text:
How to copy and paste pixels in an image
Consider the image texture below:

Is it possible to select an area of the image and copy and paste it?
For instance:

There isn't a way to do this in the Image Editor as is done in the dedicated image editors outside of Blender. In Photoshop, you would use a magic wand or a marquee tool to make a selection and then duplicate to a new layer and move it about.
Blender is first concerned with geometry and drawing the mesh and then including the pixels of the texture on that mesh, so anything pixel related has to be solved through geometry.
If you bring your image texture into the 3d view as an Image Plane with shadeless or emission shader options, you can set up an orthographic camera to the same pixels as your image and adjust the Orthographic scale until the full image is in view. Then you can do a really neat trick of making a duplicate of your image plane and subdivide it such that you can select the faces that make up the part of the texture you want to duplicate and delete the remainder of the faces. You can then move it around in Object mode and place the duplicate where you want, as well as use an Array Modifier on it or any other thing you can imagine.
Your camera can then render to a new image that you can save as an iteration of that original texture.
I built a workflow around this topic and got help setting up an addon to do it called Draw2Paint. The idea to eventually improve the Image Editor to do this as other editors do is already posted on RightClickSelect dot com, but if you want to look for it and give it and upvote maybe later when the Devs are working on image editing and painting they will see the enthusiasm for it.
edit: I stripped out the Image2CanvasPlus into its own addon so you can quickly set up from the image editor to the 3d view with matching camera. https://github.com/artistCDMJ/Image2CanvasPlus/tree/main

To add to Craig's answer, for your particular case, a workaround would be to use the Clone brush as Stencil in Texture Paint mode in the 3D view (in Orthographic mode) and select a copy of your image as texture, but the easiest solution is to use an image editor like Krita.


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Is there a way to render overlapping geometry as different passes/layers?
I want to be able to take a scene and render the geometry as different layers based on their overlapping depth (from the view); ex: by using an index.
For a sphere, the index 1 would be rendering the front surface and index 2 the back surface. Of course, the goal is to be able to render any kind of scene.
I don't know how this could be done (if it can), EEVEE is probably too limited by the depth buffer workflow; Cycles may have features I'm not aware of which could lead to a solution.
My use case is external deferred compositing of overlapping objects.

I found a way with Cycles for my use case by using the Transparent Depth of the Light Path node.
A transparent shader is mixed with the original shader based on the pass index required. If the transparent depth is equal to the pass index, then it should use the original shader, otherwise it should be transparent.
Node setup:

Sphere 0-1 indexes:

Suzanne 0-3 indexes:

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Custom Renderer as an Add-on
I have been writing a custom raytracing renderer in C++ and I would like to natively integrate it with Blender 2.8 as a custom renderer. I know that this is possible, as I have seen many projects (for example, SORT) do this. However, I am completely new to Blender plugin development and am at a loss for how to even approach writing such a plugin.
I vaguely know that I'll need to re-write all of the material nodes and that I'll need to somehow pipe data back and forth between Blender and my renderer. Other than this, I am completely lost.
The closest threads that I can find regarding this topic are this and this, neither of which is particularly relevant to what I'm trying to accomplish as far as I can tell.
Could someone push me in the right direction? If there is a minimal example then I could probably take it from there.

Hello world engine example in the API docs might be a good start: https://docs.blender.org/api/current/bpy.types.RenderEngine.html If you'd like to have custom nodes, have a look into luxcore add-on: https://github.com/LuxCoreRender/BlendLuxCore

@brockmann this I can work with, thanks!

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Get edge position in uv layout
I want to get the per-edge position in uv mask,The position here refers to the x, y coordinates(in image coordinate system) of a series of pixels forming an edge,for example:
Assume we get a unwarped uv map like below:

That uv map has 31378 edges and the resolution is 500*500,The output of what I want is:
A list that length is 31378, assume its called edge_index_500,each element of edge_index_500 is combined by two array,array 1 store x coordinate of the serials of pixels that form a edge,where array 2 store y coordinate in correspondence.
How to implement that with python script?

Hello, could you elaborate on what you tried and didn't work ?

Actually I am quiet new to blender python API ... I even do not know the basic procedure of how blender python script running...


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How do I connect these meshes correctly?
I'm trying to model a gun and its requiring me to connect the meshes. I'm using blender 2.83 beta.

You should begin with the circular shape because it's the most convenient to do, then make a series of extrusions.

If you're looking for clean topology, these are some ways to connect it.


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BLI_assert failed edge_hash
I use the following python script that imports a stl, modifies it and exports the modified stl in a Docker container running Ubuntu 18.04 and Blender 2.79:
import bpy
import os
import sys

if len(sys.argv) < 8:
    print("Usage: blender --background [optional args here, for example -noaudio] --python stl2safety_distance.py -- safety_distance_in_m input_path/file_name output_path/file_name")
else:
    input_file = sys.argv[len(sys.argv) - 2] + ".stl"
    if os.path.isfile(input_file):
        bpy.ops.object.select_all(action='SELECT')
        bpy.ops.object.delete()
        bpy.ops.import_mesh.stl(filepath=input_file)
        bpy.ops.object.editmode_toggle()
        bpy.ops.mesh.extrude_region_shrink_fatten(TRANSFORM_OT_shrink_fatten={"value":-1.0 * float(sys.argv[len(sys.argv) - 3])})
        bpy.ops.export_mesh.stl(filepath=sys.argv[len(sys.argv) - 1] + ".stl", ascii=True)
    else:
        print("Input file does no exist: {}".format(input_file))
        raise

The stl is exported as expected, however I get the following output (even multiple times) in my terminal:
blender(BLI_system_backtrace+0x33) [0x56400a4a7fb3]
 blender(BLI_edgehash_lookup+0xfd) [0x56400a46591d]
 blender(BKE_mesh_calc_edges+0x226) [0x56400a208cf6]
 blender(ED_mesh_update+0x57) [0x564009caaa27]
 blender(RNA_function_call+0x12) [0x56400a3174a2]
 blender(+0x14c4fbd) [0x564009e73fbd]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyObject_FastCallKeywords+0xd3) [0x7f20086c1043]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0x2f33) [0x7f20084bcd53]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(+0x794d3) [0x7f20084c44d3]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0x7b95) [0x7f20084c19b5]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(+0x794d3) [0x7f20084c44d3]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0x7b95) [0x7f20084c19b5]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalCodeWithName+0x996) [0x7f20085e91e6]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyFunction_FastCallDict+0xae) [0x7f20086c030e]
 blender(+0x14c5907) [0x564009e74907]
 blender(+0x1a6ffa6) [0x56400a41efa6]
 blender(+0x109c79e) [0x564009a4b79e]
 blender(WM_operator_call_py+0x6b) [0x564009a4c11b]
 blender(+0x14d0f5a) [0x564009e7ff5a]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyMethodDef_RawFastCallKeywords+0x2f9) [0x7f20086bfcc9]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyCFunction_FastCallKeywords+0x25) [0x7f20086c0a05]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0x8bde) [0x7f20084c29fe]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalCodeWithName+0x996) [0x7f20085e91e6]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyFunction_FastCallDict+0x1c3) [0x7f20086c0423]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyObject_Call_Prepend+0xcd) [0x7f20086c320d]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(+0x215c35) [0x7f2008660c35]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyObject_FastCallKeywords+0xd3) [0x7f20086c1043]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalFrameDefault+0x2f33) [0x7f20084bcd53]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(_PyEval_EvalCodeWithName+0x996) [0x7f20085e91e6]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(PyEval_EvalCodeEx+0x3e) [0x7f20085e946e]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(PyEval_EvalCode+0x1b) [0x7f20085ea23b]
 /usr/lib/x86_64-linux-gnu/libpython3.7m.so.1.0(PyRun_FileExFlags+0xb2) [0x7f20085b7e52]
 blender(+0x14bb515) [0x564009e6a515]
 blender(+0x1092c82) [0x564009a41c82]
 blender(BLI_argsParse+0xd6) [0x56400a4542e6]
 blender(main+0x264) [0x564009a093e4]
 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7f20035b909b]
 blender(_start+0x2a) [0x564009a405ca]
 BLI_assert failed: /build/blender-X0i0N1/blender-2.79.b+dfsg0/source/blender/blenlib/intern/edgehash.c:95, edgehash_bucket_index(), at 'v0 < v1'

Do you have any idea what might cause this BLI_assert? What does edgehash_bucket_index(), at 'v0 < v1' mean?
Any help is highly appreciated :)

Based on old reports, the input file could be corrupted or it's a bug in that version of Blender. You could check if a newer version of Blender doesn't have this issue.

Thanks a lot. Indeed this is bug in Blender v2.79. After upgrading to v2.82 the output disappeared.


text:
Weird deformation with fingers (automatic weights)
Hello i was rigging an arm for my game and there's this bug if i rotate my fingers this deformation happens, How can i fix this? This is using automatic weights
I tried using other types but it didn't work, I tried redoing the rig but still same bug.
What i'm trying to do is not to make the hand move but the fingers, The fingers should move the fingers, not the hand.
https://i.sstatic.net/eXSjV.jpg

hard to help, please share your file: https://blend-exchange.giantcowfilms.com/

The rigging is bad: Select the armature, shift select the object, switch to Weight Paint mode, then select each bone, you’ll see what part of the mesh they affect. You can see that the first thumb phalanx affects the palm, which is not supposed to do. Some other phalanx also affect the palm.

So you need to:

Create a bone for the palm itself
Parent this bone to the last arm bone (Keep Offset mode).
Parent each first phalanx to this bone (Keep Offset mode).

In Weight Paint mode, paint the influence of the palm bone (enable the 2D Falloff option to paint through the mesh).

Also remove all the unnecessary influences.

Now it works fine (don't know why your arm has 3 bones though).

thank you so much!


