the automatic tracking will stop. It cannot keep tracking if there are no pixels to fill the tracked area.
Either offset the marker (GG) or create a new one and join both, else you can manually position the tracker for any given frame.


Blender is not rendering my animation in Cycles, even though it is set to that, why?

If there are image strips in the Video Sequencer editor, Blender ignores the scene and the cameras, rendering the image strip instead. Deleting the image strip or unchecking the "Sequencer" checkbox should solve your issue.

Generally, however, I'd recommend that you process the image strips in a different file from the one you used for rendering.


Hotkeys have changed, how can I fix this?

Probably if you go to Edit >>> Preferences >>>> Load Factory Preferences

Hope that Helps

Good Luck


What is fastest, rendering on a CPU or a GPU?

Rendering is an extremely complicated process, thus the actual rendertime of a given scene depends on vastly more things than the actual hardware. Things such as scene size, shader complexity, and poly count (as well as dozens and dozens of other factors) all play into rendertimes.

Since there are literally hundreds of factors that affect rendertimes, it's really impossible to say how long a given scene would take to render.  Even if you knew all of the major factors it would still be virtually impossible to quantify these and say "it will take X hours to render, without actually rendering it.

That said, you can somewhat accurately generically compare the relative speed between two pieces of hardware.  So most of the time the gtx980ti will be considerably faster than most any CPU.

That said, I'd say save your money for now.  Your current specs are pretty darn fast, rendering is just a complicated process and will take time no matter what your specs are.  In the future I'd probably upgrade the GPU to an NVIDIA, but it won't be massively faster (unless you go for a Titan or m6000 or something like that). Compare your times to this article, it's a year old but still fairly relevant.

You may also want to consider going for two less powerful GPUs (provided your motherboard is SLI capable) and getting them one at a time.


"wire_mat_gui" add-on, how to render wireframe with visible edges only?

I wasn't able to produce a satisfactory render using that addon. I'm not sure if it's a bug in how the script was written, or if it's a bug in Blender, but I noticed that the extra edges show up when you move around in the viewport. If you access the material settings, and modify some of the values of the material, the extra lines disppear until you move in the viewport again.

That being said, rendering a mesh with its wireframe can be accomplished using Blender's built-in modifiers. Start with the default scene, and subdivide the mesh a few times:

Next, tab back into object mode, and scroll to the "Modifiers" tab. Click "Add Modifier" and choose "Wireframe":

When you do this, the mesh will change to show only the wireframe. However, you want to have the original mesh and the wireframe, so uncheck "Replace Original" in the modifier panel:

Next, scroll to the "Materials" tab, and add a new material to your object. This material is going to be the material for the wireframe. So now, you should have two materials, the default material, and the material you just added. Change the new material to whatever you want, in this case, I've created a red material:

Finally, scroll back to the "Modifiers" panel, and increase the "Material Offset" to "1". An offset of 1 will mean that the wireframe uses the second material from the material tab. So, if you had a bunch of other materials applied to your object, and the material you wanted to use for the wireframe was the 10th material in your list of materials, you would set "Material Offset" to "9". Now if you render, the wireframe will be rendered using the new material you created, and the cube will be rendered using the default material:

Does that help at all?


How to create a switch Node that recognizes if a texture is connected to the node input?

Here are three ways to do it:

Python Nodes API: with Python nodes like mentioned before, you can create a smart/dynamic node, that can change values depending on Python properties, like if an image is inserted or not

if you don't want to use PyNodes, you can use drivers, here's a simple driver that does what you need (change "Image Texture" in drivers panel to the name of your Image Texture Node):

if you plan to have such functionality inside a node group, you could set a chosen default value for a socket (a negative value would work in this case), then if nothing is connected to the socket, it would have the default value, which you compare and detect, if something is then connected to the socket, that would change its value, now the compare would return 0, it all works out, because Image Texture Node won't produce a negative value.


How to repeat an Image Map in blender 2.8

You might look into this, seems like a lot of nodes for what was just a checkbox. Hopefully someone else has a better answer.
Is there a way to do mirror Image mapping in EEVEE?


The simple answer is that you don't.

These patches are not intended for the end-user. They are intended to be used by developers to modify the source-code of Blender.

If you feel that you've got the skill-set to modify the source-code, more power to you! Unfortunately, most of us won't be much help. You'll get better support from the developers over at the Blender development project.


The quickest way would depend, not on whether the cylinder-object is aligned to the world axes, but on whether the cylinder's mesh is aligned to its own Object (Local) axes.

If the cylinder is aligned to its own axes:

For an absolute length, you can set its size in that dimension in the 'Dimensions' panel of the properties region of the 3D View, in Object Mode. Beware. This will scale the object's transform matrix. It's probably desirable to  CtrlA > Apply the scale, to bake it into the mesh.
To move one end by a numerically entered amount in Edit Mode, you can just set your Transform Orientation to 'Local' , and (supposing the cylinder was created with Z along its length) hit  GZZ [the number].

If the cylinder is not aligned to its own axes:

You can create a Custom Orientation from a longitudinal edge. Select the edge, and hit CtrlAltSpace.  (I usually check 'Use after Creation' and 'Overwrite Previous'.) Now any translation or scale you make with GYY or SYY will be in that edge's direction, and will accept numerical entries.

For absolute transforms, you can always create a jig. Just duplicate, for example,  a single vertex at a known zero point, then transform it to the full extent numerically in the desired Transform Orientation, and use it as a snap target for translation, scale, or rotation, before deleting it.


Baking physics on several machines / Combining cache

As far as I know this is fundamentally impossible.

Physics simulations are sequential data, that means each frame depends heavily on the previous one.

To calculate what happens at any given moment you need to know what happened before, so you must have position and status information about every intervening element in the simulation to know where they were and calculate where they will be next.

Without that you can't have just pull out of thin air how a simulation looks at a random point in time without knowing exactly how it was an instant before.

This makes it impossible for a computer to calculate "frame 100" from scratch without having frame 099, or 099 without 098, and so on till the beginning of the simulation from a known "rest position".


You could try the modeling cloth addon. It has an inflate option and I've seen a lot of images of people making inflated objects with creases like that.
https://www.youtube.com/watch?v=yHGz7nEI23E
https://github.com/the3dadvantage/Modeling-Cloth


Is this a hack?
First, give your object a vertex group, set to a very low weight for all vertices.. mine's called 'Shell_VG'
Give your object an Edge Split modifier, on all edges, followed by a Solidify Modifier, set to fill the rim, and weight the 'Shell_VG' group.

Then a Displace modifier along normals to shrink the faces, and a Mask modifier aimed at the shell vertex group, set to a higher threshold than the one you set originally.

For the pink result:

If you don't mind solid faces, you can cut out all the masking steps.


How i can remove transparent ball from model?

look's like you have your clipping value to low.

the clipping can be found in the n panel or in the camera tab for the camera.


Is there any way to duplicate bones radially?

Just an idea... you can dupliface the armature:

Here I used a cylinder: the number of faces will make the radial distribution.

Once original armature is ok, you need:

to select the cylinder and make duplicate real
to select the duplicated armature and make them single user
then join them:

Though, I don't think there is a mean to duplicate the eventually created animation on the original armature by this way...


UV mapping artifact - Black edge (alpha area)

Planes with transparency on them will always look this way in the viewport.This is because, as a way to be able to render the view port quicker, blender simplifies the transparency: instead of rendering the gradient from solid color to transparent, it renders a gradient going from solid color to grey, and only the fully transparent parts of the image will show the face behind them. This is expected behavior for the viewport.

When you render the scene, it will render the transparency as expected.


What is the best way to connect two cylinders at a 90 degree angle?

Select the edges. Ctrl + E  or right click or Edge Menu > Bridge Edge Loops > add number of cuts and select Blend Surface. Adjust Smoothness as you wish


You can also do a "hard cut" (SH-K) after frame 115, shift the right strip that's now separated a little (to the right), hard cut it's 1st frame off (frame 116), and drag what's left to the left again to join it with the left strip.  The two strips will play and render in sequence, and importantly, without frame 116.


Can't export to .wrl after I have changed the pose.

The vrml export addon only exports the active mesh object, if the active object is not a mesh object then the export option is disabled.

After using the armature to re-pose your object you need to re-select the mesh object to be able to export it.


Use the dependency graph.
import bpy

# get the object
obj = bpy.context.object

# get current dependency graph
dg = bpy.context.evaluated_depsgraph_get()

# get the object as currently evaluated
e_obj = obj.evaluated_get(dg)

# get the particle system
ps = e_obj.particle_systems.active

# and count
print(len([p for p in ps.particles if p.alive_state == 'ALIVE']))

As said in the documentation:

This example demonstrates access to the evaluated ID (such as object,
material, etc.) state from an original ID. This is needed every time
one needs to access state with animation, constraints, and modifiers
taken into account.


You have joined cubes into one object, but in Edit mode vertices are not merged.
Hower with a cursor above a vertex and hit L (Select Linked) ...

your mesh is selected partly - means vertices are not connected. This is the reason why it falls as separated.

it should behave like this ... I used Remesh modifier > Blocks to quickly generate merged cubes at similar density like yours ...

BTW - Your topology is too uneven and dense.
Wire density has essential impact on simulation result.

With the same Softbody setup, but low poly resolution ...

Here after Limited Disolve X operator ...

Note: You have to Apply Remesh modifier before simulation, because Softbody sim is calculated first and Remesh after - so it wouldn't be taken into a count in simulation.


BGE: How to make things based on time(definite) instead of frame(relative)

The BGE is designed to run with constant frame rate (default 60).