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Blender 2.93 - Second Window always focuses
I use dual monitors with Blender, and the newest update (2.93), doesn't let me keep other windows on top while blender is active. If I click on my primary Blender window, it moves the second window to the front as well, and it's not really ideal for when I'm looking at reference on the other window. Is there a way to turn this off? Where are the settings for it?
This wasn't an issue in Blender 2.92, since the the only window that would focus was the one you clicked on.

Look here: https://blenderartists.org/t/render-window-is-now-forced-to-be-on-top-of-main-window/1309100


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How do I turn on path influence while keeping the object's position?
When I go to turn on the influence a path has on an object, the object moves very far away. How do I make it such that the object will stay in the same global position while I turn on the path influence?
I need to move a path to the object, have the object move along the path, then the path needs to move back away. I know how to animate the influence the path has, I just need to be able to make the object stay in place while doing so.

See Blend file below  (Vers 2.77a)

I've done this using an empty to follow the path and the cube simply being parented to the empty at the path's starting frame by using a "Child-of" constraint.  The constraint takes over at the intercept frame and releases the cube again once the path trek is complete.  The path is moved away, leaving the cube behind.
There's a bit of fiddly stuff with the Child-of constraint and that's been outlined below.  My thanks to whoever put this together months back, explaining exactly how to remove the 'Child-of' cleanly and without the model jumping back to it's starting point.
-=================-
The Itty Gritty -
Set up the path first, using an empty to follow the path.  Get that working right.   In the Dope sheet, slide it's valuation keyframes forward to the frame where the cube is to enter or intercept the path.  The path's empty will then delay it's start until that frame.
Animate the path to intercept the cube a frame or more before the path empty is due to move.
The cube must now be parented to the path's empty using a "Child-of" constraint.
Take the timeline cursor to frame 1 and set the constraint's influence slider to zero.  Keyframe that.
Take the timeline cursor to the frame before the path empty is to move and keyframe the constraint's influence slider again. (still at zero)
At the next frame give the influence slider a value of 1 (100%) and keyframe that.
The cube may want to jump when this is entered.  Simply click the 'Set Inverse' button in the constraint.  The cube should return to where it was and will then be parented to the empty.
The empty will follow the path and take the cube with it
-===========-
At the frame where the path-following stops, keyframe the constraint's influence again. (value of 1) and also keyframe the cube's Location & Rotation.
Move 1 frame forward
Select the cube and open the Object menu below.  choose "Apply -> Visual Transform", do not move the timeline cursor!
Keyframe the Child Of Constraint's influence to 0%
Keyframe the cube again. (Location & Rotation)
You can now move the timeline.  The cube should again be free of constraint.  i.e. no longer parented to the path's empty.
The path can now be animated away, leaving the cube behind.


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How do I make an object begin following a path, but only after a certain point?
I need to animate a ball moving up and through the inside of a robot. I have a path that is a child of the robot object, so it moves with the robot. The idea is that the robot will move up to where a ball is, then once it gets there, the ball can move on the path, and stop a certain point, then the robot will go back away and the ball will maintain it's new global position.
The ball needs to start on the ground, the robot (which has the path as a child) moves to the ball, the ball then follows the path for a little ways, then stops. The robot then backs away, but the ball needs to maintain the position it had before the robot backed away.
I need to be able to turn off the influence the path has on the ball object at certain times, and turn it on at others. How do I do this?

Are you sure it's a good idea to parent the path to the robot? Basically what you want is the robot to grab and drop the ball? In that case use the Child Of constraint, maybe follow a tuto like this one: https://www.youtube.com/watch?v=aCvZqdHSYmg&spfreload=1

If you use Follow Path object constraint(Ctrl+p -> Path constraint with object and path selected path being last/active), you have a property of Influence that you can animate(set keyframes to with i while hovering mouse over it) in order for it to start having influence only at some point.


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Lost of project
I am trying to design a full 3D human body design. Today, I clicked on the camera button by curiousity but I think I lost the project.
This is what I achieved so far and I think I lost it.

I am new on blender and I really need your help this is what the project shows me when Iopen the saved project.

Please how can I get my project back. Any Idea?
Thank you  in advance.

On your current screen you have both the timeline and UV editor open. I assume you want the 3D viewer, so click on the bottom left button, with the icon of a little landscape. From here you can select editor you want, which is 3D view to get back to your model.

You are clearly very new to blender. I'd recommend moving onto the new version 2.82 which is much clearer and a less cluttered interface.

Thank you so much for your answer. It helps.


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Why my render doesnt reflect the color and properties of my shaders applied to the object?

The bronze effect is with the help of quixel textures and there is an HDR image in the background. How do I preserve those effects and bronze texture in a render animation or image?
I'm using the shader mode and I have checked the transparency also, in the film section of the render properties. For the Render, I´m using Cycles with CPU toggled on.

https://blender.stackexchange.com/questions/170533/which-mode-should-i-trust-for-lighting

So basically I cannot render the HDRI effects on the Drill bit? Because I don't want the preview mode, I want that this can be reflected on my final render or animation.

You can, you just have to set it up beforehand, Material Preview Mode doesn't necessarily represent final render. You can also render the viewport

Ok so it rendered the animation on material preview, but it didn't worked with the viewport shading: rendered. Like, makes my object invisible and moving, of course, any idea of what is going on? Thank you for the help :)


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Cannot select vertices of any object In blender, while in edit mode and using Archipack
So, Im making a course on Archipack (add on for architecture and building houses), and Im trying to select vertices then put the cursor on the selection position, and therefore I can add the window through the Archipack menu.
It enables me to select the windows on the Outliner menu, but when I enter edit mode and enable vertex mode, I cannot select any vertices even though there are 2 vertices selected by default, inclusive putting lasso tool or any other type of selection. I've restarted blender twice, and I don't know what kind of problem it may be, considering my mouse is a brand new one (HP) and I also checked its battery.
Please don't say me that my file is corrupted or something...
Thanks in advance for your help,

I updated my Blender to 2.91 and I already can select the vertices again, but if you manage to give another solution I have 2.90 as well so another person can find an answer to this problem.


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How can I subdivide this if I cannot use the loop tool cut?

So I want to subdivide, then use LoopTools and finally circularize that section to include that piece of the model in the object (the one in blue on he photo and previously modeled), but I can't. Please, any suggestions?
Thanks in advance to everyone who took the time for reading this!

You can't use the Loop tool because you've got NGons. You can use the Knife Tool instead.

Ty so much, but how? There is a square in every side, so it applies the 4 vertex thing

Remember to press Z when cutting with the knife tool to cut through both sides.

At least one of your polygon has more that 4 vertices ; this one has 5 vertices:

You can't use the Loop tool because you've got NGons (more than 4 vertices). You can use the Knife Tool instead.

Omg TY, I´m very distracted, there is indeed 5 vertices. God bless you or whatever you believe in!


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Is there a way to simulate the drilling process in blender without using FEA (finite element analysis)?
so I'm trying to create a commercial AD for a drill bit made of tungsten carbide, this drill bit is made for cutting concrete walls especially when it comes to passing through rebars. I've made some research and find about LS-DYNA which is used in engineering in order to simulate problems and process, that involves physics and a lot of concepts. The thing is I've done a simulation and it takes 13 DAYS to only simulate 10 seconds of the drilling process in LS-DYNA.
Can someone enlighten me about how to simulate without burning my computer?

https://blender.stackexchange.com/questions/79445/using-boolean-modifiers-and-shape-keys-in-animation/79449

Yes, thanks for the help, I used live boolean modifiers to achieve that goal.

Using mesh master tools add-on you can achieve the drilling process simulation without burning your PC. Thanks to Duarte Darrajota Ramos and Emir, for the ideas.


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Why particles are not rendering in Eevee engine even using the instancing object in Render option?
So, I've made an animation of a drillbit cutting through a concrete wall, and I want to animate the chipset (dust) so I've used the vertex groups to make the particles system to emit from the head of the drill bit, I've assigned it to the vertex group which is named 'Group', applied rotation to the particles and using Particle System> Render As Object an Icosphere to render as the particles emit, the Icosphere has a concrete procedural material as well .
But nothing appears, if use the render mode at 'Halo', renders in the viewport but doesn't appear on the AVI output (viewport render animation).
I use viewport from render because I don´t have a great GPU, and use 16 samples as well. Thanks in advance for your help.

please provide blend file so we can check it out

Maybe the Render > Scale value of 0.050 is too small and the particles are so tiny that you can't see them?


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How can I create a SDS Cross Point Drillbit?
I don´t know how to approximate to the creation of this object, maybe I have to use sculpting plus modeling in order to achieve this, it´s not as easy as making the form of the object and then using the screw modifier to make a spiral, I used other things like archimedean and helix forms and then manually adjusting, but I think there is an easier path for making this.
I need like an starting point, maybe another way to create this, a good starting point.
Thanks in advance

what part are you struggling with? You can certainly get the screw part with the Screw modifier...

The only way to approximate this object with high fidelity is that you use the twist option of the simple deform modifier and put it to 720 degrees, in the section of the simple deform modifier, then from that point, you can recreate the double flute. If you are using 3DSMax, there is a twist modifier as well.
Don't forget to flip normal and then extrude them to make the flutes, the cross it's a little bit tricky but then it will take form step by step.


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Texture only one side of face
So I have a vase which I have textured.

But as you can see, both the outside and the inside have the same texture, however, what I want is the outside to have the flower pattern, and the inside to have a solid color. Is there any way to do that?
PS: I am making this model for a game, not for render.

In 3D view, Tab into Edit Mode. Set your selection mode to face select (mode toggle is in the upper left hand corner of the 3D viewport). Select the inside faces of the vase. Press P to separate then select Separate by Selection from the pop-up menu. It should be the default option. If so you can just left click after pressing P. Tab into Object Mode, select the separated inner surfaces and apply a new material to them.