This will work pretty well as long as

you do not disable the constant frame rate
the processing time per frame does not exceed the available time per frame


Problem mixing 2 transparent shaders as two different layers

You have to delete the last mix shader node and one of the transparent shader node, and feed that input with the output of the other shader, so that when the top "layer" is transparent you'll see the bottom "layer", and when also the bottom layer is transparent you'll see the background checker.


So you don't want the top and the back to be disconnected from the front, right?

In that case, clear the seams from these two edges I painted blue:

You can do so by doing in Edit mode: Right click + Clear Seam. Then, unwrap the UVs again.

Notice how this model looks if I mark the top edges as Seam:

And notice how it looks by clearing the seam:

When you mark a seam you are telling Blender it's OK to disconnect that part of your object from the rest, so only mark them in places that you don't want connected on the resulting UV mapping.


v2.8 cycles - weird color change in Fire Simulation when over background

It is not a problem or a bug as you may think - the smoke is translucent/transparent so the light passes through it and you see what is on the other side. In this case - a plane that appears to be gray. Hence the change in color.
I guess you could increase the smoke density so the light wouldn't pass through it.


Are you refering to this?

Boundary Loop

Reference

Mode: Edit Mode –> Edge select mode
Menu: Select ‣ Select Boundary Loop
Select Boundary Loop does the opposite of Select Loop Inner-Region, based on all regions currently selected, it selects only the edges at the border(contour) of these islands. It can operate in any select mode, but when in Face mode it will switch to Edge select mode after running.

All this is much more simple to illustrates with examples:

The steps I took to use Select boundary loop in version blender 2.77

Hit Tab to enter edit mode.
Make sure you are in select face mode.
Select the faces to be converted to edge boundary selection.
Hit Ctrl + E and select "Select Boundary loop"
That's all.

If your command isn't there, make sure you downloaded the official release.


Get bone rotation in pose mode using Python

First note that bones have two representations within blender, the EditBone data represents it's static rest position within the armature while the PoseBone is the animated bone data that you would be moving around. The edit bones are stored in obj.data.edit_bones while the pose bones are in obj.pose.bones.

The rotation_mode value of a pose bone is used to switch between using rotation_euler, rotation_axis_angle or rotation_quaternion. These three rotation values can be seen in the bones properties and will show values without any constraints being applied. Note that euler values are stored as radians so you may want to use math.degrees() for the display value. Also the W in axis angle is radians.

The pose bones matrix value should give you the world position of the bone after constraints and drivers have been applied. You can get the bones euler rotation with bone.matrix.to_euler(). If using bpy.context to get the bone, you will find that bpy.context.active_bone.matrix will give you a matrix of zeros and ones while bpy.context.active_pose_bone.matrix will give you the matrix that you are after.

You can use a panel to watch the rotation of a bone -

import bpy
from math import degrees

class SimpleBoneAnglesPanel(bpy.types.Panel):
    bl_label = "Bone Angles"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'

    def draw(self, context):
        arm = context.scene.objects['Armature']
        bone = arm.pose.bones['Bone']

        mat = bone.matrix.to_euler()
        row = self.layout.row()
        row.label(text='X: {:.3}'.format(degrees(mat.x)))
        row.label(text='Y: {:.3}'.format(degrees(mat.y)))
        row.label(text='Z: {:.3}'.format(degrees(mat.z)))

bpy.utils.register_class(SimpleBoneAnglesPanel)


How can I animate a 2D face rig on any 3D object?

First a simple solution with the UV Warp modifier. Then an alternative with Image Sequence as explained here by SouthernShotty.

UV Warp solution:

Create a PNG, with transparent background, of your facial expressions:

Give your object a material. Assign another material to the face area: Unwrap this part, add a UV Map node with the new UV map loaded, plug it into an Image Texture node, open the PNG, plug the Image Texture into a Mix Shader, plug the Image Texture Alpha output into the Factor of the Mix Shader, plug the skin material into the other input of the Mix Shader.

Create an empty at the same position as the head. Give the head a UV Warp modifier. Choose X and Z as UV Axis, From > Choose the head object, To > Choose the empty.

Create a bone at the exact same position as the empty. Parent the empty to this bone (the bone will probably be part of a whole armature):

Now the bone controls the empty and the empty controls the position of the PNG. To save all the different expressions, you can use the Pose Library in the Properties panel > Object Data. Move the bone in Pose mode and press the "+" button to save the pose. Continue until you've saved all the poses. "+" button is also used to replace an existing pose. Use the Apply button to call a pose. Give each pose an appropriate name (Smile, Sad, etc...).

Image Sequence solution:

Create your facial expressions on transparent (alpha) backgrounds, name your images 0.png, 1.png, 2.png, etc:

Select the part of your mesh where the expressions are supposed to happen, unwrap and give it its own material. Create an Image Texture node, click on its Open Image button, select and load all the PNGs, plug the node's color output into a Mix Shader, use the other Mix Shader' socket for the skin color you've used for the rest of the head, plug the Image Texture's alpha output into the mix factor socket so that you can see the expressions over the skin:

When you've imported your PNG, the Image Texture node has automatically switched to its Image Sequence mode. Set the Frames value to 1. Now you just need to create some keyframes on the Offset value to switch between the different images along the timeline. The Offset begins at 0, so Offset > 0 will be image 0, Offset > 1 will be image 1, etc. In the Dopesheet, once some keyframes created, press T and choose Constant Interpolation so that each keyframe switches directly to the image you want.

It should work:


How Can I Close This Gap Around This Deformed Cylinder?

Some Suggestions .. Not a tutorial
Torus with extrusions, vertex groups, shrink wrap.

Here is a low quality facsimile. I will write some simple things and not enough. Loop tools was shown in another link above.
The yellow cylinder.  The turquoise torus which is modified in edit mode.  So clearly the torus allowed fitting to the cylinder more easily. It has enough vertices for a nice fit. [Extrude] was used to produce the giant extrusion to the right. Then [Loop Cut] was performed to add the grid of vertices so that area can be formed.
The red mark on the right show 5 edges meeting like a box corner meeting a floor, produced by extrusion. A ring was selected and a [vertex group] was created.  [Shrink Wrap Modifier] was added with the Cylinder as a target and is depicted above. If you see terms in [] you do not know, you may want to see a tutorial. So now the vertices will conform to the cylinder when they are moved up (grabbed).  [Proportional Edit] is used. One vertex was selected and raised on the z axis. Nearby vertices followed in a smooth edit.
To the left some other vertices were chosen and put in a vertex group.  A shrink wrap modifier was added, with the box as target. This was added to show straightening an area. Clearly you can straighten an area in many different ways.  Note the red mark on the left where 4 edges meet.  To show a modelling [error], an extrusion was not used.  You can see the diamond shape stretched which you might not want.  No loop cuts were used, just to identify areas.  You may only need on shrink wrap.
I left big gaps in the visual .. you can reduce the gaps.  Please inspect and correct and optimize this work.  You can do better work than this.
Finally one area scaled.  Vertex group created on side and a Shrink Wrap.  You can press [apply] for modifiers.


How do I get lit textured materials in Multitexture BGE?

Unwrap the UV texture
Add a material
Check "Face Textures" under Options in the materials panel.

You may now adjust the spec.  Make sure the textures panel is empty.


Pixelated/Blocky Effect in Smoke Render in Blender 2.82a?

TL;DR,
Use png, exr, jpeg with high quality... image format to save as sequence and encode them in other program to video. eg. Adobe Premiere (Media Encoder), DaVinci Resolve

Depend on your video encoder, keep in mind that most of the video format are lossy-compressed by default, which means some data are actually loss in the video from the source.
And most of the encoding algorithm assume that one frame should be similar to next frame, to reduce the space requisition for similar color. So if your explosion make "fast and high dynamic color change". Your video will perform a low resolution, or blur, chunk image sequence, if your video bit-rate is set as a relatively low value.
You can set your H.264 render parameter to lossless to suppress that mosaic effect:

Or you can use AVI Raw format to save a BMP-sequence-like video format.


Blender game Engine collision sensor, property value

I fixed the problem, i had to activate the TRUE level triggering, now it works


There's apparently a bug in the current version of Blender (2.78c) which won't allow users to use spritesheets as animated textures.

Try this method to get around the bug
https://www.youtube.com/watch?v=hIQ0xYTAgt0
(Video not by me)


Create a half circle by attaching a colorramp to a spherical gradient and removing the bottom half greater than math.

Make these nodes into a group. CtrlG

Create a square by clamping X and Y coordinates to [-1, 1]

Rotate the items with vector math operations or mapping nodes.
Squash the square into a rectangle and place it in the center. Use the half circles for top and bottom.

We can improve this setup by using a Radial Gradient and plug it into a colorramp to control the half circle, then we can increase the angle.


How to convert Raw image texture baked from Blender to sRGB color space

So the difference between Linear, Non-Color and RAW Image Texture node's Color Space options seems to be subtle:

Linear option is for linear color space. This means it is color information and will be treated accordingly if color space conversions are needed.
RAW is still color information, however it is color information that will not be managed in any way and will be as is. It will not go through any color transforms so in Blender's context it will be linear, because that's what Blender uses internally for rendering and calculations.
Non-Color is information that is not color and will also not be managed as color by color management at all. It will not go through any color transforms and will also remain linear.

You can see that Non-Color and RAW is exactly the same thing in all practical aspects except meaning, while Linear and Non-Color differs in the way Blender should treat the data.

So if you know how to work with Linear color space, the same should work for you with RAW. If you apply gamma of 2.2 to it you will get an approximation of sRGB color space. sRGB is not exactly the same as gamma 2.2 though, but this does not seem important in this context. See https://www.nayuki.io/page/srgb-transform-library for example if you want to know more about it for some reason.


How to Create 2-D to 1-D Text Retraction Animation

Animate the offset value.

With the text slected, got to the properties panel, under the text tab(the one with a F icon),  then under the Geometry subsection, animate the offset value.


Simply:

add a plane and set it to rigid body passive
add a cube somewhat over it, set it to rigid body active
just rotate the cube it a bit so that its bottom face is not exactly parallel to the plane... reality is never absolutely perfect. Adding to that, or otherwise, there are settings to make the plane more "bouncy" if you prefer: look under plane and cube rigid body settings and enhance "bounciness" (try 0.2- 0.4 to start for the cube, try 1 for the plane) at your taste.

Done, press ALTA

Obviously the bonciness depends also on the falling object shape: try a sphere...


How would I make a group vertices all the same distance from an Axis line?

A Cast modifier, set to 'Cylinder', with a Factor of 1, aimed at a vertex-group made of the selection you show, should do the job.

The Cylinder will be formed around the local Z axis of your object, or that of a control-object you allocate in the modifier.
It will be formed by pushing vertices outward toward the given radius. If the minimum is too large, the modifier may have to be applied, and the vertices scaled back to the desired final size.
The vertex Z-coordinates, in the cylinder's space, are not affected.

These tubes have been solidified for illustration.

Settings:


Hiding vertices doesn't work in sculpt mode

Yes, thankfully there is a way, though it’s not quite as flexible as edit mode vertex hiding. Has to do with something called “face sets“ if I remember correctly. Look around in the menus for hiding selected faces, and see if you can figure it out. I personally didn’t get very far, but I was able to get something done thankfully.


Blender 2.83 GPU render slows compared to CPU

Issue solved.
I was using Blender 2.83.1 version
but 2 days ago new version came and i installed that and render times are around 4 5 minutes which is perfect.
So this was some kind of bug that is fixed now by blender.


If you want to use an armature, follow the Batfinger's tuto here.

If you want to use a simple Curve modifier, you need to make sure that the position of your object on the curve. What you should do is:

Choose a vertex in your curve, where your animation is supposed to begin.
Make it the curve's origin.
Make it the curve’s first point. To do so, enable the Bsurfaces addon, select the vertex, in the Tools panel > Tools > Bsurfaces > click Set First Points.
Now put your dolphin object at the exact same point.
Move it on the right axis so that it follows the curve.


Blender smoke sim explosion just ends up like volumetric fog

You need to tell the Principled Volume node where to get it's measure of the 'density' of the domain from. You can do this by either feeding a value into the 'Density' socket or you can fill in the 'Density Attribute' to indicate it should be taken from the smoke domain 'density' attribute.
In your case you should be able to simply click on the 'Density Attribute' field and enter 'density' (all lower case).

Changing the 'Density' value (just above the Density Attribute) will adjust overall density of the smoke (it acts as a multiplier).


Why is my image not showing up after UV unwrapping?

Have you possibly tried applying the texture to the material AND texture tab? How about with the same texture? One way to make sure you have the right texture is to, instead of reopening a file, just select the same file by clicking the arrow next to it. Hope this helps, sorry for not being a teensy bit more specific.


try pressing Y 2 times again (total of 3 times), until you are free to move the new geometry freely... every time you press Y you set other contraints for the transform.

after E you are "grabbing" along the face normal.
pressing Y 1st time puts you in "constraint to global Y"
pressing Y 2nd time puts you in "constraint to normal Y"
pressing Y 3rd time puts you in "no constraint at all"

you can see a feedback of these changes in the lower left corner of the 3d window, where coordinates change while you are moving...


Blender internal - pure white plane with shadows/gloss

You could try to use "Shadows Only" option in the material's shadow settings

and set horizon color to white in the World tab.

The result looks like this:

This is the blend with such simple setup (I have also enabled Ambient Occlusion effect in the World settings).


How to keep a transformation after "set parent" if "clear and keep trasformation" doesn't work?

Shift + P   and choose Clear and Keep Transformation.


Per shader:
Plug it it into the Height input of a Bump node (ShiftA>Add node > Vector > Bump)

The above node setup will only bump the diffuse part of the shader, simulating a bumpy diffuse surface coated with a smooth glossy "glaze" layer.

Entire material:
If you want to apply the same bump mapping to all the shaders in your material, just plug it into the Displace input of the Material output node:

You'll notice that now the bump is applied to the glossy shader too:


Can't animate the scale of objects changing

You need to insert keyframes for changes to values.

Go to frame one, scale the object to 0.001 and with the mouse cursor in the 3d view press I > Scale. Now all frames will have this value.
If you change to frame 20 and scale it to 200, you will notice the scale property being orange. Orange means that this value is different than the keyframed one and will be lost after changing frames.

Press I > Scale again to insert another keyframe for this value.


how to scale an object that uses a mirror modifier?

When are you scaling the object you have selected all vertex, all faces so it's scaling through the all plane which is not yet connected to the mirror object. It's ok to use clip checkbox and deselect it after apply every change you want to. To the first question - you've also checkbox "Y" below "X" in the modifier.


fluid simulation controls - fluid overwhelms collision objects -

Try raising the walls? Also, the resolution of the fluid looks very low. That could be causing problems with this. Go to the Domain, and increase the resolution divisions.


How to attach eye armature to rigify armature?

Rigify armature is really confusing with all those names so what I always do to parent head with new bones for the eyes is to select head bone in edit mode, add a new bone and then add other bone that is going to move one eye and then do the same for the other eye.

After that select the bone that is in the middle connecting eyes with head and delete it. You will have eyes parented with the correct bone head.

I know there are probably other way to do that


How to remove black box from my cloud, cycles

Your max transparent bounces setting is set to 0 in Properties > Render settings > Light Paths:

This setting limits the number of transparent surfaces a ray is allowed to pass through. Setting this to 0 means rays are not allowed to pass through any transparent surfaces, rendering black instead.

Set this to something greater than 0 (e.g. 8) and all should work as expected.


Automate connections in 2 columns of nodes

Partial solution (adding reroutes to all unused inputs and replacing them) :

If you prefer to read or didn't understand this rushed video :

So you have a bunch of nodes and you want to add reroutes to their inputs

add any node (doesn't matter which one since you'll delete it later)
move it on the left of your bunch of nodes
select your bunch of nodes and the new lonely one which you set as the active one
press K (with Node Wrangler enabled) to connect the lonely node to the bunch of nodes.
select and group the entire node tree except for the new lonely node which stays outside
in the group, Shift + left-click drag on the group input links to add reroutes on them
Tab to get out of the group
Alt+G to ungroup it
delete the lonely node you added previously
reorder your reroutes properly if some are not in the right place
Shift+= to arrange them perfectly

Voilà. Now you can replace those reroutes by any node with Shift+S. And if you need them to have specific parameters, don't forget Right-click > "copy to selected" to apply your changes from the active node to all the selected ones.


How can I make a mesh have holes during segment creation

If i understood the question here is the answer

Import the autocad file

Convert to Mesh

Press W key to Remove doubles

Press delete and select limited dissolve

Press Alt+F to fill the faces

Once again press delete and select limited dissolve

Select the Faces and extrude and Press Ctrl+N to flip Normal


Blender 2.81/2.80: How can I change the color of light of a spot - nodes seem to have no effect?

Works the same for me in 2.8 & 2.81-

So the answer is: in the light panel. Where my screen-grab shows the blue colour swatch, just under the type-of-light buttons.

I'm guessing you chose 'use nodes' for the light with Cycles as the renderer, if you notice my screen shot does not have the option in the light panel (as I'm using Eevee).
I had to chose 'use nodes' with cycles as the renderer before switching to eevee.
So the nodes should, by rights, disappear / become ghosted or whatever when you switch to eevee, but obviously do not... Somewhat annoying / confusing!

Help menu / report a bug (or a 'paper-cut' or whatever!)


Deselect all objects (also on hidden layers)

You can press ` which is usually found immediately to the left of the 1 and directly above TAB.

This will make every layer visible so now using a will function as you would like it to.

Or you could just select something using a mouse/pen click, this will also release any hidden layer selections.


You can animate the renderability of the object.

Move the mouse over the camera icon on the outliner and set a keyframe (just press i or right-click and select insert keyframe) then move to the frame where you want the object to disappear, disable renderability by pressing on the camera icon and set a new keyframe.

Note that the interpolation for visibility is always Constant.


Snap vertices to grid on some objects in my model is broken. How can I fix them

Your transform in the screenshot is not set to “Increment + Snap to grid,” but rather “Snap to edge.” Change this and see if it works right.


To optimize the viewport speed, by default Blender does not show all edges in wireframe mode.  To force it to draw all edges on a particular object, go to the object data panel of the properties view and check draw all edges under the display rollout.

Here is an example:


how to extend an object just on one side along his own edges?

You can still use edge slide to do this.

Select the end face (or its edges or vertices)
GG.. edge slide
Draw the face inwards a little way, making the piece shorter as you described in your post (this establishes the slide directions)...
Now hold down Alt, or tap C releasing the clamp. You should see rays extending the longitudinal edges.
As long as you are holding Alt, you can slide the end face's vertices anywhere you like along those rays.

Unfortunately, snap doesn't work with GG. If you wanted that, too, I think you would have to break the operation up, separately moving components along Custom Orientations derived from the longitudinal edges.


I guess by "perfect view", you mean a view without perspective (aka Orthographic view). You can use NUM5 to switch between Perspective and Ortho.


Convert an EXR render from scene-linear colorspace to CIE XYZ

It isn't straightforwards as Cegaton notes.