You can apply different materials to different parts of an object, you shouldn't have to separate into a another mesh just for that.

Agreed, simply go into edit mode, select all the inside faces, in the material tab hit the + button and add a new material. Pick a color and hit apply while the faces are still selected.

I did not know that different materials could be applied in edit mode. Good to know. It's great to be a part of this community and always learning.


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Blender normals problem
So, I have an object to which I preformed a boolean operation. The problem is that by doing that, some of the normals on the object are facing the wrong direction:

Now, the object looks fine in blender, but when exported to Unity, since faces cannot be double-sided, they appear facing the wrong direction and appear invisible:

So I tried recalculating the normals to see if it would fix that problem, which it did, but it created another one:
Now the object looks very weird and lit wrong, and I have no clue what's wrong. I've recalculated the normals again, I've flipped only the normals in the door part, but nothing seems to fix it. If someone can help I'd be very grateful.

Well don't I feel stupid now... Thanks a lot, I'm a bit of a noob as you can see and I had no idea.

Hello :). Please mark the asnwer as accepted ✓, for others with a similar problem. Thanks.

The edges of the door arc aren't marked sharp like the other edges that are colored light blue. You can either mark these edges as well (select the edges then Ctrl+E > Mark Sharp) or set the shading to flat for the entire mesh.


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Image Sequence Shows Last Frame Past When Sequence Ends
I am compositing a smoke effect that didn't render (I had forgotten to include the smoke cache on the computer I was using to render). The whole sequence is 400 frames, I only need the smoke to run to 291 (the end of the sequence) after which I included the smoke in the original render.
To composite using Blenders compositor, I have the image sequence in the compositor and my fix works perfectly - except that after the end of the smoke sequence the last image of the smoke image sequence lingers on in the render - it should be blank.

The smoke "fix" ends at frame 291, and my screen grab is from 364 so you can clearly see that frame 291 is showing in the composite. There MUST be a simple way of fixing this. otherwise how would one put a simple overlay into the composite when necessary? I guess One solution would be to make a completely blank frame at 292 for that sequence.

Sure, if you don't want any overlay after frame 291, just don't overlay it anymore...? I don't understand what's the problem here. And as the question reads, it sounds as if the original render is okay after 291, so why re-render anything past 291 anyway? Either it is a bit misunderstandable what the issue is, or there is no real issue...?

I wondered if this would be a hard problem to communicate...the problem is, the final frame of overlay (the smoke) shows past its final frame. Instead of the image disappearing is it would in other compositors, it carries on. So frame 291 of that overlay is showing in frames 292, 293, 294 and so on. You can see the effect of this in the image above.

Yes, I understood that it's showing on the other frames. My question is, you make it overlay the other frames. Why don't you just stop overlaying it after frame 291? Please clarify how you have set it up that it seems impossible to you to simply not overlay it anymore?

Well how do you do that? If you add an image sequence node in the compositor, and the sequence overlays until 291, the last frame continues to be displayed. I guess one way would be to render out from the compositor to 291, mute the image sequence node and then continue rendering. Or, in the end I made a blank alpha image at 292 for that sequence. These are workarounds though. How do you make it not overlay when you get to 292?

The compositor is not a sequencer. Every image texture/sequence node if not muted or set to a factor 0 if mixed in with a color mix node will output something - and if there is nothing else to display after frame 291 it will show the last frame. Like image texture nodes elsewhere, for example the shader editor, if you load an image, it cannot "not" output the image, you have to mute it or change the mix. If you want a sequence to only last for a certain frame range without muting, use the Video Sequence Editor. There an image sequence strip will only show until the strip ends.


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Animation of Selected Object Not Show Showing in Editors
I have been having a problem recently (could it be 2.83?) whereby the animations are not showing the selected armature.
Initially they do show but as I work more and more, the editor will only show the selected bones, until finally none of them will show. Also if the NLA is used at all, it's very difficult to get the dope sheet and the graph editor to show again. Usually by switching to and from various bone groups after selecting the animation icon in the Scene Collection.
How do you get the graph editor back after using the NLA? I have attached the Blend file and a screen shot showing the selected elements resolutely refusing to show in the dope sheet. My work around atm is to export an FBX and reimport it into a fresh Blend file.
Blend file not showing animation

I don't see any problem with your file but I'm not playing it with the latest version.
For the moment the armature is playing the animation that you've pushed down into the NLA editor. To see or edit this action you can select the strip and press Tab, the strip will turn green and the keyframes will be displayed in the Dope Sheet.

If you want to load any other action, switch the Dope Sheet to its Action Editor mode and choose whatever action you want in the dropdown menu (now the Dope Sheet will play over the NLA, to come back to the NLA actions you'll need to close the actions you've opened in the Dope Sheet).

To switch directly from Dope Sheet to the Graph Editor you can press CtrlTab.
Also, the Only Include options may be useful sometimes to only see the keyframes of the selected bone(s) but don't forget to disable it if necessary:

LEGEND!! God I have been tearing my hair....The arrow at the end was the key. I followed your instructions and got my dope sheet back...the one I had set up to make the screenshot. But the lower dope sheet still did not show...it was "only include" option I had switched on that prevented me from seeing it.


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Bone in armature not copying transforms
I have a mixamo rig and mixamo control rig that can switch between IK and FK for arms and legs. I have animated extensively with the rig and its been fine, but I am having a problem in both the original blend file and the file that it has been imported into where one of the bones will not follow the transforms of the IK armature.

I have tried turning off IK constraints and using a simple rotation constraint.
I have tried putting on a damped track constraint to follow the bone (just to see).
I have checked all bones for locked IKs
I have tried turning off the constraints and putting on other transform constraints.
I have checked bone rolls, and cleared all rotation and other transforms. It should matter anyway since the the constraints are set to "replace".
I have even set up an IK in FK mode, and I can see the control rig for FK working properly, but the bone in question STILL will not copy the transforms of even the FK.

I am completely stumped. It's been working fine and then suddenly it isn't. The IK-FK relationship is working fine on the other arm. Note the picture below. The control object is for IK, and the bones for the IK rig are working as expected, but the main bone just refuses to copy the transforms for the IK bone.

If I try changing the target/owner relationship, or the blend mode, the arm moves but it still does not change with the transformations of the owner bone.
Does anybody have any ideas as to how I might resolve this?

This has been driving me crazy - does no one else experience this? Is there anywhere else I might go for some more help? Basically it seems to be an issue with a Mixamo Rig where the IK controller is using a copy location transform. What's weird is that the rig with the transform is working properly, but the rig that is supposed to follow that rig is not. Trying to solve this has cost me days/weeks in time and working around it is a major headache.


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Mesh is subtracting in CURA
When converting to stl and slicing in CURA, the 2 meshes are subtracting. Why? Normally they merge.
I put the file here: https://www.thingiverse.com/thing:5398348

The normals on the model are mixed up, you can clearly see there's a problem when you import the model in cura and it shows top faces as red for no reason,
open the model in blender in edit mode select everything and go to mesh -> normals -> recalculate outside (or inside)
You can fix normals on cura too with "mesh tools" if wanted


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set bones in edit mode to object mode position
Somehow my bones have a differed position in edit mode and object mode. I have deleted all timeline transformations and rotations of the bones (pose mode). Also there is no mesh parented to the bones. I have tried Alt+r in pose mode, but that does not give the same position as in edit mode.
How can I set the bones in edit mode to the position in object mode?
Nothing in pose mode:

Object mode position:

Edit mode position:
(note his right shoulder joint is clearly not the same positions and more bones are wrong)

hello could you please share your file? https://blend-exchange.com/

I figured out how to set the object mode to edit mode.
⎇ Alt + R for rotation
⎇ Alt + G for translation
⎇ Alt + S for scale

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.


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How to animate faster
I made Satan and added bones etc. Now I would like Satan do dance the Macarena.
I only need to see the bones, but with everting turned off it is still to slow to properly see the bones move. How can I animate the bones without the file being so slow?
I only need to see the mesh for some frames, not during animation. So turning the mesh on and off manually is no problem.
Here someone said disabling collections works, but it does not in my file.
Blender file is slow, cannot properly animate or texture because of loading speed

With Frame dropping I see barely any frames, with show every frame it goes to slow and I can't properly see the bones move.
blend-exchange.com doesn't seem to work, but the file is also here https://cults3d.com/en/3d-model/art/satan-south-park You can see I could not really make him move nice, just made 5 positions and rendered it.

Hello, could you please use another platform to share your file? You say that Blender is too slow, this is what happens if you try to animate a too high-poly mesh, is it the case? Try to stay as low-poly as possible, use a Subdivision Surface modifier with a level of 1 or 2 in order to smooth the shape

i am not sure whether Satan wants to dance Macarena.... :D

well...the model has > 2.7 mio vertices and > 5 mio triangles...so i would say: no wonder it is that slow. I would either use another model or try to decimate the vertices/polygons by decimate modifier

in the outliner, search for subdivision -> delete or deactivate all -> then the animation is quick. I don't know who just added these subdivision modifiers without thinking, but at least a lot are way to high


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How to make same face copy of cube to other adjacent faces?
I have a cube that consists of some text & images on one face. I want to make the same face as the other two sides of the cube as shown in the image. Any solution will be appreciated.

all you have to do is to adapt the faces in UV editing like this:

or...as Allen proposed:
choose UV -> Reset

If you delete the existing UV and create a fresh one, every face will cover the entire UV space.

@AllenSimpson: damn...that easy! Thank you!!!!

Thanks, sir for giving idea to solve. But I want to use an array modifier as the text fields I used are dynamic(text will be imported from a CSV file). But don't configure how to solve?