You could abuse Blender's ridiculous OCIO integration to achieve this however. Save the file as an EXR, and add the following stanza to the OpenColorIO configuration in datafiles/colormanagement:

 - !<ColorSpace>
    name: One-Way XYZ
    family: Input Special
    equalitygroup: ""
    bitdepth: 32f
    description: |
      One way transform to save an XYZ EXR.
    isdata: false
    allocation: uniform
    allocationvars: [0, 1]
    to_reference: !<MatrixTransform> {matrix: 1.0,  0,  0,  0, 0,  1.0,  0,  0, 0,  0,  1.0,  0, 0, 0, 0, 1]}
    from_reference: !<MatrixTransform> {matrix: 0.4124564,  0.3575761,  0.1804375,  0, 0.2126729,  0.7151522,  0.0721750,  0, 0.0193339,  0.1191920,  0.9503041,  0, 0, 0, 0, 1]}

Note that this is a one way transform! Don't use it for anything else. It also assumes the file was saved as default scene referred linear in an EXR.


Rendering low poly model to 2D, make facets stand out more

You have to create contrast in your lighting to bring out the facets. Lighting from the exact same direction of the camera does the opposite, it makes everything flat.

This image I created by starting with your blend file and then:

Removing the Front Light object
Removing the Front Light material from the Top/Bottom Light objects
Increasing the emission strength
Moving the light objects towards/away from the mesh object until the lighting is nice

By adding a bit of glossyness to the mesh material we can bring out the facets even more:

This is the material node tree:


Editing armature in edit mode mess up pose mode

You should not edit the bones in edit mode after animating them, do that only if you want to modify the rest pose.
If you want to pose the bones than use Pose mode. Editing bones after posing will break the pose because you have modified the original rest pose and the transformation matrices of all the bones would evaluate a wrong pose. because poses are relative to the Rest_Pose.

you need to setup your rest pose while in edit mode (or in pose mode and use  Apply Pose as Restpose) and then proceed to posing the character, without modifying the rest pose.


How to reset the angle of rotated view without a numpad?

Start rotating the view holding the mouse scroll, then press and hold Alt button, while still moving the mouse. It will very quickly adjust the view as desired.


Does Blender have a "distribute evenly" function?

You could add a Copy Location constraint to each of the intermediate objects (with each of them initially positioned at the same point as the original) with the 'target' set to the last object, and then adjust the constraint Influence appropriately - ie, 0.25, 0.5, 0.75. This will distribute the intermediate objects at the correct spacing between the original and the last.

You could do the same with a Copy Rotation and Copy Scale constraint to have the intermediate objects similarly blend those attributes. Changing the Location, Rotation, or Scale of the 'final' object would then cause the intermediate ones to automatically move, rotate, and scale to blend to the final location/rotation/scale.


Here you go:
https://youtu.be/9airvjDaVh4
This will work with procedural materials, and eevee as well. You only need cycles for the baking part.
But basically, you need to put the image texture node you want to bake to - that's also selected - in the other materials.


Images as Planes, can not see the image on the plane

Blender does not support .GIF files you could e.g. export to .PNG from Gimp (PNG has also lossless compression and transparency) For all available formats see Formats.

The easiest way is to enable the Import Images as Planes addon. You find it in the menu: File / User Preferences.

After enabling use File / Import / Images as Planes

To see the texture you need to set the viewports shading mode to Texture:

Behind the scenes the addon has created a plane added a material with an image texture you can check this in the materials properties:

Note: For best performance the dimension of a texture should be a power of 2 (128x128px, 256x256px etc.)


How to start and stop movie sequence of image node at specific frame in python script?

Not sure how to answer but I am trying to access the start_frame parameter of a sequence strip in the VSE and my guess is it has to do with this thing called context. Looks like where ever the start_frame is being defined or allocated in it's parameter the context is where it is inherited.
So it seems you have to create a context which is local to your script so any called functions to "play at some start_frame" will be assigning the "start_frame" from a locally created/allocated "context".
See:
https://blenderartists.org/t/solved-add-effect-strip-transform-for-image-vse-lm18/688456/2
and Ctrl+F: You just need to set the context.

I have read however, this is not so good for when the local allocation is un-allocated you then have a reference which points to ??? or is broken and a potential for blender crash.
See:
https://docs.blender.org/api/current/info_gotcha.html
and Ctrl+F: # polygons have been re-allocated

Sounds like there is a start_frame being set from a GLOBAL context in your case so every start_frame=1 and that is a context you have to modify. Good luck I'm just trying to get:
bpy.ops.sequencer.effect_strip_add(frame_start=frame_start, frame_end=frame_end, type=‘SPEED’)
to use a frame_start from the selected strip and I don't know how to pass a frame_start parameter which equals the frame_start of the already selected strip without having to recreate a new context. I would imagine I could pass by reference but where is the allocated reference?

Anyway the answer is in the inherited context it seems.


How to show the panel with Geometry - Modification - Offset / Extrude

ah found it, partially through here:

https://spolearninglab.com/curriculum/software/3d_modeling/blender/blender_02.html

You simply have to click on that icon with two white dots connected with a curved line (have no idea how its called, when I do a mouseover over it, I get:

Type of active data to display and edit
Data: Object data
Python: SpaceProperties.context
bpy.Data.screens("Default") ... context

... which tells me absolutely nothing - but by the icon image, I'd guess this submenu is called "Curves"); and then you get Geometry panel...


How do I add a sun to the background without a texture?

It is kinde of easy to make it but it's harder to control.

Remember that you might get a sun mirror becuas of the power node. You can remove it with two more math nodes. One grater than 0 and use that to remove all negative values and it will remove one sun.


Actually the problem was that you had activated the Proportional Editing mode (which allows you to select the closest vertices), just deactivate it.


blender pickup up and dropping object -- setting visual keyframes just changes position?

This is the best method I've found pick up and drop and object using the aforementioned child of constraint with an additional copy location and copy rotation constraint on that same object. Then animating the influence siders of the copy location and copy rotation constraint to achieve the desired effect. There is no need to animate the child of influence slider using this method - you can keep the child of influence slider to full strength: 1.000.


Relationship between global vertex coordinates and mesh object's matrix attributes

Practical examples

Object.matrix_basis - If you want to modify the loc/scale/rotation directly, as a matrix - without having to worry about what kind of rotation is used - (Euler, Axis-Angle, Quaternion).
Object.matrix_local - Exporters where you want to write out parent relative transformation.
Object.matrix_parent_inverse - Any tools that handle the transformation relationship between parents and children. (Not used often)
Object.matrix_world - Any time you want to know the final transformation of an object after animation, drivers, constraints and parenting are applied. You would want to use this for example - if you are writing to a format like OBJ which doesn't store object transformations.


Holding an object with 2 hands in animation

I've solved my problem. Instead of using "Child Of" constraint, I've used IK and Copy Rotation constraints. Firstly, I've added an armature to my ball mesh. 1 bone for the general ball movement and the other 2 child bones for the hand/arm targets. Then I've added IK constraints to the forearms with child bones selected as targets. (Do not forget to change the chain length to 2-3. Since I was using the Rigify rig model, I've used 3 as chain length.) And finally, I've added Copy Rotation constraint to the hands and I attached the child bones to them.
For more information: https://youtu.be/Jv1InLG58GI


Mesh gets deformed when an array of spheres deformed along a curve :(

One of the easiest ways to make an object be duplicated along a Curve (path) is by parenting the object to the curve using (Follow Path):
1- Make sure the object and the curve's origins are at the same position, better to have the curve's origin at the beginning of the animation flow. Select the object then the curve, you need the curve to be the active selection.
2- Press Ctrl + P, choose Follow Path, this is different that Follow Path constraint, the only common thing is the name.
3- Select the object, go to Object menu, under Duplication, choose Frames and un-check Speed.
4- Select the curve, go to Curve menu, under Path Animation, set the amount of frames, the object will be duplicated according to this amount, check Follow, if you want your objects orientation to follow the curve.


How do I make an empty stand for a different group instance?

Group Instances can actually be created from any object type, but by default when inserted from the menu an Empty object is created.

Empty objects don't have any object data thus can't be "remapped" in the traditional sense. Group instances are stored instead as Dupligroup property on the object itself.

To change which group is being instanced by a certain object go to the Properties Window > Object Tab > Duplication and from the Group box pick the desired group.

To mass change on a large number of object select them all so that the object with the correct Dupligroup is active then use the Link Menu with Ctrl + L Make Links > Dupligroup.


How to average UV maps between multiple Blend Files

Use Texture Atlas addon to unwrap objects as one into new UV map, set up the UV islands scale as desired and use that map instead.

After activating the addon in the User Preferences, in the Properties editor, Render tab find Texture Atlas rollout and click '+' button to add new one. Options to make automated or manual unwrap will be available. For more control choose Start Manual Unwrap in the bottom of the rollout (.

What it does is the addon temporarily "joins" selected objects (they will be added into group and atlas will be created for them) and adds UV map with the same name per each one. With manual unwrap mode active, you edit objects as if they were one, assign seams as needed and unwrap. If you have UV maps already created select the meshes and in UV / Image Editor find UVs > Seams from islands.

Once finished, exit Manual Unwrap mode by clicking Finish Manual Unwrap button. Objects will again become "unjoined" ones.

Before unwrapping using the addon:

After unwrapping is done objects use UV map named the same for all of them and scale of the islands is set up properly:

The scale of the individual islands will be already equalized to correspond between all the adjacent objects.

Texture Atlas addon's page (the addon is already included in Blender).

Also read:
baking to multiple objects at once with multiple materials
Arrange UV maps of multiple objects without joining them


Can't rotate view around selected object (macbook pro)

Blender rotates its view around an invisible, non-consistent point in space, which can be changed through several operations, including shifting the view with shift+mmb.

You can precisely position that point by

moving the view to the selected object (view > align view > view selected)
centering the view to the 3d cursor (view > align view > center view to cursor)

You can add a single-button shortcut to both these options, allowing you quickly set the center point with high precision.


Objects Evade or Repell eachother in Animation Nodes

I divide this Repeller Effect into parts:

Offsetting the locations with multiple-object effectors.
Changing the direction of arrows with respect to the effectors'
location.

Part-1: Idea is, we offset the locations (grid-points) using the first effector then use those offsetted grid-points for next the effector with the help of reinitializing option of the loop node.

We want to offset location using more than one effectors (I'm using empties objects), so we need the Loop-Node and looping over effectors to get the location of each effector.

Then I have added the Vector-list (name it as grid-points) as "new parameter" in the Loop-Node and calculated the offset by taking the difference between the effector's location and grid-points using Vector-Node which I use as offset-list for the Offset-Node to repel the grid-points based on the Object-Falloff,

Now, select the Loop-Node then open the N-panel and reinitialize the grid-points and also enable the output option so that we can use these grid-points for instanced objects which are arrows in this case but you can use any object. Here is the complete setup for this part:

Part-2: To calculate the direction for the arrows, I take the difference of effector's location and offsetted grid-points. Now, to get the effect that arrows point toward the effector based on the distance from the effector (e.g. like in case of electric field), so we have to normalize directions w.r.t inverse of distances using Math-Node. You can also change the direction of arrows (i.e. point away or toward the effector) by changing the 1 to -1 in the Math-Node.

Next, we add these normalized directions for all effectors which we can do that by creating an empty Vector-list from "new parameter" then reinitializing it and enable the output option for further use in the N-panel,

From the outputs of Loop-Node, first, normalize the directions to one then connect them to Direction-To-Rotation node, and then to the Object-Transforms-Output Node,

The complete Node-Tree (I have added the Switch-Node to change arrow direction):

Note:- This Node-Tree also works for 3DGrid-Points.


In the first place you have to make a proper UV map of your object, this is a very basic and well known practice which will guarantee to you that whenever you open your model again (in every almost format) the textures will cover the correct faces of it.

The second thing that you have to take a look is Baking Textures (both in cycles and blender internal the procedure is similar but not the same).

After creating your UV maps and setting your material you will bake the render passes you need (you may not need baking shadows for instance) in separate files or merge them (one beauty pass) all of them in one single file.

These two steps are what are you mainly looking for, you will find a bunch of tutorials on youtube, on how to create UV maps (one or multiple - depending your needs after you understand the concept) and then baking the different render passes in textures.

The "Bake" panel is a place to start from


If you have one connected edge loop, you can use this script.

The mesh object has to be selected before executing the script.

import bpy

def CreateBoneChainFromVertices():
    obj = bpy.context.active_object
    if (None == obj):
        return

    if (obj.type != 'MESH'):
        return
    bpy.ops.object.mode_set(mode='OBJECT')

    edgesA = []
    edgesB = []
    for i in range(len(obj.data.edges)):
        ver = obj.data.edges[i].vertices
        edgesA.append(ver[0])
        edgesB.append(ver[1])

    chain = []
    chain.append(edgesA[0])
    while(True):
        current = chain[len(chain)-1]
        if current in edgesA:
            idx = edgesA.index(current)
            next = edgesB[idx]
            del edgesA[idx]
            del edgesB[idx]
            chain.append(next)
        elif current in edgesB:
            idx = edgesB.index(current)
            next = edgesA[idx]
            del edgesA[idx]
            del edgesB[idx]
            chain.append(next)
        else:
            if (chain[0] in edgesA) or (chain[0] in edgesB):
                chain = list(reversed(chain))
            else:
                break

    amt = bpy.data.armatures.new(obj.name + "_vBones")
    rig = bpy.data.objects.new(obj.name + '_vRig', amt)
    bpy.context.collection.objects.link(rig)
    bpy.context.view_layer.objects.active = rig
    bpy.context.view_layer.update()

    print(chain, "here we go")
    bpy.ops.object.editmode_toggle()
    for i in range(0, len(chain) - 1):
        bone = amt.edit_bones.new(str(i + 1))
        bone.head = obj.data.vertices[chain[i]].co
        bone.tail = obj.data.vertices[chain[i + 1]].co
    for i in range(0, len(amt.edit_bones) - 1):
        amt.edit_bones[i + 1].parent = amt.edit_bones[i]
        amt.edit_bones[i + 1].use_connect = True
    bpy.ops.object.editmode_toggle()

CreateBoneChainFromVertices()


What does the button next to the Pivot Point button do?

That button  is the manipulate center points option, which allows you to manipulate the origins of objects without affecting the rotation and scale of the objects themselves.

For example, if I scale these objects without it enabled, they are stretched. With it enabled, only the origins are moved (only affecting object location):

Note that with only one object selected, enabling this option will cause scaling or rotating the object to do nothing.


All faces (quads and n-gons) will be divided into triangles when they are rendered. Depending on the engine the solution for that triangulation will differ a bit. This is a normal thing. If you don't like how they are triangulated you will need to do it your self.


Z-depth of Microdisplacements and Adaptive Subdivision Surface

As Duarte mentioned, generated coordinates do not factor in the displaced mesh. So you need to get a Z coordinate from something that does. You can use either "object" coordinates (available from the texture coordinate node or the geometry node, their "object" outputs are the same) or "global" (aka world space) coordinates from the geometry node's "position" output. These do not rely on precalculated geometry, instead they simply use the shading point's location.

The difference between the two is that object coordinates are in "object space", meaning they account for the transformation of the object. That means they won't move when you move the object, which is good for animated objects (otherwise they might appear to "swim through" the texture). It also means that multiple copies of an object will always have the same texture, although that one may or may not be desireable. Global/world space coordinates are absolute and do not account for object transformations and locations at all. They're nice when you need to keep consistent texture locations across multiple objects (such as adding a waterline to objects below the level of your water mesh) or if you want different textures across multiple static copies of an object


Moving camera around in camera view in Blender 2.8

You can link the camera to the viewport and then rotate/pan/zoom as you are used to from the viewport - very handy!
Just

press N tp show right menu
view tab
view accordeon
view lock accordeon
check "lock camera to view"

All credits to this guy on YouTube...


Blender distorting objects when using move tool

You have Affect Only > Origins enabled in your Viewport Options. On some it just moves the origin point but maybe on others with modifiers that work in relation to the origin it can distort objects. Disable it.


The gradient is linear but not in the colourspace you are expecting - as evidenced by the following :

Here the Attribute node is making the Vertex Color (Col) available to the shader. This is split into separate RGB components and compared with the Generated 'X' coordinate (which runs from 0.0 at the left to 1.0 at the right of the cube).
The gradient is linear but the end points are not as you expect (ie, the blue vertical grid-line is at X=0.5 and the gradient line runs from about 0.05 at the bottom through to around 0.525 at the top). This is due to sRGB colourspace conversion.
Your values of 0.25 and 0.75 relate to those 'absolute' values of approx 0.05 and 0.525 when converted from sRGB into the 'true' brightness - the sRGB colourspace is intended to make the most of an 0-bit integer representation of the brightness to make it as visually diverse as possible - so values at the start/end of the range and compressed/expanded to suit what would be noticable when displayed on a screen to the human eye.
See https://en.wikipedia.org/wiki/SRGB and note the red line on the following graph :

Using the axis values at the bottom and right of the graph you can see that 0.75 on the x-axis converts to around 0.5 in 'intensity' - your Python code is applying the sRGB value of 0.75 and producing an 'intensity' of approximately 0.525 for the upper limit. Similarly, the lower 0.25 is being converted at the bottom end of the graph to a much smaller 'intensity' value. That 'intensity' is what is being linearly interpolated to produce your resultant vertex colour gradient - not your original sRGB values.


Order of buttons drawn not matching code order

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

    obj = context.active_object

    if obj and obj.active_material:
        mat = obj.active_material
        if mat:
            layout.template_ID(obj, "active_material", new="material.new")
            row = layout.row()
            row.prop(mat, "diffuse_color")
            row.prop(mat, "alpha")
        else:
            row = layout.row()
            row.label('no active_material')
    else:
        layout.template_ID(obj, "active_material", new="material.new")

Sometimes you have to be a bit more accurate about where a row should be generated. In your case the row is declared ahead of the template_ID, so any further additions to row will be added to that location.

The take-away here is that the line number of the UI elements like props and operators is less important than the line numbers on which the layout elements like row, col and box are first instanced. As with all good programming, variable names are important because they allow you to organize your thoughts.

While this is possible, it's asking for confusion:

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

    obj = context.object

    row1 = layout.row()
    row2 = layout.row()
    row3 = layout.row()

    # will display at the bottom
    row3.operator("mesh.primitive_cube_add")

    # will display in the middle
    row2.label(text="Active object is: " + obj.name)

    # will display on top
    row1.label(text="Hello world!", icon='WORLD_DATA')

The UI cookbook shows a worthwhile convention to follow, use extra identifiable postfixing for layout element names, row1, row2, row3 . etc. While reusing the variable row over and over again is handy, it tends to cause unnecessary confusion with more complex UI definitions.


Object Properties Viewport Display Color Question

I will iterate on the other answer and add that you can also use this color to add variation to different objects which use the same material, not only in workbench but also in Cycles and Eevee.
In this example I used the same Material on all three spheres. I just tweaked the Viewport Display Color of each object. This a very simple example but it can have multiple applications.

In this example I used the values of the color to add a roughness variation between the objects.

Actually, you can use the three channels of the color (Red, Green, Blue) to add even more variation ! This is all the same material but the Red channel drives the hue, the green channel drives the roughness and the blue channel drives the transmission.

This behavior can be key-framed. This can be used to animate materials per-object easily. Both cubes have the same material.

How-to animate it :


Trouble bending an arm at the elbow once subdivided

First you need to disable Limit selection to visible to see through the mesh, then select only the vertex of the elbow to bend the arm.


All your objects have invalid coordinates, and are positioned at infinity.
Don't know how that happened but the bottom line is Blender can't handle it so you can't see your objects.