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How do I find a face with too many edges?
I’ve downloaded a free obj from internet.
And there seems to be a face with 7 edges hidden somewhere in which I cannot find manually.
I need to keep it down below 4.
How do I find faces with too many edges, and how do I eliminate it?

Hi :). Select > Select All By trait > Faces by sides. Then you can specify to only select faces with 7 sides :)

In Edit mode, Select > Select all by Trait > Faces by Sides and on the lower left settings dialog that appears increase the Number of Vertices to 7. It's probably best to be in wireframe mode (ALT-Z) for this in case it's an internal face. You'll then have to decide the best method to remove the face (dissolve, delete, merge vertices, etc.).

You can also select 'More Than' or 'Less Than' your given parameter.. eg 'More Than' 4.


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How does the multiply color node work?
How does multiply shade node work? I've found similar question, but in that case it's a "difference" parameter. What about multiply then? I've tried to look for it in Blender documentation, but didn't found any of formulas or good description.

multiply is described here https://docs.blender.org/manual/en/latest/modeling/geometry_nodes/utilities/color/mix_rgb.html#examples or are you looking for something else?

@lemon I mean, there is a formula for color difference - Color = |Color1 - Color2| * Fac + Color1 * (1-Fac). But how it will look for multiply color node? Should I just replace minus with multiply, or it will look different?

Multiply simply multiplies red of one image by red of the other image, green of one image by green of other image and blue of one image by blue of the other image.
Since color components are in range $[0, 1]$, multiplication always reduces the value.
Factor lerps between the A and the result of the above multiplication. These lerping is what Mix mode does.
Therefore Multiply with a Factor $= x$ is the same as Multiply with a Factor $= 1$ passed to Mix with a Factor $= x$:

The purpose of Distance → Compare is to show both upper Multiply, and lower Multiply + Mix are equivalent (same color result).
Math Formula
The Multiply with Factor $ = 1$ is simply $A × B$.
The Mix (lerping) is $(1-f)A + fB$, or as Marty Fouts puts it (link below), it's $A$ plus the difference between $A$ and $B$ multiplied by Factor: $A+f(B−A)$.
Therefore Multiply with Factor is: $$(1-f)A + fAB$$ or $$A + f(AB - A)$$.
More reading:
What does the MixRGB or Mix Shader node factor do exactly?

So, the formula for multiply color "Color = |Color1 * Color2| * Fac + Color1 * (1-Fac)" is not correct? I just can't figure out the math part of it.

@Сергей see edit.

Just what I needed. Thank you!


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Can I convert color attribute to mask?
Good day. I need to adapt blender material to UE5, but this engine doesn't support color attributes, so I need to replace it with texture mask. Can I convert these color attributes to masks? Blender's version 4.0.2

You can bake the Vertex Paint onto an Image Texture if this is what you are looking for?

@moonboots maybe, I just don't know what exactly I'm looking for. How can I do that?

this is weird, I'm pretty sure UE5 supports vertex colors https://docs.unrealengine.com/4.26/en-US/BuildingWorlds/LevelEditor/Modes/MeshPaintMode/VertexColor/MaterialSetup/Color/

@Alex oh, yes, you're right. Maybe I missed something, but if I have colormap1 and colormap2 I can't get access to one of them. Need a little more time to find out, and I will happy if it's working with layers, but for now only moonboots solution is working.

If UE5 doesn't support vertex colors (?), you can bake them onto an Image Texture. First thing unwrap your object, create an Image Texture node in the Shader Editor, give it a new image, keep it selected if you ever have several Image Texture nodes in your material, create an Input > Attributes > Attribute node, plug it into the Output node. In the Render panel switch to Cycles render engine and under Bake choose Type > Emit, click on Bake:

Are you sure it should be Emit? I've seen people using diffuse > Influence: color > Output: Active color attribute. Will I get different result in this case?

It should not make any difference


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Where I can find Blender's tiles material?
I want to work with uv in my project using Blender's stock material - tiles with uv numbers. For that purpose I need to assign that material to object, but I don't know proper name for it and don't remember how to find it. Can somebody remind me, where is it located?

You can get the tile texture when you add an Image Texture node in the Shader Editor. Then click on the New button.

In the opening dialog box you can then choose the size of the image and if you want a Blank image which be filled with the chosen color or you can either choose the grey UV Grid or a Color Grid instead of Blank.


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Clothe pass through/enter other mesh
It's a been a week since I'm trying to figure out why my cloth pass through other objects. I just want to add a cloth to my final render (img on the right) but it keeps passing through the bottle and the packaging.
I read topics and applied settings like in Cloth passes through Rigid Body but same result (image on the left). I rebuilt a side of the packaging without the hole and nothing new. Here is the blend file. Thank you

I just make a simple demo, it's ok.I think the main problem is your mesh,it's totally disaster...almost no loop quads，it's usually bad to use ngons and connect many lines to one point.Try to make the model again.

OMG, thank you! What do you mean by no loop quads? I mean to this shape I started with a plane then extruded to the point when I used the shear tool and extruted again. Do I have to add faces (Ctrl+R) by myself? Clearly mine doesn't have all those vertices.

modeling looks easy but in fact there are much technique to  learn, especially animate them.Pls refer to this video,you might understand what I'm talking about. Adding faces is meaningless,because your mesh is wrong,blender don't understand what you draw. https://www.youtube.com/watch?v=uQmNXCOh4MM

I tried to remake the bottle as I know how to do with the packaging but .. Is it the same process?

And thanks for the link

Pls send your demo.It also works to me. I guess maybe you are under the edit mode,pls turn to object mode.

In the file there is the bottle from my original blender, that is a disaster like the packaging.
Also there is the bottle in the middle that I built using quads but gives a square shape at the bottom and top rather than round. It works very well like you said.
And there is a bottle that I started with a circle and careful tried to add quad but gives the same effect than original bottle here --> Blend file

two steps:1.ctrl+A, apply scale;2. go to Physics Property in the right, clear all the bake.Then it's ok.

You're my hero, thank you so much. I have to learn how to use quads because I want to animate most of my stuff now. Thanj you again!


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Why are my keyframes being deleted when I reload my linked rigify rig or reload my scene file?
I have linked a rig into my scene, applied library overrides and animated it in Pose Mode. When I reload the scene file or reload the link file (in Blender File section), all the animation keyframes are deleted.
I am using a rigify rig.
I have other rigify rigs in use which do not have this problem.
There are no keyframes in the linked rig file.
Does anyone know why this is happening?
Best
Gary

I've solved it.

For those who are interested, there was an 'action' hidden in my rig file (I must have created it by mistake) which was interfering with the library override keyframes. I found it by routing through the Data API tab and then looking for it in the Action Editor. Once I unlinked it from my rig, it became Orphan Data. I deleted it from the file and now my rig keyframes as normal. Hurray!!

maybe write that as your own answer -> this is possible and wanted here

Ah, will do Chris! Thank you.

For those who are interested, there was an 'action' hidden in my rig file (I must have created it by mistake) which was interfering with the library override keyframes in my animation scene file.
I found it by routing through the Data API tab and then looking for it in the Action Editor. Once I unlinked it from my rig, it became Orphan Data and I deleted it. Now my rig keyframes as normal. Hurray!!

thank you, same problem here and couldn't of solved it without this, but it isnt just the action editor any keyframes will interfere with the linked rig


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Keyframes suddenly not interpolating or being read on specific bone/rig
I have situation where I am trying to animate an IK rig and the animation is not being interpolated and sometimes not being read from the key frame. Other parts of the rig work fine. In fact I have an animation on the other foot, also IK, and that works fine. I can't figure out what might be the problem. I suspect it is some form of bug/corruption but I am really hoping someone might have run across this before and might know of a way to get around it.
Here is the position of the foot that is not being read:

And here is where it "should" be:

I am trying to animate the foot that has hooked underneath the bar (coloured), to resting on top of it.
The two screenshots are at the exact same frame.
Initially I blocked the positions and the keyframes are in bezier mode so they should interpolate, however they jump to the blocks without interpolation, and sometimes do not read at all.
Navigating backwards frame by frame along the timeline using the arrow key, the frames DO interpolate.
I tried inserting keyframes/per frame along to force the interpolation, but that did not work either.
I tried tweaking the pole target,
I tried restarting Blender,
I tried on a different computer (Windows) and that was worse. I couldn't actually move the rig at all (just the affected controller).
The other foot can be moved smoothly, but this one moves jerkily when I try to move it around.
The other controllers on the foot (ankle roll for example) moves smoothly.
I checked previous files using this rig. In one of them it has the problem, and in the other it does not.

My current option appears to try to reconstruct the whole thing, and import the rig that does not have the problem, but it's an immensely complex animation, I'm doubtful that will work. If anyone knows anything that could help I would be extremely grateful.

Having spent 4 or 5 hours puzzling over this I DID find what the culprit was;
It was a bone constraint that I had turned off that was still affecting the foot control:

I tried turning it off, AND turning off the influence, and neither had any effect, but that was what was causing the issues. Removing it entirely rectified the problem. I had used in for a previous animation and is not yet needed for this one.
I think this post should remain in case someone else runs in to the problem. Some kind bug, but too much hassle to report.

... and if you right-click the wrong way, blender will punish you!  ;)


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How to avoid Artefacts Using Boolean Modifier on Ocean
I am animating a Rowing Boat using the technique described in this video:
https://www.youtube.com/watch?v=q2G1liNkhcw
In order for the boat to be floating in the ocean, boolean modifier has to be set and the boat copied and turned into a convex hull. This is hidden in renders but you use it to cut a hole in the ocean. However it leads to artefacts that renders the render unusable.
I have tried different bool methods, and the exact works best but still really bad. I need to find a solution to this. All I can think of at this stage is to some how render the boat separately without the ocean and overlay it. But that would be a bit awkward and fiddly.
I've tried adding a subsurface modifier (in between ocean and boolean), but maybe I am not cranking it up high enough? I've also tried reducing the size of the ocean but that hasn't worked. I guess cranking up the resolution of the sub surf might help, but that would likely increase render time.
Any advice gratefully appreciated.