You will probably have to manually place your objects again one by one, as no other methods seem to be working currently.

Go to the outliner
Set it to Current Scene
Select one of the objects from the list
Go to the 3D view
Open the properties tool shelf N key
Change the values for location from invalid values to 0,0,0or anything else that suits you

Changing for the parent of several objects seems to be enough though, for all others you will have to manually place them in the scene at correct positions again


How do you activate Text Editor in v2.78?

Problem solved. I was in Sensei format, a plugin created by the person who created Zbrush. It Changes the interface to something more appealing to nubies like me. I won't use it again because It makes it difficult to follow Tutorials. Text edit works as expected when Sensei is disabled.


How to disable scrollbars in node editor?

I don't think you can disable scrollbars.
But you can make them transparent.

Go to Preferences > Themes > User Interface > Scroll Bars
Set Item alpha value to 0
And Outline to some less intrusive color (it can't be made transparent)


Why doesn't emmisive material render in my camera?

First thing that comes to mind is that it might be camera clipping (basically that your 'render distance' is too short).


How to highlight intersection of meshes?

Yes, booleans can be used here. It should be noted that booleans can be rather glitchy in many cases. There are ways to mitigate them, but the methods I know of won't apply very well to the type of animation you're looking for.

Create a large cube that encompasses all of your objects. Then, apply two Intersect Boolean modifiers, one for each of the intersecting objects.

The first boolean will cutout the cube into something that resembles one of your objects (I say resembles simply due to the glitchy nature of booleans), and the second intersect will take the cube (that now is one of your objects), and cuts out whatever is not touching the second.

Here's a quick demo of that:


Ok I took a look at your file, You had to fix the rotation of two things.

Change the rotation for the particles to Global Z
Go back to your other layer and rotate the group as shown in the image
You had the pivot point at the top of all your buildings, So Blender assumes this is where the building should start. You need to select each building in edit mode, then select the bottom face, hit Shift + S and choose move cursor to selected. Hit tab to go back to object mode and on the left tool bar change pivot point to 3D cursor.

You need to do this to every building in the group.

Or you can just use the fixed blend file.


Render the same frame using multiple computers

Distributed rendering is not built into Blender. Instead, you can download this addon called CrowdRender and install it for Blender. The addon helps you do renderings on multiple machines in parallel. You can follow the steps described in this video to install the addon and use it for rendering. The addon already works with Blender 2.8 and can also use EEVEE for distributed rendering.


How to set visible render layers with Python?

My code may be awful (abeit easily readable), but I think the problem you have is this: it's impossible to turn all layers off. One must be turned on, so a loop to disable them all doesn't work. It seems that Blender is checking anytime you try to disable a layer whether it's the last man standing.

I simply turned it around by first switching the desired layers on and then disabling all others.

import bpy

visible = [0,4]
for b in visible:
    bpy.context.scene.layers[b] = 1

a  = 0
while a < 20:
    if a not in visible:
        bpy.context.scene.layers[a]= 0
    a += 1

edit: batFINGER reduced it to two lines, so give his comment an upvote (:

import bpy

visible = [3,6,9]
scene.layers = [l in visible for l in range(20)]

Creating the full list before assigning it is a smart move.


Object falls though other objects even when given the same physics

I've been having the same problem with objects falling through a cube surface even with a box collider. This post - Why is this passive rigid body allowing objects to pass through it? - has a really helpful comment from @satishgoda. If you go into the Scene tab in the Properties window, and increase the Steps per Second (I needed 300 steps) that should help prevent some of your smaller objects from falling through.


Render isn't showing my active viewport - just a texture

You need to enable Face Textures and Face Textures Alpha

And uncheck color as influence


How to create golf ball with dips in each dips?

When you click the faces and press I key and nothing happens reason

Individual options is off

To ON u have to press again I key

And with the faces selected S to Scale

A small preview of the ball


How to play multiple actions using action actuator?

Make sure your Current Frame on the timeline is set to the frame before the first animation. Usually 0. Then make sure the first animation starts at 1 and not 0.


To recreate this matcap try to use some Layer Weight nodes. Experiment with the Color Ramp node's modes and slider's placement also.

Here's my nodes setup. I basically added two Emission shaders- one with the white color and the other one with black color. Then used the Layer Weight (Facing) (with different Blend values) and Color Ramp (with different modes- Constant for the bright rim and B-Spline for the blurry interior of the sphere ) nodes.

Here's the test I've done using my low poly gerbil model. The matcap and the render result look almost the same. It is a matter of tweaking some things. If you want to play with the nodes to make the rendered matcap material look perfect here's the .blend:


The default Blender Exporter does not seem to be able to embed textures into Collada *.dae files (as of 2.79b).

It can however save textures alongside Collada files. To do that it has two sources of texture files.

Materials as texture source

See this video if you want to see it in action.

This is used when you select Materials in the Texture Options section of the Collada Export dialog.

The steps you need to make sure the texure is set, do the following:

Be sure that you are in Blender Render or Blender Game mode (you can switch back to another renderer after you set the texture)
1a. Select your object and go into the textures tab of the Properties Panel
make sure that you are editing the textures of the material
add at least one texture of type Image (you can add multiple textures and all will get saved)
set the image for the texture

UV Texture as texture source

See this video if you want to see it in action.

This is used when you select UV Textures in the Texture Options section of the Collada Export dialog.

The steps you need to make sure the texure is set, do the following:

Be sure that you are in Blender Render or Blender Game mode (you can switch back to another renderer after you set the texture)
Select your object and go into edit mode
open a UV/Image Editor panel and set the image you want to export as the texuture (you can switch back into object mode and this image will persist as the one that will be exported).


Blender Mesh to UE4: Correct normals but missing faces

You might have Normals facing in the right direction, but still get some missing faces in UE. Here's some solutions:

Try to Triangulate your Mesh in Blender (Add Modifier >> General >> Triangulate) and then Export it.
Apply all Transformations in Blender before exporting your model (in Object Mode, go to the Object >> Apply >> All Transforms)

By the way, you can also disable Backface Culling in Blender to be able to see your model without displaying Normals direction or color.

You can also activate double-sided Materials in Unreal Engine, but it will slightly reduce performance (depending upon the mesh itself).

Hope it helps!


Is there an addon to enable export of Blender object to an Objective-C header?

Did you try the latest version? There's one called objc_blend_2.62, which does not contain .faces anywhere in the code - so seems to be compatible with 2.63+ (and funnily not with 2.62!)

Link: objc_blend_2.62 @ Github


Add a Lattice and position it so that it encloses the object you want to deform.

Select the object to be deformed and add a Lattice Modifier to it.

On the modifier select the lattice that will be used.

Select the lattice, enter edit mode and change its shape by moving some vertices, the object will deform along with it.


Selecting a grease pencil object Blender 2.8

The approach I would suggest is to:

TAB into editmode
Lock the grease pencil layers you don't want to move (Click the pad lock in layers box)
Select all items in 3D view
Transform them as you would like.


Trackers are uniquely associated to the tracked shot.

In order to stabilize you need to select the clip you are using as source.


How to reopen the panel that shows when creating objects?

you can do this with F9.
But whenever you do something else in between - e.g. move another object - it is gone. Then you cannot call it again.


This is an old limitation, it seems.
To make it work, you need to place the material (only one) of the start/end caps as first material in the material slots of the arrayed object.

If the caps have two different materials, that won't work (only one is taken into account).


It is currently not possible to bake directly to an alpha channel as you mention.

https://blender.stackexchange.com/a/41904/28015

There are workarounds, though, like you could bake only an emission shader of the masking (in this case you already have the mask so there's no need for that), then make it the alpha channel in the compositor.

Here is the blend:

Just bake the texture, update the compositor, and finally, go the the viewer node in the uv editor.


How to edit normals so light is even all the way around for grass patches?

For this case you need to select "Directional" and "Parallel Normals". The vector from your object origin to the target object origin is set as the normal for each of the vertices.

For grass usage case I would recommend trying a normal that points straight up as this is unaffected by rotation around Blender Z / Unity Y axis. But please note that this will make the faces' shaded color identical so the only difference in color will come from albedo / diffuse texture.


Blender's "Right" View is actually a "Left" view? "Front" view is actually "Back"?

What is the right side of a house? Or a bed? Or a keyboard or TV? Does the text in a book go from the left side to the right side, or from the right side to the left side?

Even if there's a clear agreement on what the front of an object is, what is considered the left or right side depends on the type of object, so there's no way to have a convention in Blender that always works. What we consider the left side or right side depends on how we humans typically interact with the object.


Texture Painting issue - colour randomly showing on wrong faces

You need to:

Unwrap again, your islands are probably overlapping, choose the Smart UV Project option with a bit of Island Margin (0.03).
Put a bit of bleeding in the N panel > Tool > Options so that the paint correctly covers the islands.
Your image is currently 1024 pixels large, depending on what kind of shots you want to do it might be a bit too small, so maybe increase the size


Bake image from Mix Shader node output to show BSDF base color without light gradients

I found a way to do it. The only thing that I changed is setting the Emission parameter of the Principled BSDF shader to complete white (it was completely black).

Bake settings:

Result:

Downside:

The color of the texture created is no longer determined by the "Base Color", but by "Emission". So probably any other thing going into the base color parameter wouldn't end up on the texture I am affraid. But for my use case, this setup is giving me what I want.


Answer:
Thanks to Jerryno and Mentalist I understand now that the reason why the Cycles AO map is too bright is because unlike in Blender Render, materials in cycles don't affect AO bakes - rather a more physically correct lighting model is applied in cycles.