I'm not sure I can tell what artecfacts you're referring to. Can you share your Blender project file? Instructions for sharing.

Thanks for your response. No it's not really practical to share - it's too large. The top picture shows only slight artefacts, the bottom picture shows it severely. The result is flickering between them. Right now I am trying cranking up the subsurf modifier to 4 and changing the solver for the boolean to "fast". Unfortunately it does look like it will impact render time.

NB....the renders flicker between the top and bottom pics. I might be able to link a short bit of video - that might show it better.

Adding more subdivs to before the boolean mod is not going to help so def stop doing that.

I hear you loud and clear. Have just stopped it. You are quite right it did not work.

So it seems the only solution is to create a layer for the boat (and hold out the oars) and composite them separately. The boolean trick is just a mess.

Yeah, that was also my first instinct as well. Fix it in the composite.


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Cannot combine 2 translated/transformed images in Compositor
I am trying to combine 2 movie clips (actually the same clip which is transformed twice) which are overlays to my main scene. I want to use the same movie and scale them on the x-axis then mix them side by side and combine with my main scene using the mist pass as a factor for depth. Standard stuff.
However, I cannot figure out how to combine the 2 overlay clips. No matter what mix node I use, or work-arounds, blender only displays one of the transformed clips.
Here is the node set up:

NB...it doesn't matter that I have used just one clip as the source - you get the same result when it is duplicated along with the scale node.
Here are the precise steps to replicate:

Use an image as your main scene.
Find an image to use as an overlay
Use the scale and transform nodes to create 2 images from a single source, one for the left side of the screen and one for the right. The aim is to combine them - a way to get an overlay to look like it was shot from a greater distance and a slightly different angle.

Theoretically I should be able to combine them in a mix node, or an add node, but they do not work. I tried alpha over and I also tried to combine them with the main scene separately. I tried all the various modes for scale - absolute/scene size/render size, but it really needs to be "relative" in order to warp the aspect ratio the right way. I tried the transform node and every permutation I could think of, and that does not work either.
It's puzzling. I would have thought what I was trying to do was fairly straight forward compositing. I'm sure there is something I am not doing wrong, but I can't figure it out, and there does not appear to be anything on the internet that I can find that explains it.


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Render Layer Mask Best Practise

I have an already rendered scene that I would like to put a fog overlay onto in compositing. The scene already has volumetrics, so I am compositing:

Env
Volmx
Main Scene
Fog overlay

The fog overlay works really well even though its slapped on top of everything, but I would like to get it better to fool the eye even more. What I'd like to do is take the objects selected in the screenshot and create a mask so that the Main Scene punches through the fog overlay.
I understand the principle, but I am wondering how best to do it. Also, I should be able to render it out quickly since I don't need their textures or any light information. So my questions:

Do I use a "View layer" or Linked Scene? Surely if I use a "View layer" then any alterations to the render settings will affect the main layer? Linked scene would mean I could have different render settings and any changes to camera, animation etc would be reflected in both scenes (in case I need to re-render or set up another shot).
My understanding is I need an alpha for the background and a solid colour (black) for the objects that are masking. How do I set that up?
What render settings and renderer? I guess it doesn't matter, but what is fastest most efficient?


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How to Lock 2 NLA Strips Together
I have worked out a way to combine two CMU animations where the final and start local locations and rotations around the same world position is different.
To clarify, if I import the bvh for 2 different animations, A & B, the end position of the armature will be facing a different direction and in a different location around the origin point. To join the animations, I copy and paste the keyframes from one bvh armature to the other. The armature jumps from one position (the end of animation A) to another (the start of animation B) at the join between the 2 animations.

To fix the jump, I parent the armature to an empty with the exact rotation and location as the hips (I call position offset). (TIP: I do this actually by parenting the empty to the armature/hips (the root bone) FIRST and the removing parent but keeping transformation). Then I repeat the process for the target location. I then use an object constraint (copy transforms) for the empty the armature is parented to and set the influence to change from 0 to 1 at the exact frame of the switch between the 2 animations....when the armature jumps to a new position.
The armature then inherits the exact position of the first animation, the hips having the exact same world loc/rot as the end of animation A. It works perfectly. Then, making sure not to include the hips in this, you can smooth using option-O all the jumps of the other bones and the 2 animations blend seamlessly together. It actually works really really well.
N.B. You have to transform the hips/armature at object level - ie object constriants, it won't work with bone constraints.
N.B. Be sure not to smooth the hips keyframes! They have to be exact, the last position for the first animation and the first position for the second. Then your empty will move them to the exact right position and you'll get a seamless transition.
However:
I would ideally like to be able to export this as a new animation. It isn't possible unless you attach empties to each of the bones and export those as a bvh, but that's too fiddly. If you simply export the animation, the new loc/rot position isn't carried over. Baking doesn't work.
But if I could lock the NLA strip of the Object Constraint to the armature animation, then I could move the NLA strip around without worrying about the position of the animation of the object constraint.
To do this, according to the manual, I can group them and turn them into a "Meta-Strip" and they should theoretically move together. However it does not work. As soon as you select the armature (to select the NLA strip) and move the strip, the object constraint animation does not move together with the animation strip.
Does anyone 1) know of a way to lock the NLA strips, 2) a way to bake the entire animation into 1 strip 3) a better more efficient way of combining animations like this?

It sounds to me like the problem is mostly one of, how to get this animation exported conveniently, without the animation depending on inheriting from a bunch of empties.
There is a pretty simple way to do this, starting from the file that you have:

On first frame, unparent the armature object.

Go to first frame of "second" action (looks like you've already merged them.)  Disable the copy transforms constraint on your marker for the second root, "Empty - X-bot Position Offset".  Give your root bone a child-of bone constraint targeting this empty.  (Blender should set the inverse automatically.)

Re-enable the copy transforms constraint on the empty.  Play your animation and check.

Now, the animation no longer depends directly on inheriting the transforms of any empties, so those empties are not necessary to the animation once your export bakes visual transforms.
If exporting is not the issue, and you want to move this action around on the timeline, you can simply bake the root bone ("bake action": selected only, visual keying, clear constraints, replace action) to write the the child-of into the action.
I'm not sure that this is the best technique for dealing with this on a more general, long-term basis, but for what you already have and for your immediate needs, it seems like the simplest solution.

I am looking forward to trying this, but can you point to a better technique for combining 2 CMU animations (or simply 2 animations that have different local positions finishing and ending  around the same origin point)? I tried adjusting the keyframes for the hips to match the start and end, but it completely messed up the animation.

Oh I re-read your reply. I have already tried a child of bone constraint in the manner you suggest and it does NOT work. What will happen is the hips will be pinned to that location and not move. I will double check tomorrow but I am 95% sure this will not work. Did you try it?

@DrignatiusCole I tried it.  I'm describing what I did.  Tested on a fresh copy of your file.  Hips will move because the empty they are a child of will move.

Thanks, but thanks to your post it gave me another idea to try which I think works better. Using the same technique of passing on the correct rotation and position via parenting, I set a key frame for the armature at object level for the last frame of the 1st animation, I then set object KFs. That means all KFs are associated with the armature rather than mixed. I could then bake the animation....on baking in the NLA editor, you have to select pose AND (shift-click) object and visual keying. I then had a complete action I could append.


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How can I paint specifically the vertices underneath another mesh?
I have a base body and make clothing for it, but in the game we use an item mask (just a texture of the body that's white, but black underneath the clothing) to clip out the parts of the body underneath of the clothing. Currently we just make it manually by painting black on the body texture where the clothing is. Under the assumption that it is skin tight, how could I go about using the holdout material (or if something else is better) that every part of the UV is blacked out that is underneath the clothing. I looked into vertex paint and a few UV projects but wasn't able to figure out how to go about doing it.

You might be able to do this by putting a white emission shader on the clothes and baking emit with selected to active checked. Something like this:

You'd have to invert the image after to get it to be black under the clothes since the bake will use black whenever it's rays don't hit anything.
If that doesn't work maybe look into dynamic paint, you could probably accomplish something similar with that.


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convert OBJ file to GLTF with only CLI
is there a simple TERMINAL ONLY way to convert an .obj file .gltf file using blender,

with blender GUI i can do it like,

file > import > .obj > [~/path/to/input.obj] > import .obj

then:

file > export > .gltf > [~/path/to/output.gltf] > import .gltf

maybe for ex:-
blender -i ~/path/to/input.obj -e ~/path/to/output.gltf

like [-i for import & -e for export]

is there a way to do this using a bash terminal, like ffmpeg or convert [ImageMagick] do file format conversion

https://blender.stackexchange.com/questions/192420/how-to-import-obj-and-convert-and-export-as-fbx-from-command-line-in-python https://blender.stackexchange.com/questions/56009/how-can-i-convert-a-file-with-the-command-line

UX3D offers a conversion script, calling Blender in headless mode from the command line: https://github.com/ux3d/2gltf2


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expel object from isolation mode
I recently switch to Blender 3.2
I quite often go into isolation mode. When I done with some part I wanna expel (don't know how to call in properly, sorry) an object I no longer working on from isolation mode. It was previously done by hitting "m", but now this key is universally for switching collections. I asked google what is the new keyboard shortcut, but it don't understand what I looking for.
When I tired of googling I "overcoming" the problem by selecting "a" to select all. Deselect by hand objects I don't want in my isolation mode. Then "/" to end isolation mode and then hitting "/" again to isolate only objects I need. The problem is the file is big The whole procedure takes approximately 5 minutes, because loading all the objects. I getting tired of it.
Can someone tell me what is the new shortcut?
(Sorry for bad English)

I think you're looking for menu entry View > Local View > Remove From Local View with shortcut Alt+Numpad /

I've always just hit forward slash "/" on the numpad to toggle between the two states. This just works on the object which has been selected in Object mode of course.