Other Solutions:
Metalist gave me the following info/solution (unfortunately, I haven't tried either because I don't know how to get them to work in a batch bake addon I'm using):
- Cycles materials can be used in Blender Render
- It's possible to create a cavity map using the "Pointiness" property on the geometry node for the mesh, and combine that result with the AO map.

I'm using an addon someone made a couple years ago to bake these AO (and normals), but it only works with cycles. I'll try to get help on converting it to work with Blender Render.  That, or I'll try to modify the addon to insert a semi transparent grey layer over the AO before it saves it out.


Strange lines appearing when render Anisotropic BSDF

Here is the final fixed result:

Shading

You need to click on the Tangent menu in the material settings and select a Tangent node. Make sure Radial is selected it its settings. Play around with the Axes: to figure out which one to use.

Gandalf3's image from here.

Modeling

Your mesh is covered in triangles (not good). From the .blend file that I downloaded, this was my process:

A twice to select everything.
Alt + J converts many tris to quads.
Ctrl + Tab, then 3 to enter Face Select Mode.
Alt +  RMB while hovering over one of the edges around the outside rim to select this face loop:

Ctrl + I to Invert Selection.
X > Faces to open the Delete menu and delete Faces.
Ctrl + Tab, then 1 to enter Vertex Select Mode.
Alt +  RMB while hovering over one of the edges in the topmost edge loop to select this edge loop:

F to create an N-Gon face.
Ctrl + I to Invert Selection.
F to create an N-Gon face.
Tab out of Edit Mode.

Here is the fixed .blend file:

P.S.

This is not included in the .blend file, but if you want less spotty anisotropy, you should use these settings in the Properties panel > Render tab.

They produce this result:


why doesn't texture paint show up on polygon materials?

Have you checked this video?

Here's a picture (tattoo being the texture you paint on):


Using python to set object shading to 'smooth'

Can set face to smooth in bmesh with

for f in bm.faces:
    f.smooth = True

Or in object mode

mesh = context.object.data
for f in mesh.polygons:
    f.use_smooth = True

The foreach set routines need a correctly sized value list for example

values = [True] * len(mesh.polygons)
mesh.polygons.foreach_set("use_smooth", values)

which is the equivalent of the for loop above.

Remember that when blender started to handle ngons (faces with more than 4 verts) it changed the mesh.faces collection was renamed to mesh.polygons.


How to select the all the edges of a loop cut?

You can hold Alt and then select an edge of the loop cut. The rest of the loop cut will automatically be selected.


Trouble with filling up faces, irregular shape

This can be caused by irregular vertex order.
Fill operation works well in such cases.

Select all vertices, Select > All (A)
Go Face > Fill, (Alt + F)
Join triangles into one shape through Vertex > New face, (F)


Is there a way to animate a camera along a curve at specific speed?

I'm not sure how you can do it with the standard tools, but I figured out a way using animation nodes that seems to work (someone might need to check my math). I basically created a subprogram that takes a Spline input and an object input(what will move along the spline). Then using some math, it takes the spline length, number of frames in the scene and a speed number and moves all the objects along their respective curves at that speed.

Maybe this will help you out, here's an example file.

edit: Thinking through this, you can probably replace the end frame value with just a float number set to some high number. That way this would keep the speed the same regardless of how long the scene is.


My liquid looks like tiny balls not like a liquid

While I can't say which version you use, I can be sure that you use a version of Blender that uses Mantaflow.
There are still some unknowns, so I try shine some light on the possibilities.

You use the Replay default setting of the "Domain-Cache"->Type:

With this you will not be able to scrub through the timeline as each frame needs to be simulated, BUT it's still possible to activate the Mesh option:

Beware that for this to show properly the domain-object must not be set to be displayed as "Bounds", else you would not see any form of geometry. With this setting you can run the simulation and should (slower then without the Mesh active) see the fluid shown as geometry. This is nice to get an idea and fine tune the simulation.
Should you have set the "Domain-Cache"->Type to any other of the available options like Modular, then you need to bake the simulation and by default the Mesh won't be baked along with it. That is to say, once the liquid is baked to the point you showed, all you need to do is activate the Mesh subpanel and in this panel will be a Bake Mesh button:

This button won't be there if in "Domain-Cache"-Type Replay mode. And the button will be greyed out if the simulation is not baked beforehand. Thus first bake the liquid, then you can bake the mesh. And different then in the 1st mentioned solution, you can not see the mesh simulated along with the blue particles in one go.
There is a final "Domain-Cache"-Type option All, which essentially on pressing the Bake All button:

This will simulate/bake all activated options in one fell swoop. While it may safe the separate baking and clicking, it may be most helpful for all set up(after trial and error and finetuning) simulation settings as a QoL option.

Happy Blending.

The pictures are taken from the 2.93 alpha version, BUT the differences to the latest stable version are not big enough and should not cause any confusion.


Civic art project: 5'H x 5'W 3D heart shape sculpture. Can Blender map a 12" grid on it? From photos?

Yes.

You will first have to model the heart which shouldn't be a problem considering you can get all the dimensions you need.
It may take a lot of tweaking to get precise measurements but you can get very close with little difficulty.

Blender has an option to change units. This includes Inches :D

Once you have created the model, look into UV unwrapping in Blender. There is plenty of tutorials on it. You can paint the object in Blender without exporting but I recommend exporting it and using a program like Gimp or Photoshop for better results. You could also print the UV and draw over it, then scan it back into the program.

You should be able to find tutorial videos on all the things you wish to do.

Some other helpful tools you may want to look into would include:

Grease pencil
Mirror Modifier

Helpfull Links:

Units in Blender
Blender for Beginners
UV Unwrapping

Though it won't make much of a difference when modelling, if you want to render a design picture, I recommend using cycles engine.

Good luck with your project and I hope I helped,

BFB


cycles transparency results in color loss when background is black?

Short answer

It won't work. Your technique has a fundamental problem that I'll explain below, but even if your technique was correct, some limitations of Blender's viewport will make impossible to produce the correct result.

Long Answer

Why the method you used wont work:

You say you used pre-rendered PNGs as source, and that's the problem.

PNGs use unassociated (often called "straight" alpha), which is inappropriate for compositing light effects.
The explanation is rather simple: A lighting effect, such as fire, electricity arcs, laser beams, etc.) is a purely emissive phenomenom, so itt's basically an addition (the light source adds luminosity but doesn't occlude any of the background).

When you use an unassociated alpha image (like your PNGs) every pixel with alpha > 0 will occlude the light coming from the background.
The phenomenom you're trying to reproduce shouldn't occlude any light from the background, so its alpha has to be 0.

But in unassociated alpha images, there is no RGB information where alpha is equal to zero, as that information is discarded by the alpha over operation for unassociated.
What you need is an associated image (often called "premultiplied), that lets you have RGB where alpha is equal to zero for this kind of effects, that need pixels that are luminous but don't occlude the background at all.

For that reason, PNG won't cut it.

The proper way to composite luminous effects:

If you use instead EXR images you'll be able to produce lighting effects that can be mixed with the alpha over operation as if they were a pure addition.
Just render your lighting effects on black, use a "set alpha" node to assign a 0 value (black) to the alpha channel and save as EXR, and you'll have some nice lighting effects ready to be composited.

Why it won't work anyway:

Blender's viewport, and to some extent cycles have some limitations regarding alpha manipulation.
The materials view does some funny things flipping between associated and unassociated alpha, which results in RGB with alpha zero being lost before it gets to your screen
So, even if you try to produce the right shader with cycles (which could work in the compositor), the material view will kill it.
Your best bet is cycles with a good GPU that can keep up the pace needed for realtime preview.

Since the phenomenom is purely emissive, you need an emit shader which is extremely fast to render, and the good news is that you need a few samples to get it rendered. Noise shouldn't be a problem (just use 8 for start resolution and one sample for preview, it will be fast and noise free).

The bad news is that cycles has some problems producing a proper output from a shader constructed with an alpha-driven mix where pixels have to be luminous, so you can connect the nodes in cycles to produce a luminous premultiplied image, but it won't render correctly.

But wait, there's hope! :-)

Not everything is lost: If your ligthing effects are purely emissive and you don't need any occlusion (which means, all your alpha will be zero), you can create the effect with cycles.

First you have to create an emission shader using the ligthing effects rendered on black background as texture, then you need to ADD that shader to a transparent shader using the add shader node.
The output will work in the cycles render view and it will be fast.

It won't work in the materials view, though. It will render white.


How to smooth out the slope between two fragments?

With your mesh selected go in to sculpt mode.

Choose the Smooth brush by pressing S, then LMB  and drag over the places you want smoothed.

If you do not want to use sculpt mode.

In edit mode, select all of the vertices, by pressing A A. Then click on the button on the tool shelf, on the Tools tab under Deform: called Smooth Vertex. You can adjust the number of iterations the smoothing runs in the bottom of the tool shelf, or by pressing F6.


As his left foot is correctly rigged you can check how it works. Notice that there are actually 2 bones overlaying on each foot, they are called Toes Control (R and L) and Toes (R and L). So to make it simpler, switch to Pose mode, hide the bones called Toes Control (R and L), then switch your mesh to Weight Paint mode and check how Toes (R and L) influence your mesh. You can see that Toes.R, contrary to Toes.L, has no influence. So begin to paint the area that is supposed to be influenced by this bone, exactly like Toes.L influence the left foot. You're good.


You can get the icon value from the UILayout classmethod icon

Example using the simple panel template.

import bpy

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

        obj = context.object
        mat = obj.active_material
        layout.label(mat.name, icon_value = layout.icon(mat))

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

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

if __name__ == "__main__":
    register()


How do I re-hide the bar with "View, Tool, Item"?

It's named Sidebar.
There is three ways to hide it:

Drag the corner of sidebar to the right:

View3D > Menu > View > Sidebar (visible if checked):

Shortcut: N, as mentioned on previous screenshot.