THX! @Blunder it is what I was looking for.


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Sapling tree gen add-on - rotate branches longitudinally
I am interested in creating a fern with this tool. Unfortunately I can't get the 3rd level branches to rotate so that they're facing the sky, instead it only seems possible to have them parallel to the 1st branch (trunk) whereas I want them perpendicular. "Split angle" seems like the correct property to change but it doesn't seem to do anything at all.
I have set the "rotate angle" to 180 so that they're all parallel with each other, unfortunately I can't get them to all rotate 90 degrees.

I am using Blender 2.79b but also tried this on 2.90 and had the same problem. Is what I want actually possible with this add-on?


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Particle instance modifier ignoring particle rotation
I need to use the particle instance modifier to make an object be emitted that bends with the hair of the particle system. Think leaves being emitted and bending along the hair curve. Only thing that doesn't work is that I can't get the "leaves" to always face upwards, adjusting the rotation options in the particle system appears to have no effect. The z-rotation of the leaves always seems random no matter what. How can I make it so that the leaves are always facing upwards?

I am using Blender 2.79b


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How do I have two perspective views for sculpting?
I am learning to sculpt in Blender and I ran into an annoying problem. The problem is that when I move the mouse, the tool moved in parallel to the screen. I was hoping that quad view would solve the problem. But you can have only one perspective view there. How do I sculpt working with different views seen from slightly different angles?

I have tried menu / Window / New Main Window and seeing sculpting from two different perspectives side by side. It is almost what I want but the problem is the other window is updated only when I lift the finger off the mouse. I there a way of having a live preview form the other angle?

You need to put your mouse as on the picture below (on this narrow black line between viewport and editor type) and right click:

than you can choose between horizontal or vertical split and left click on the place where you want to split your viewport

now you can scuplt in both areas :)

there is a place on that line where you do not get the options. That < symbol on the edge of the screen when hovered also displays <==> but with the options to split the screen. That is why I was confused. But thank you for your help.

In Blender 3.6.2, press spacebar to start animation playback, and start sculpting. Ctrl+Alt+Q to view in quad mode. All viewports update in real time.


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Query if modifier exists on listed objects
I'm new to Blender and the way it works with Python, so I still don't understand quite well the way the different commands work.
But I wanna create a small tool where i can assign a modifier to a list of selected objects and play with the properties.
So far I achieved adding the modifier to the selected objects, but if I happen to create new elements and select all objects in the scene I need to find a way to query which objects already have the modifier and which do not. So if I run the script again, only the ones without the modifier get it, otherwise it gets duplicated.
So far I haven't been able to find a way to do this using  bpy.context.selected_objects , I don't know if there is another way or if i'm using it wrong.
Here's the script i have to apply the modifier:
import bpy

objSel = bpy.context.selected_objects

for i in objSel:
   if i.type == "MESH":
      subD = i.modifiers.new(name = "Subdivisions",type = 'SUBSURF')
      subD.show_only_control_edges = True

Any help is appreciate it!

Related: Check if active object has a modifier

You can access each objects modifiers as a dictionary by Object.modifiers. Then simply check if the name or type of your modifier is part of modifier collection (Modifier.name/Modifier.type) otherwise add a new modifier using ObjectModifiers.new() method:
import bpy

mod_name = "Subdivision"

for obj in bpy.context.selected_objects:  # Prefer using explicit variable names. Generally, i is used for counters, not objects
   if obj.type == "MESH" and mod_name not in obj.modifiers:
      sub_div = obj.modifiers.new(name=mod_name, type='SUBSURF')
      sub_div.show_only_control_edges = True

Related: Check if active object has a modifier

Thank you! This is exactly what I wanted. I'm used to work with python on Maya so finding the way to do the same things in Blender is still a bit tricky for me.


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How can i texture the whole thing on surfaces that are created with an active boolean modifier?
The object isn't textured on surfaces that are the result of a boolean modifier. I tried generated, uv and object input for the mapping but they all have the same results. Different uv unwrapping methods don't change anything either. I don't want to apply the boolean modifiers because they are animated. For example the holes open up by scaling the boolean cylinder from x&y 0 to 1. I made the same animation without boolean modifiers, instead with shape keys but it distorts the texture and doesn't work out properly, so i want to keep the boolean modifers unapplied

Have you tried adding your texture to the modifier itself as well as your main object?

Thanks a lot, that fixed it perfectly!

Good! I don't know why it works, but it does for me! :^)


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Why does the turbulence not affect the particle system?
I want to make a smoke trail behind a flying object by emitting particles and make a smoke simulation with it. I parented a turbulence to the emitter so that the particles don't fly out too straight. But the turbulence doesn't affect the particles. And is it possible to emit the particles in smalle timesteps because when its moving so fast the particles are separated a lot from frame to frame...

https://we.tl/t-MugEkhVqxR

You need to increase the Strength of your Turbulence. As for the slices of particules, instead of using a plane you could use a cuboid (juste extrude your plane to do it) and choose Emission > Source > Emit From > Volume (as it's already the case), here is what it would give:

But to have a similar effect you could just increase the velocity Randomize value:


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How can I make this launch better?
I tried to launch this pawn away with some rigid body physics, but it just slides off and doesn't look very convincing in terms of speed and the overall movement. I like the way the square flips up but it should launch the pawn accordingly. What settings need to be added/improved?
the blend file

You could create another object that you'll make invisible and that will be the one that will really push the pawn, make its movement fast so that it's more powerful than your square:

You could also cheat with some keyframes. Create one locrotscale keyframe for your pawn when it's on the square:

Create a second locrotscale keyframe where it's supposed to be ejected, plus a keyframe on the Animated option off:

The previous frame, enable the Animated option on and keyframe it:

Here is what it gives:

poor little pawn...you are so cruel!!

Chris, this is all fake, no pawn has been hurt actually, how don't you know that after all these years

whaaaat? really.....? and u and moderators...all fake!?!??!

of course, and you are in a matrix


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Why is the background so full of noise?
I rendered this animation of a coffee mug with a smoke simulation to create the hot steam but the background is almost distorting like with heat distortion. I do use depth of field and the focus shifts from the mokka to the mug, but the entire kitchen background flickers way to much. The resolution is 1080x1080 at 150% with the standard noise Threshold of 0.01 and 128 samples with a tile size of 256. At first i rendered with 64 samples and then again with 128 but nothing changed.
Does the smoke domain distort in addition to the depth of field option or maybe it has something to do with the animated cloud texture that is used by the smoke emitter?
Animation result
project file

Could you share a screenshot?

Does this answer your question? How to avoid noisy renders in Cycles?

a screenshot doesn't show the problem, it only shows in the animation, i linked a youtube shorts video of it

Try 10 000 samples. That will fix it. It's always samples. If that's not practical , real depth of field is noisy, consider using compositing and blur based on Z pass instead.


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How make solid object follow cloth sim (eg. grommet on flag, button on clothes)
I'm trying to make a flag using a cloth sim and wind physics, but I can't figure out how to make the grommets (the metal rings that attach the flag to the pole) follow the cloth sim.
I assume this must be fairly straight forward as a similar concept would apply to attaching buttons (and other solid objects) to clothes? How is this achieved?

I'm working in 2.79, so hope it's the same in whatever version you have.
If you've done a simulation you are happy with, you can "Bake from Cache". Then use the "Make Vertex Parent" function:
Select the object you want to have follow the simulation, then select the cloth object. Then go to Edit mode, and select the vertex nearest the object that is to follow the simulation. Go to Mesh/Vertex/ Make Vertex Parent.  Come out of Edit mode, and the object should now move with the baked cached animation.
Edit:  when I tried this yesterday, the object wouldn't move with the simulation if I used the menu item to parent it to a vertex on the cloth, until I cached the simulation and baked it. But now I find that caching and baking isn't necessary if I use Control P instead of the menu item. A bug I suppose.
Edit 2:  If your object is elongated, you'll no doubt have a problem with orientation.  In that case, you can place an empty at both ends of the object, make the empties into children of the nearest cloth vertices, then "hook" vertices on each end of your object to their respective Empty.
The hook command is under Mesh/Vertices/Hook/Hook to selected object - you have to have, in object mode, selected the empty first, then the object, then go into Edit mode so you have access to the objects vertices. The object will need all vertices parented to the one or the other Empty.


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How to set material underneath a texture?
I am have this image and I'm trying to set the black background color to match the rest of the extinguisher. I tried messing around with some settings like Emission and subsurface color, but that messes with the image. Any help with my personal project would be greatly appreciated. Thank you :)

you'll probably find the answer here: https://blender.stackexchange.com/questions/46424/add-a-transparent-image-on-top-of-a-material/46447#46447   or here: https://blender.stackexchange.com/questions/32997/how-to-place-a-png-texture-with-transparency-over-a-material

Does this answer your question? Add a transparent image on top of a material

Prepare the sticker image, give it a transparent background (Alpha 0%). Select the faces where you want the sticker to be displayed, unwrap them, give them a new material.
Prepare your node setting: Create an Image Texture and load your sticker picture, plug it in a Diffuse node. Mix this Diffuse with another Diffuse node that has your object background color (red in your case).
Plug the Image Texture Alpha output in the Mix Shader Factor input so that the sticker background appears transparent.


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Transparent object within transparent object in eevee does not display
I have 3 objects in blender. They are inside one another(think russian nesting dolls) and each one is transparent except for the inner-most object.
My problem is I cannot view all three objects through each other at the same time. I can either see the smallest object within the largest one or the second smallest object inside the largest one but never all three.

Related: https://blender.stackexchange.com/q/133780/, https://blender.stackexchange.com/q/141406/

Does this answer your question? Can't see a glass object through another glass object in Eevee


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partial fracturing
I’ve been looking on the internet but have not found any answers.
How to make an object not fall apart entirely when being hit by another object. So that it can still move around with the pieces, that where left from the first impact, saving its fractured form. more exactly to make so that every piece of an object has some value of force needed to detach it from others. How do you do this?
Thanks in advance!

You're searching for Constraints. Related: Rigid body animation with constraints and relationships

Or you could just change the rigid body's that should stay in place to passive (constrains wörk but they can be a bit finicky)


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When I render an image it comes out different than what I see in the viewport. How can i fix this?

As you can see the bevels in the viewport on the front pyramid are much smaller compared to the rendered image. This is an Eevee render.

Do you have any modifiers (e.g. subdivision), which have different parameter settings for "Viewport" and "Render"?
If so, setting the number to the same value should give you a consistent result!


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Why does the objects child not rotate around it's local z axis?
I made a simpler version of my problem but basically the cross is parented to the cylinder and should spin along its local z axis whilst the parent cylinger also turns around, but the cross rotates all over the place instead of just its z axis, the final position is correct but the movement inbetween makes no sense? here is the file and thanks in advance:
https://we.tl/t-9S6WRXeQFt

Thoose kind of problem arise from how Euler rotations are evaluated: if XYZ Euler  is choosen, Z is evaluated first, then Y, then X.
Every rot that comes after gets influenced by the formers, so that start and end orientations will be in place, while the inbetween interpolation becomes nearly unpredicatble (and this is the reason why such a complicated concept like Quaternion rotations has been created).
In the example you uploaded, to solve, go to frame 1, go to graph editor (or Dopesheet), select the cross and delete its X and Y animation channels; then set its rotation mode to Euler ZYX.
Another way to solve is to animate the cross while in horizontal orientation (i.e. facing the sky and using its Z rot channel only), then set it child of an empty, then rotate the empty to set its final orientation and set the empty child of the Cylinder.
In this way the whole coordinate system of the cross is rotated and the Euler interference is avoided.
Check some tutorials about Euler vs Quaternion rotations and Gimbal lock problems for a better understanding of the issue.


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Why is my interior Animation flickering/noisy?
I rendered an animation and the frames by themselves don't look noisy, but when I put them together in a video every frame seems to be flickering and really noisy. The lights are purposefully flickering when the objects get pulled together, but not before. 128 samples, 1080p, tile size 256, default noise treshold, openaidenoiser, light bounces all on 10. Increasing the samples doesn't make a difference.
https://we.tl/t-1CPYqX7jlt

Hello and welcome. While files, images, and external videos or links may be helpful additions they should not be the only way to obtain information about your issue. Don't make understanding your question rely on downloading a file, watching a video or visiting an external site. Use the builtin tools to upload images or gifs, along with thoroughly explaining the problem in written form so it can be indexed and searched for thus helping future visitors with similar issues.

Do you have this issue on individually stored frames or on a video?

The frames by themselves look fine but when they are played in a video like in the link, mainly the wall are flickering and noisy. I rendered them as pngs.

You write that increasing the samples doesn't change anything. To what number have you increase/tested the sample count already?

There is nothing inherently wrong with your render, your Sample count is just too low. When rendering an Image, the longer you render the less noise an image will have. When using the inbuilt denoiser, this noise pattern gets interpreted individually frame by frame. the more noise visible the more the denoiser has to guess how it should look like on every frame individually. In other words, the noisier the image the more the denoiser has to guess. As it guesses every frame individually (technical term: not temporal stable) the denoiser creates different patterns for each frame.
This is a normal behaviour of any denoiser that is not temporal stable.
What you can do to fix the issue:

Increase the sample count of your render. Try double the amount and only render 3 to 4 Frames of the animation. play these frames back and see if the artefacts persist. increase the number until you're happy with the result. then render the full animation. I recommend to choose the frames when the things are bundled up in the air.
Uncheck the denoiser in Blender and just render the noisy images. Then Use a denoiser in your editing software if yours does have one. Davinci Resolve (the paid version) does have one for example. These denoisers are temporal stable and will denoise your video not frame by frame but rather as a sequence. please be aware that this will not correct a video that is very noisy.
Use a paid Add-on like Pidgeon Tool Bag (https://blendermarket.com/products/pidgeontoolbag) To denoise your render temporally inside of Blender
Use a different Render Engine like Redshift (if my memory doesn't fail me) that has a temporal stable denoiser. This also costs money and i'm not sure if the denoise option of Redshift would actually be available in Blender
Render it using a Render Farm. Just google "Render Farm Blender" and you will find a bunch of options. This will cost money but let you increase your sample count to high numbers as they have very fast hardware.


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How do I correctly append object constraints and keyframes?
When I append a landing platform that I animated and added object constraints to (child of) into a new file everything is there from textures, keyframes to object constraints, but when select everything to scale and move it according to my new landscape, the animation doesn't work properly anymore. The moving parts skip to other locations and move far away after scaling it all down. Is that a parenting problem or how can I make sure that it still functions after scaling and moving it around in a new file?

You can try to use Copy Location, Copy Rotation, Copy Scale constraints. These constraints can be set to local space, so that only local transforms will be taken into account.

You can also choose the root thing (for example root bone) and set a custom space using this object:

The problem with keyframed animations is, the values stored in their keyframes are usually local values, always in relation to the parent object or if unparented, relative to the world origin.
Let's say you create Earth and Moon, and the Moon is orbiting around the Earth. If the Moon is a child of the Earth, you can move the Earth around and also scale it, and the Moon will keep orbiting the Earth and its size and orbit diameter will be scaled relative to the Earth's scale.
The problem is: this only works if the Moon is a child. If they are both unrelated objects, even if you select them both and move and scale them to a mutual pivot point, Earth and Moon will keep the new scale, but the Moon's movement is determined by the location coordinates stored in the keyframes - and they are relative to the world origin, if the Moon is not a child of the Earth.
The same goes for all your objects. If there are objects not parented to anything like this landscape you mentioned or have Child of constraints targeted to this landscape, then moving and scaling them will not make their animations relative to the landscape.
In this case it might be better to not move and scale all objects to the new landscape, but place/move and scale the landscape according to the animated objects. Then either parent all objects (that are not already children of other objects) to the landscape or those objects and the landscape to an Empty, and afterwards moving and scaling the Empty (or the landscape, whatever you make the "top level parent") to the desired location and size.


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Can I control the "var" of a driver manually?
I want to use a driver to open and close a hatch by rotating it on its y axis. So when I move the empty on the z axis the hatch should rotate on the y axis. I locked the empty on a min and max z value because there is something else driven by it. When i move the empty through the full range the other animation is complete but the hatch didn't rotate far enough. I know i can make it rotate further by writing var*2 or more in the driver editor but i don't want to adjust the multiplication of the var until the rotation is correct because it takes too long for multiple hatches. Is there another way to basically set the rotation that is reached when the driver is fully "extended"?

tbh this is not a blender question - but a math question. You have 2 points (x1,y1) and (x2,y2) and you want to calculate the y = mx + n function for that. (rot_max-rot_min)/(zmax-zmin)*(z-zmin)+rot_min in your case

Nice, I see you are working on a Millennium Falcon model ;) If you don't want to go for the maths behind this, instead of using drivers you could use a Transform constraint on the hatch with the empty as Target.
You can choose which transformations you want to map from one object to the other - in your case Location to Rotation, and you can use different Min/Max values. Also you can decide whether the global or local coordinates are relevant on both objects. This will be necessary since I suspect the empty and the hatches will be parented to a spaceship that can move, so the global positions will be variable.
In the following example I have an empty that can only move from +1 on the Z axis to +3. I created three sets of hatches with three different behaviours:

rotates 0° to 120° from Z +1 to +2
rotates 0° to 120° from Z +1 to +3
rotates 0° to 90° from Z +2 to +3

As you can see, 1. and 2. both rotate 120°, but the first hatch is opened quicker than the second. The 3. starts to open later and rotates just 90° (by the way, that's for the left hatch doors, the right doors have the corresponding negative angles). //EDIT: No negative angles, see last paragraph.
These are the settings of the left doors. The Target is the empty, both Target and Owner are set to Local Space so that when you parent everything to another object, they can move around with it and still work correctly.
Under Map From I chose Location and the Z Min and Max values for the range in which I want the hatch to open. The Map To is set to Rotation, important now is to set the Y Source Axis (because I want to rotate them on Y) to Z, because I want the Z value of the empty to drive the rotation. As Min and Max I set the range for the opening angles.

This is an example to show that it works even when parented to another object:

Of course there are much more settings for the Transform constraint. And just after finishing all this I realized you don't have to put Transform constraints on all doors. In my file I just have them on the left doors, the right doors have Copy Rotation constraints with inverted Y axis. This way you only have to adjust the angles for one of the doors per hatch.


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Anonymous Attributes and Capture Attribute
Can somebody please explain me the Anonymous Attributes and Capture Attribute in simpler words. How do attributes interpolate; and when Capture Attribute can be used. I am excessively simple-minded with the Manual; and tutorials I have watched didn't seem to help.

Don't worry about the documentation not being clear to you - unfortunately it's just not clear enough on many things.
The default cube has an attribute on all vertices - it has a name position, therefore it's not anonymous:

You can Modify this attribute either by using Set Position node:

Or by treating it like any other Vector attribute and just adding to it:

In both cases the attribute gets modified when the Geonodes modifier is evaluated:

Now let's say you want to change the attribute randomly using Noise Texture:

 (⬅ not synced ➡)
Now let's say you want to add another noise to only affect the Z coordinate, but affect it by a lot. This maybe could be achieved just by increasing the Z component of the Vector Multiply node, but let's say it's easier to reason about the logic by adding a separate Noise Texture:

(old Noise Texture is called General, the one just added is called Vertical)
You can see that this noise has more scale, so it's more rough, fine-grained, however, the animation part (the driver), divided current frame by two more orders of magnitude, so the added change on Z should actually be much slower than that of the first Set Position. Let's test it:

This is not what I meant by "much slower". What happens is that while the 2nd Add Node changes the coordinate very slowly, by only 0.0001 unit every frame, The 2nd Position node connected to it doesn't contain the original vertex position - it is evaluated after the first Set Position was evaluated (read this answer to understand the order in which nodes are evaluated), so the vertex positions are already changed by the first noise. Effectively, we're traversing through the noise with the speed between 0.0001 (when the first noise outputs absolute black color and doesn't offset a vertex, so the only offsetting is done by the 2nd Add Node) and Vector((0.3, 0.3, 0.3001)).length = ~
0.52, which is a lot for a noise of scale 20.
To solve it, you need to access the original position. For example by reading it from the original geometry using the Transfer Attribute node:

Now it works as it should:

How does this Transfer Attribute node work? Current geometry has the same number of vertices as the original geometry. Also, each moved vertex has the same index as the original vertex. So by passing the currently evaluated vertex's index (and I'm doing that by not connecting anything to the Index input of TA node), and passing the Position field, the position of the vertex with the same index in the connected geometry is read - the original position.
Finally, rather than transferring, you can just save the original position and pass it along the geometry:

The effect is the same, but now the geometry contains this additional attribute. However, you don't see it in the spreadsheet, because you never output it, so it's discarded at the end, without a name - it's anonymous. You can confirm it resides on the geometry by attaching a viewer:

Finally finally you can output it and give it a name to save it:

Thank you a lot!! But I have several questions, if you will.
First of all, we can use capture attribute instead of attribute transfer for the same result, right?
Secondly, (very stupid question, probably) how the vector input in Noise Texture works, and how does it affect the Noise Texture itself?
And lastly, we use Attributes in order to store information of object in some state, which we indicate (e.g. original position at the start)?
And sadly, I did not understand the reason of the object phasing through itself. Could you, please, explain it again?

@Asc 1. In this specific case TA and Capture can be used to the same effect, but notice the layout differs - in TA case you read from the original geometry when you need it, in CA case you save from the original geometry and pass the field forward. I think CA is more readable, because it's immediately clear you're reading previously saved value for the same element (same domain, index, geometry), just a previous version of it. In case of TA you could for example read a position of an edge of another object with the same index as the current vertex's index: https://i.imgur.com/lY2gp4v.gif

@Asc 2. Imagine that you design a location in Blender, and create an API, where someone can ask what's on coordinate X, Y, Z in that location, and the API responds for example "a tree". Noise Texture is like that, except it the location is clouds, the response is color (how dense is the cloud on that X, Y, Z coordinate), and rather than the location being generated and stored, it's just computed based on some mathematical formula based on the inputs - the vector location, the scale (actually all the scale does is multiplies the vector) and so on.

@Asc 2a. So if you change Vector, you move inside this world. If the change of the vector is small enough and smooth, it feels like traveling through the world https://i.imgur.com/zhpmdb2.gif  3. I didn't actually explain why the object phases through itself, because it's irrelevant... But it's simple: the output of the noise texture is between 0 and 1. Then the Z component is multiplied by 20, so now it's between 0 and 20. The height of the cube is only 2, so if bottom vertex is moved 20 up, and top vertex is moved 0 up, the bottom vertex is now 18 above the bottom vertex.

Sorry, but I become exponentially more confused with each of your explanations. I still don't understand the difference between CA an TA and how Vector input in Noise Texture works. I will ask these questions separetely. Anyway, thank you!


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Object -> Set origin operators
Why are operators Object -> Set Origin -> "Origin to Geometry" and Object -> Set Origin -> "Origin to center of Mass (Volume)" allocating Origin differently? I would imagine them finding center of Geometry and simply putting Origin there. What is the difference?

Blue line is the location of origin set by Object -> Set Origin -> "Origin to Geometry" operator.
Red line is the location of origin set by Object -> Set Origin -> "Origin to center of Mass (Volume)" operator.

Origin to Geometry will take the vertices density into account, while Origin to Mass will take the general shape of the volume only into account

If additional information was needed:
Origin to geometry
It is the mean of the vertices coordinates.
Origin to center of mass (surface)
Calculates the centroid of each face then the barycenter of these centroids ponderated by the face surfaces.
A link.
An illustration:

For each face, loops over its triangles (green, blue, red), calculates their centered and ponderate them by the triangle surface.
In result, calculates the yellow one (their barycenter).
Do that for all faces and calculate the overall barycenter.
Origin to center of mass (volume)
Calculates the centroid of each volume (see below) then the barycenter of them ponderated by their individual volumes.
A volume here is made of a tetrahedron composed of each face triangle and a reference center.
This center is itself precalculated as a barycenter of each face centroid ponderated by their amount of vertices.
A link.
An illustration:

For each face and from the center calculates the volume for each tetrahedron (green, blue, red) and the volume center is the barycenter.
Do it for all faces and get the barycenter off all (ponderated by individual volumes).
The difference between the two former is often small, but that may be important for simulations.

So, basically, Origin to Geometry accounts only for the vertices shown in edit mode, and Origin to Center of Mass (Volume/Surface) takes in account the whole Volume/Surface Area of a shape?
I still kind of don't get your "Origin to Center of Mass (Volume)" explanation. It seems to me like you described "Origin to Center of Mass (Surface)" again. I very much might be wrong.

@Imp, I've added some illustration. A bit hard to describe as my english is far from perfect...

I kind of understand what you're trying to say. However, on the first picture you've provided, I think that the "yellow barycenter" should be closer to the red centroid, shouldn't it? That is because Blender calculates a mean out of those centroids' positions and, therefore, we get the barycenter. Correct me if I'm wrong, please.

Yes the yellow are rapidly drawn for illustration, not real things. And yes, this is the principle.

Origin to Geometry (1) will take the vertices density into account, while Origin to Center of Mass (2) will take the general shape of the volume only into account, therefore the difference:


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Casting Volumetric Shadows in Cycles Fastest Way
I am experimenting with trying to combine Eevee for volumetrics and Cycles for everything else. I have found a way to produce smoke that is really effective and much more efficient than using cycles which takes a horrendously long time to render. I am using a particle emitter to emit vdb object and set to increase to full size as per this short video.
As you can see, Eevee does not cast shadow. This was done combining Cycles and Eevee, but even with the Eevee only render, it is a limitation of Eevee that volumes will not cast shadows on solid objects.
Using this technique renders really fast - about 5 seconds per frame for cycles and eevee combined. But because the smoke is from the particle system, there is hundreds of vdb images of a cloud meaning easier manipulation of smoke, but cycles freaks out over that. Eevee renders almost instantly and it's good enough.
So what I thought might be possible is to use the volume to cast a shadow, meaning I could turn cycles volume rendering to its fastest least detailed settings and turn on indirect for the collection that governs the smoke emission. It works, but it's still really slow (though much faster than trying to render the smoke in cycles). 19 minutes versus 5 seconds!!

Does anyone know of a way we can use cycles to catch the shadow of a volume without calculating the light passes of the volume?
Is there another way to "cheat" a shadow from the volume onto hard surfaces in Eevee?

Well, since Cycles somehow needs the light passes to get the shadows (I guess that's why they are not in Eevee), I don't think it will be easy to achieve. What about disabling the Ray Visibility for everything except Shadow in the object properties? In a simple scene I have reduced the Cycles render time at 200 samples from 18.48 seconds to 8.07 seconds.

OUCH!! Sorry about that. Very embarassing. The technique worked but it doesn't look as good as in the viewport. Here is the short film: https://tinyurl.com/5e79vamt

Well, it looks like the smoke is close to the light source and therefore the shadow is very large. But without the comparison to the viewport I cannot see how good looking it is there.

You can see the shape of the cloud in the viewport version but it doesn't look like this in the render. I am going to give your Ray visibility in object properties a try. https://ibb.co/34Z51Sy

The reason the shadow looks right in view port and not in render is because the "indirect only" doesn't seem to work correctly in renders. I don't know if this is a bug or something I am not understanding. To replicate set up a volume to create shadow in a collection set to "indirect only". It looks correct in viewport but does not render.

And if you would take it out of this collection? Because my suggestion didn't need this setting.

My test work fine so far, even with Indirect Only. Are you sure it's the shadow that's incorrect or does it look different in the viewport because of other light paths...? Try to enable everything in the Ray Visibility section except for Camera. Then it will still be invisible for the camera but interact normal with all other surfaces, reflections etc. But of course this will increase the render time again.

Just to confirm, your trick DOES work. It also works on volumes that being used as objects for particles. It is still not working in my first test project for some reason I still can't work out, but trying it another test project DOES work.


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Render Passes File Output in Headless Mode
Here is the blender manual on command line rendering: https://docs.blender.org/manual/en/latest/advanced/command_line/render.html
I am having an issue in blender where blender hangs on rendering in UI mode. I can't even render an image - well I can usually render one image any subsequent attempts hangs blender on initialisation. This is both Eevee and Cycles and happens in most files but not all.
However, blender renders perfectly fine in command line mode.
I am trying to render out a scene with render passes and I have set up a file output in the compositor to render out to OpenEXR. But when I render the animation in the command line, only the composited image is rendered, not the passes. I am wondering (now that I am writing this) do I have to disconnect the image from the composite output?
What is the process for rendering via command line for render passes?