Boolean Modifier Issues (Engraving text on to a face)

You actually did what you wanted in the second picture, the old Text mesh is only still visible... you could delete it or hide it to see the results. Further notes on general good practice: After following Hikariztw's suggestion to join the text objects together first, which makes life way easier, you could try changing the solver to "Carve"... (in the modifier) takes a bit longer but is more accurate and less buggy most of the time. Also you could try to recalculate normals in edit mode for both objects (ctrl+N) –


Glass bottle's inside remains opaque in blender render bottle

Make sure the Depth is set high enough in Material > Transparency:

Note that setting it to very high values will increase rendertime significantly (note the rendertime recorded in the top left of the gif), so try and use as low a value as you can get away with.


Unable to see rendered View even after adding HDRI and exr files

Since the World Output node doesn't have a red header and the World Properties show that a background node is connected, you have another World Output that is active. You will have to remove the duplicate output in the node editor, that is likely somewhere outside the visible area. All nodes can be brought into the view through View > View All (Home or pos1).

The proper node setup for HDRIs is shown in the following image:


How to cut a hole through both sides of a cube?

After invoking the Knife Tool the status info shows:

For each cut:

Press C to align the cuts
Press Z to cut through

First cut the vertical then the horizontal edges.

After removing the faces you would need to add more edges (highlighted vertices) or use the Window creator and place a completed window at this position.


Using shrinkwrap doesn't wrap the object correctly

If your logo has only one face, it can't bend/shrinkwrap on a curved surface. Add a subdivision modifier to the logo so it creates more geometry, allowing it to bend. I would also try adding the shrinkwrap to the logo instead of the lattice.


Blender only has 1 unitless unit: the Blender Unit.
You can't create any others, but that doesn't matter, since it does exactly what you want.

At first your BU equals 5mm. Enter 0.005 in the Unit Scale checkbox.

Switching between metric and None will you either Dimensions of (1, 5, 3) or (5mm, 25mm, 15mm).

Changing the translating to 1 BU = 6mm seems pretty straightforward. Simply entering the new value 0.006 produces dimensions of (6mm, 30mm 18mm).


(Blender 2.8) Smoke not showing in Physics Properties

It appears that the smoke simulation is now under fluid for 2.82


Reverse armature deformation on vertex in python

Answering own question: Ended up by applying deformations as displacement with custom texture AFTER armature… shapekey is essentially just a displacement for verts, after all, and making this displacement after armature make more sense. and easier to implement (just baking verts shift into packed image)


.fbx files do not transfer textures, so you need to manually apply them in unity. However, the unwrapping should transfer over, so all you need to do is apply the textures manually in Unity.


Short answer, no, Freestyle doesn't currently support detecting face intersections so what you want to achieve is basically impossible to do at this time, as far as I know.
There has to actually exist an edge there so Blender can detect the intersection and place a Freestyle stroke where it belongs.
Ideally you would build your model accordingly, so that there would be no intersections and your model is correctly shaped with no "inside" faces.
Otherwise you may try to use boolean operations through the Boolean Modifier and automatically intersect your objects and let Blender create said edges.
Have in mind that boolean operations have limitations, and will only work on closed, manifold meshes with no duplicate vertex or edges, consistent normals and non coplanar faces. Failing to do so will often result in unsuccessful operations.
Also boolean operations only work on two objects at a time, so if you have lots and lots of objects it will quickly become unpractical since you would have to preform Boolean operations for every possible combination of pairs of objects.
You will also end up with bad topology all over your model.
Search this site for Boolean, there's about one question of those every day. You will encounter most often found problems, caveats and solutions for them.


Bones parent-child relationship on different axis

Try a transformation constraint on bones 2 and 3.  Transformation constraints take the transformation of one bone and use it to apply some arbitrary transformation to a different bone.  They're sort a poor man's driver.  (This is also something you could easily do with drivers.  Plenty of other ways too.)

Let's say you want bone B to move 1 unit in the positive X local axis when you move bone A 1 unit in its positive Y local axis.  Create a transformation constraint on bone B.  You want to affect position on both bones, so use "loc" (location) for both bones.  Map Y to X.  Set it to use local space for both bones.  Finally, enter a range of values for input and output; in this case, use 0 to 1 for the source Y and 0 to 1 for the destination X.

For the other side, it's the same constraint, except you want it moving in the opposite direction-- so map the destination to 0 to -1 in the X instead.


Locked Y axis rotation is also rotating on Z

From the image it looks like the rotation is normal but your handle is not centered on the mug and that's causing it to look warped.


Just to illustrate Moonboots' comment with a gif :).


How can I select only the inside of the mesh?

Try temporarily disabling the subdivision surface modifier and see if that makes it any easier.


There are utility functions to convert 2d region coordinates to 3d:

bpy_extras.view3d_utils

There's also a method to cast a ray in the scene:

Scene.ray_cast

... but it might not work with orthographic view.


pivot object over two different axes by pulling on its edges

If you're willing to rotate the plane, which in turn makes the cylinders go up and down, you can do it this way. (I'm using blender 2.79)

Select a cylinder, then the Plane.
Go to Edit mode
Select one vertex of the nearest corner to that cylinder, then go to Mesh/Vertices/Make vertex parent, and click on the "confirm" dialogue box that pops up.
Come back into Object mode and repeat 1 - 3 for the other 3 corners.
Give each cylinder a Limit Location Constraint.  Copy each cylinders current X and Y position and paste them into the first two fields of Minimum and Maximum values in the constraint.  That is, limit the location to exactly where they are on the X and Y axes but leave them free to move on the Z axis.
Rotate the plane on the X or Y axis and the cylinders will move (vertically only) accordingly.


How to consistently texture one object with two materials and two colors?

you can mix shader to add two principled bsdf and use linear and noise like fac:


Computing and animating mesh deformations

Having two meshes with the same topology (The meshes must have the same number of vertices for this to work) you can easily use one mesh to define a shape key of the second mesh.

First select the mesh that you wish to be the shape key, then shift-select the target mesh. In the mesh properties click the little down arrow next to the Shape Keys list and select 'Join as Shapes'

You can have multiple meshes that each get applied as shape keys in the one step, each separate object will create it's own shape key.

You may also wish to copy a shape key from one object to another with the Transfer Shape Key.


Organizing with states

You can use the states of the build-in state machine to group your bricks.

This allows to quickly show/hide/switch logical groups. You can do that by selecting/deselecting states in the visible-state-bar.

Requirements

Make sure all states with logic are enabled in the initial-state-bar.

Example

This way you can group this logic:

into movement logic:

using logic by keyboard

and using logic by mouse

Hints

You do not need to use the state machine operations (state
switching).
You can select multiple states at the same time by
holding  when selecting/deselecting a state.
If you need more than the 30 available states I think it is time to review your design. Most-likely this object simply does too much. It would be better to spread the logic over multiple objects.


Render Layers node doesn't have denoise sockets

In the View Layer panel > Passes > Data, you need to activate the Denoising Data option.


Why the cloth penetrates collision object?

Since there isn't a .blend file, it's going to be challenging for us to properly diagnose your solution, since we won't be able to reproduce your setup.

That being said, I can see one thing that might help. The "quality" counter that you show in your screenshots is at 1. When I simulate cloth, I often increase the quality steps. For example, in Blender 2.82a, if I make a plane and apply the cloth modifier, I usually use these quality steps:

I increased the Cloth -> Quality Steps from the default value of 5 to 10. Furthermore, I increased the Collisions -> Quality from the default value of 2 to 5, and turned on Collisions -> Self-Collisions. Since your screenshots show quality values of 1, you might want to significantly increase that number. I would recommend looking at some Blender 2.7x videos that use cloth, and pay close attention to the quality steps value that they use. For example, this video seems to use values of 5 for the quality steps.

As an aside, consider using Blender 2.8. The more recent versions of Blender have significant improvements to the cloth simulator. For example, consider this blog post or the release notes Wiki, which for example, say that 2.83 has improvements with cloth collisions.


Scripting: low level join meshes / elements (hopefully with bmesh)?

The best solution I found so far is using the bmesh.from_mesh( mesh ) method.
Apparently, if you call this method more than once, it will add the 2nd mesh to the first, thus effectively joining them:

import bpy, bmesh

bm = bmesh.new()
bm.from_mesh( mesh1 ) # Add first mesh
bm.from_mesh( mesh2 ) # Add 2nd mesh

However, this does not really help with adding individual components from another mesh or bmesh in a direct manner.


First of all, always Save All Images in Slots tab (Texture Paint mode).

Secondly, Save or Pack as PNG texture in UV Image Editor before closing Blender.

Images used in blender must exist as a file somewhere on the computer (or network). Saving the images will do that.

By default blender reads the images used from the place where they are saved. To make the .blend file self contained, with the images included within the project file, then pack the images


Issue with Cycles rendering regarding my GPU

The "(Display)" in system preferences means that GPU will work to process all elements in viewport, not on rendering. You just make it available. If you really wanna have GPU rendering acceleration, you have to select in Render section


From what I can tell is you just have to change the Radius Unit to Scene for the scale to stay consistent with the model. Changing it to View will scale the brush according to the user view port.


Assuming you just want to display a bounding box around or instead of each object, you can do this with Draw types.

Drawing a bounding box instead of the object:

You could set Viewport shading to Bounding box to draw the bounds of each object:

A comparison between Solid and Bounding box:

To do this for one object only, you can set this in Properties > Object Display > Maximum draw type:

Drawing a bounding box around the object:

This can be done by enabling Bounds with the Maximum draw type still higher than Bounds:

This looks like this:

You could do this for many objects by:

Select the objects for which you want to enable Bounding box
Enable Bounds in Object > Display
Right click on the Bounds option and select Copy to selected: