text:
Undo one line in the Python console
I'm learning Blender Python and trying a few one-liners in the console in the scripting layout. You can imagine that it would be really handy to be able to undo one line of command in the console, because obviously I'm going to often end up executing commands I don't mean to. BUT, when I press Cmd + Z (I'm on Mac), it undoes all the commands I've inputed into the console since I opened Blender. That's weird to me. How do I undo only the last command I input in the console?

I would be tempted to say that it's a bug that everything gets undone. I would think either undo should not work in the python console at all or it should do individual steps.

Doesn't Global Undo solve this?

The suggestion is ... do [not] rely on the concept of undoing any action in the Console window.

Use the Text Editor window for functions you write for long term value

By writing functions and executable statements in Python in the [Text Editor] window you can more easily test your concepts, and save your work with Blender or as an external file.
The written record is invaluable.
Clearly the [add ons] of Blender are written with a text editor and saved as files.
The console is superb for investigating structures with statement completion and dir and type.  1 to 3 lines of Python is useful. (Replace 3 with your personal Python number comfort level).  There are some add ons (probably) that will assist in the exploration as well.
In MS-Windows I use the up-arrow key to type again the last statements.
The Blender [user] interface allows a concept of configurable Undo.
Be careful not to do undo desired typing in the text editor window
If Python in the console deletes a OS file, I would not expect Python to restore it.  Not a simple example and perhaps I have not looked for an api that performs that service.

In the Blender screen capture above a function is written at the top of some file and invoked at the bottom of the same file.  Alt-A invokes the script.  There is a button as well on the menu bar .. not shown.  The above example is just some random sample and only meant to show a function definition and call of the same function.
Console for Simple Ops

When the Python Console was used for simple operations, Undo worked in the (different) 3D View window. Image above.  Console do action.  3D View Undo action.  As a quick preview for further study please note the following.  I looked at the text in the [Info] window as a means to write the text in the [Console] window. The info windows presented the Python of my manual user actions. I may have never used the the translate function before. It is no longer critical that I remember.

I agree with most of what you say but this is not my work flow. I need to quickly test things like rotating objects by a certain angle, and undoing it if the angle is not what I intended. This is best done by using the console (right?). If normal GUI operations like the rotation I mentioned above can be undone (one operation at a time), I don't see why one-liner console operations can't be undone one at a time.

The point of testing one-liners in the console is so I can see if the Python code works. Of course I can achieve the same effect in the GUI but that defeats the point of quick-testing a line of code you see? I do appreciate your help by the way, please don't think me ungrateful.

For simple ops why not do the same in the GUI and then [undo]?  I cannot know you unique workflow. Time might expire if I inquire for details. You can also do simple ops in the Console and Undo in the GUI,

You can see if the Python code works in the text editor window as well.  What is a short cut for one person may be a long extension for another person. I have no deep interest in changing your style. I am stating that style does not work for me.  The Undo issue has been minimally addressed above.  I am encouraging you to try both styles and compare.  The decision is yours and yours alone.

OK I will tray a few things and see what suits me best. Thank you for your suggestions!

You mean garbage tray of course.  Slip.


text:
Where is `OperatorList.txt`?
I've read from here about Help -> Operator Cheat Sheet, which apparently creates an OperatorList.txt file that I can read. But where is it and how do I see it? Sorry for being such a noob.

This can be found in the Text Editor, selectable from the bottom left of the 3D view.  You have to select OperatorList.txt from the list of open documents.

NB.  If you want the file to persist you have to save it as a .txt file (Shift + Ctrl + Alt + S).

Ah I see, I couldn't find the list of open documents. Thank you!

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Unweighted vertices
A custom model exporter gives me an error: "Could not load a vertex: Unweighted vertex found !"
How can I find these vertices ?

How about a little more vital information?

I need to find the unweighted vertices on my mesh.

I cannot see any vital Information in that. How about starting with the obvious things? Like which exporter do you use exactly? How does your model look like? Please take a look at http://blender.stackexchange.com/help/how-to-ask - especially the part where it says "Be specific".

Assuming either :

all groups in the object correspond to the armature (no additional groups) and there is no need to check if bones are deforming bones
or there is no armature consideration in the context

you can use this script :
import bpy

def selectUnweightedVerts( obj ):

    for vertex in obj.data.vertices: #go through the vertices
        vertex.select = False #by default deselect
        zeroWeight = 0
        for group in vertex.groups: #count the amount of 0 weight
            if group.weight == 0:
                zeroWeight += 1

        if zeroWeight == len(vertex.groups) : #select if all unweighted
            vertex.select = True

bpy.ops.object.mode_set(mode = 'OBJECT') #for an unknown reason, selecting in edit mode does not work

obj = bpy.context.active_object

selectUnweightedVerts( obj )

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What is the difference between matrix_basis and matrix_world?
I know it is a bad question sorry but I haven't found any information about these matrices expect in the blender documentations.
The docs say that matrix_basis is:

Matrix access to location, rotation and scale (including deltas),
  before constraints and parenting are applied.

So if not related to any parent, is it the same as matrix_world ?

The mathviz (currently dead wiki link) addon is a  a perfect way to experiment. Enable addon and type MW = C.object.matrix_world into python console and  a rep'n of matrix is drawn in 3d view.

matrix_basis is the 'input' matrix, so it's the thing that you set as the 3D artist, so it's relative to the object's parent. matrix_world is the 'evaluated' matrix, so it basically is matrix_basis with all the constraints applied and is multiplied by all the parent matrices (so it's in world coordinates).

Thank you for your answer ! But now the question is then what is matrix_local ? Because what you said for the matrix_basis I thought it is the local.

The API documentation actually describes the difference: "Only takes into account ‘Object’ parenting"

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


text:
Which order should one to retopologize?
So I'm sculpting a character for the first time and I wanted to ask what the next step would be, retopologizing with or without clothes? Or something different?
Does it matter? if i retopologized the body first and the the clothes over that, would that be a problem?

I guess it depends on your final goal, if it's for animation you probably need the clothes to be separated from the body

I just wanna pose it and make a turntable, if I were to retopogize clothes seperately, would i have to delete the retopology/mesh where the body under the clothes is? Or can I just have those double layers? :-)

if you choose to separate the clothes, you don't have to model the part of the body that is hidden by the clothes, if that's your question.

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


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Material appears different after being assigned to the same object

I've applied a material to my floor in this room model, but for some reason after being assigned to the object, parts of it appear stretched?
I tried moving around the origin point, but that had no effect.

are you using an image texture, and if so, how are your UV map in the UV Editor?

What happens if you apply the scale? https://docs.blender.org/manual/en/latest/scene_layout/object/editing/apply.html

It looks like you stretched the UV map while modifying your floor object

Try go into Edit Mode when the floor object is selected. Select all the faces by pressing A . Then unwrap it again by selecting Cube Projection from the UV menu.


text:
If I select mutiple objects, I can only sculp one of them
If I select multiple objects, I can only sculpt one of them. If I go to sculpt mode I can only sculpt the last object that I have selected. The outlines of the last selected one is yellow and the others are orange.

You can sculpt more than one object but you need to make sure to uncheck the option Lock Object Modes, letting you select each and switch to sculpt mode.

You will still need to select the object you want to sculpt, but they will both be possible to sculpt without going back to Object mode for each.
If you want to sculpt both objects without needing to select them, then you will want to join them together as one object until you are done with sculpting - be careful because this means you may have to reassign materials or modifiers, etc.


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Blender Animal Tracking
I'm very new to Blender and this is my second week using it. I'm currently working on a project where I want to track a lion's head in a video and add plants with physics to its head. I have a video of the lion that I'm trying to track:
Video Link:  https://www.dropbox.com/scl/fi/n2ph8to8gjt14dt74udm8/lionbaset.mp4?dl=0&rlkey=eclwypekrmvt7f69wo3n2xj6i
I'm not very skilled in sculpting, so instead of creating the lion's head from scratch, I found a free model and edited it to resemble the lion's face. Here's the model I'm using:
Model Link: https://www.dropbox.com/scl/fi/qeztv2z7l9s3t9fojpdwe/liontrack.obj?dl=0&rlkey=ftunlq92a72vlio8iuzlb9cyn
However, I'm finding it challenging to find a clear and effective workflow for tracking the lion's head and adding the object constraint to the model. Most of the tutorials I've come across focus on human facial tracking, and I could really use some guidance on the best approach for animal tracking.
I would greatly appreciate any professional help or advice you can provide. Thank you in advance!

Do you know with what camera and lens this was shot? Specifically what focallength this would greatly help get a more accurate solve.

https://blender.stackexchange.com/questions/42329/how-can-i-get-better-results-when-doing-camera-motion-tracking/42332#42332 Here is a guide for tracking

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.


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Issue with model after import from Sketchup via Sketchup plugin

It looks so bad, after import into Blender from SketchUp. Import done via Sketchup plugin from Sketchup models import. Callada does not work at all.
What do I have to do?

Since you're using a third-party addon to import a model created in an external program you should ask in a Sketchup forum! In any case we don't know what your model is supposed to look like so how can we give advice?

Hi. I would add that you might possibly get some help here if your question were edited to ask regarding your problem importing as Collada (.dae), since that is a Blender supplied import method. You say that it doesn't work at all. Maybe it has to do with some export setting you are, or are not, using in Sketchup. Also, see what, if any, Blender import options might be checked. And, as @JohnEason said, you are probably better off looking around on Sketchup's forum.


text:
A way to fix the texture UV easly

Is there any way to fix the UV without moving the UV vertices ? (This mesh has got a lot of vertices and it would be a lot of time to make them correct)
Maybe a tool like in the image editor softwares (clone tool) for UVs ?

It's available under Texture Paint.

Go to Texture Paint.
Select Clone Brush.

Hit CTRL where you want to take sample from.
Adjust Radius and Strength then paint on the mesh.

When you are done with painting don't forget to go to Slot tab and Save all images.

Thank you ! But I cannot find the "Save modified image" I have only "Save all images" but it will do nothing. Where could I find it ?

@Vettel.Sebastian Yeah, this is it "Save all images", I was writing from memory ;) I'll edit this.

But If I presss it and I go back to object mode the texture doesn't change. Only if I am in the texture paint mode.

@Vettel.Sebastian Do you have your image listed in "Available paint slots"?

I need to do with the "Material" or the "Image" Painting mode ?

If you are using image as texture select it on the list then save. I'll upload my blend file and you can check how it's done.

Or better, upload yours to: http://blend-exchange.giantcowfilms.com/ and I'll look what's wrong in your exact case. http://blender.stackexchange.com/questions/7681/why-did-the-texture-i-painted-in-texture-paint-mode-disappear/7683#7683

It's now working with the Image paint mode, but I have a problem: It changes the whole texture so all of the meshes which are using the modified texture will be changed. Is there a way to change the UV like this instead of the texture ?

There is no way to hide seams trough editing UV's, as far as I know. It's theoretically possible but I don't think that with complex UV one could achieve it.

Make sure you don't use a tiling texture, but an unwrapped one with this approach.


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How to get a bone’s Pose Mode transform matrix
With my script I want to export these values for bones:

I have tried using PoseBone.matrix_basis but I got incorrect values. For instance the expected quaternion rotation is (1,0,0,0) after export it is (0,707107, -0,707107, -0,707107, -0,707107). Can someone help me out please ?

The PoseBone.matrix_basis attribute works as expected. Use the matrix's decompose method to extract the quaternion rotation.
To test the script, open up a new file, delete everything and create an armature.
import bpy

for b in bpy.context.scene.objects.active.pose.bones:
    # use the decompose method
    loc, rot, sca = b.matrix_basis.decompose()
    # or use the to_quaternion method
    rot = b.matrix_basis.to_quaternion()

    print(rot)

Result: <Quaternion <w=1.0000, x=0.0000, y=0.0000, z=0.0000>>
If you want to use the matrix for other things you can easily make a copy with the matrix.copy() method.

Yes I decimpose the matrix before I print out, but here I got those incorrect values. I don't know why. I would share the full script but it is a private project so I can't.

@Vettel.Sebastion Ok, but the the matrix_basis attribute works as expected. It must be some other part of your script, which causes the unexpected behaviour. I'd try to condense the script in question to the core lines (untill it doesn't reveal anything private) and the share it.

@Leander could also use matrix.to_quaternion()  Going by the 1 over root 2 nature of the rotation in question could be the exporter is rotating to convert from bone y up to some other axis.  Anyhoo it's all too secret squirrel so we may never find out.

I realised that the values go wrong because before the decompose I multiply the matrix basis with axis_change which is: axis_change = mathutils.Matrix(                         ((1.0, 0.0, 0.0, 0.0),                          (0.0, 0.0, 1.0, 0.0),                          (0.0, -1.0, 0.0, 0.0),                          (0.0, 0.0, 0.0, 1.0))   is there a way to change the axis order without causing the broken values ?


text:
Shrinkwrap stretches, distorts the object when applied
The look that I am trying to achieve is to have the hexagonal shapes on top of the base mesh. But the hexagonal shapes are getting stretched and distorted. I do not want the Hexagonal shapes to change shape, but just bend along the base mesh.
I have tried the Curve modified but it also changes the shape.
Even tried the Lattice modifier to match the base shape as well as I can but still there is slight stretching which I do not want.
Is there a better way to go about doing this?
Any help is appreciated.

I'm afraid this isn't possible with modifiers. Even the cast modifier using a shere doesn't succeed in keeping the ratio between the cells. The difference between the flat surface and the egg is too big. You can try baking the cells as a normal map and counter distortions with a tweak in the UV unwrap.

Ok, thank you.
The base mesh will be deleted later and only the hexagonal shapes will remain. Baking the normal map and achieving the same with UV unwrap is not an option for this project.
Any other work around or software that might help with this?


text:
How can I retain original dimensions after adding thickness?
After scaling (3D prep), the clean object (0 NonMan) has the dimensions as expected:

When applying solidify modifier with thickness 1mm, the entire object (lid) is scaled up:

Original sizing (close to) is retained with thickness 0.05mm, however this would not be reasonable since I need some minimal structural strength.
Is there a clean way to retain the original geometry without rescaling everything?

try changing the offset value

@Chebhou That did it (offset 1), thank you. Also found out that, flipping normals on the top part added thickness inside rather than outside, in order to keep the original size.

Yes, that generally means the normals were inverted. You could use the offset value to control the direction of the solidify, but I guess fixing the normals is the best way.


text:
cycle renderer with multiple textures on single mesh
I have a mesh body, an avatar,  with a  skin texture and a shirt texture on top of the shirt.  Using blender renderer it works perfectly, Using cycles it does not.  the skin texture is fed into one input of a mix shader, the other input gets the shirt texture with one link to the color input and the other to the alpha input.
When I hi-light image texture input with the skin the shirt dissapears completely,  when I hi-light the shirt input the shirt appears and the skin turns black.
Here is a link to the blend file
 http://pasteall.org/blend/index.php?id=50999
The "standard" answer says plug one texture into one input of mix shader, the other texture,the shirt into the other and the alpha of the  shirt into the alpha input on the mix shader.  Does not work :(
I've seen this question posted before and the answers don't work for me.
Following is screen capture showing shaders and render viewport.

I'm using Blender v2.79.6 from 2019-01-14.
Halp :)

I finally figured out how to get multiple textures on a single material. In the image I show a skin texture overlaid with a shirt texture. The shirt has transparent component allowing one to see the skin below.

Hello Vince, please provide more explanation on how you solved the problem

the image should explain it.  In the  original I was feeding the mix shader directly into the material output.  In the image above you see I added a diffuse shader.  I just tried the above layout with blender 2.79.7 and it still acts strangely.  If setup as above when I left click on the skin input text shader, the shirt disapears and all I see is skin.  If I click on the text input ( starlight_upper.png in above ) then the shirt ( see above for image of the shirt ) appears and the skin turns black. in 2.79 I've tried both the mix shader and the color mix shader.  Same results. That help?

You have quite a few problems here, you should probably watch some basic cycles material tutorials. You appear to have misread some stuff about alpha blending, it is not how you would achieve what you are trying to do.
The way to do this would be to assign one material to the shirt (using the shirt texture) and a whole different material to the skin. As they are separate meshes this should be fairly easily.
Another problem I have noticed is that you are plugging colour data (the yellow node connections) into shader data (the green ones). While cycles will try and make sense of this, generally if you are plugging connections between different coloured sockets, then something isn't quite right. In this case you want the put a shader node (Like a diffuse BSDF) in between the texture and the mix shader or output(if you get rid of the mix shader).

The mesh is from a product to support SecondLife(SL) and does not support cycles. I'm trying to figure out how to migrate to cycles eg. Blender 3.80 with minimal impact.  The shirt and skin are supplied as textures only.   Normally one would be able to add undershirt, shirt, jacket etc as another texture layer.  Important when one uses this model for creating a new undershirt,shirt,jacket.   There is a jpg template for making one's own undershirt,shirt,jacket that is applied as a texture only in SL. So seperate material would not work at all.

I forgot to mention that the upper body is all a single material, and the shirt and skin are both textures that are added.  Blender 2.79b and 2.97.7 still don't work, while 2.80 does.


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How to change file export numeration?
I'm exporting each frame of my animation as an obj with the animation export option.
Blender automatically outputs all the numerated files however it adds 0s before the numbers.
Example:
run_000001.obj
run_000002.obj
...
run_000522.obj
I cannot find any setting to remove the 0s, I'd like for it to export them:
run_1.obj
run_2.obj
...
run_522.obj

refining the answer from @user2816
Just use a single # eg //renders/#.png to render files with no zero padding, eg. 0.png, 10.png, 100.png
There's no need to render several frame intervals for different number lengths.
Tested in Blender 3.4


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how would i rotate an angle Torus
Hi how would i  go by rotate an angle Torus at 45* to revolve around the origin like in gif 1 and not like gif2 ? I would like to do something simulator to this video  thank for your help

https://www.youtube.com/watch?v=ZhyT6yUxZq0

In both of the gifs, your Torus is rotating. Do as Mr Zak suggested and edit your post better explaining what you need/want. Until then few people can help you.

In gif1 you are rotating on z-axis by pressing RZ - in gif2 you are rotating on y-axis by pressing RY.


text:
Can someone make a plugin for .nif like 3ds max has
One of the biggest reasons people who mod games (and there are thousands of people) use 3DS Max is because of the ".nif plugin". Blender use to support this import/ export, but for some reason they dropped it. My Question is.... Can someone PLEASE make a plugin to Import/Export .nif files for Blender. I guarantee Blender's user base would grow by over 10,000 people.

I'm voting to close this question as off-topic because it's a feature request not a question.

This seems to be a feature request, not a question about Blender.
You can't "guarantee" any "user base growth", nor is that a valid goal. There is no direct benefit in that for whoever would bother making such plugin.
You could either try hired development if you are interested enough to invest some money in it, or request that in a forum like Blender Artists.
Also a little google search yield this that may be of interest:

http://niftools.sourceforge.net/wiki/Blender
https://github.com/niftools/blender_nif_plugin


text:
Do Animation curves have some stored offset? Blender 2.79
I have an odd problem. I am exporting a scene, including animation curves.  I have parent/child relationsships in my scene.
Base example:
I create a big cube at the origin.  I add a small green cube as a child of the big cube, offset z +2.  I hit I to create a location keyframe.  On a later frame, I shift the green cube 2 in the x axis, and take another location keyframe.  And later again, I move it -2 on the x axis, and take another location keyframe.
Here is the result:

The graph shows exactly what I would expect: the X position of the green cube goes from 0 to 2 to 0.
However, let's repeat the process, except starting with the big gray cube at offset 4.
Create a cube at 4x,0y,0z.  Add a red cube at 4x,0y,2z, and make it a child object of the cube.
Create the same location keyframes: frame 0, x = 4.  frame 30, x=6. frame 60, x = 4.

So this shows the X Location in the curve as starting at 4, going to 6, and back to 4.  This is not what I am expecting!  Because the parent object is already at 4x, I was expecting the child object to go from 0x to 2x to 0x.
Now here's the fun part:  Let's say I move the gray cube back to 0,0,0.  Unexpectedly (to me at least), the red cube's curve stays at 4 to 6 to 4!  In the scene, the red cube is moving from 0 to 2 to 0, but the curve says otherwise! Clearly there is some sort of offset saved in the curve!
So, my exported scene gets all messed up unless I happen to position my parent object at the origin before I start taking keyframes, which really is not practical.
For what it's worth, here is my code to export the animation curves:
scene = bpy.data.scenes['Scene']
fps = scene.render.fps
# Export actions that match the format "[name1]name2"
pattern = re.compile('\[([^\]]+)\](.+)')
actions = bpy.data.actions
fw('<animdata>\n')
for actionname in actions.keys():
    match = pattern.match(actionname)
    # Does the action match [name1]name2 ?
    if (match == None):
        continue
    action = actions[actionname]
    # Grab the [name1] portion of the action's name as the object name
    obname = match.group(1)
    # Grab the name2 portion of the action's name as the Action name
    shortname = match.group(2)

    fw('  <animation name="%s" fps="%d" start="%d" end="%d">\n' % (shortname, fps, scene.frame_start, scene.frame_end))

    # Grab the curves of this action.
    fcurves = action.fcurves
    if (len(fcurves) > 0):
        fw('    <anim object="%s">\n' % obname)
        # Write out each curve as a <curve> element
        for curve in fcurves:
            fw('      <curve path="%s" axis="%d">\n' % (curve.data_path, curve.array_index))
            for kp in curve.keyframe_points:
                fw('        <point interp="%s" co="%f,%f" lh="%f,%f" rh="%f,%f"/>\n' % (kp.interpolation, kp.co.x, kp.co.y, kp.handle_left.x, kp.handle_left.y, kp.handle_right.x, kp.handle_right.y))
            fw('      </curve>\n')
        fw('    </anim>\n')
    fw('  </animation>\n')
fw('</animdata>\n')

Thanks for any insight!

Related https://blender.stackexchange.com/questions/169416/does-a-child-object-inherit-the-matrix-from-the-parent   or as shown in the issue here https://blender.stackexchange.com/questions/214740/two-objects-right-next-to-each-other-but-wildly-different-coordinates   that when an object is parented "defaultly" the matrix parent inverse is set  such that the matrix local at that location is unity.  Options here would be to clear the parent inverse https://blender.stackexchange.com/questions/28896/how-to-clear-parent-inverse-without-actually-moving-the-object  or get into habit of using parent

without inverse.  Or adjust exported fcurves according  the matrix parent inverse translation.

Thanks, @batFINGER !


text:
Is (or will there be) there a Blender-based GUI library, like GTK (based on GIMP)?
Since Blender's GUI has so different approach to the whole area You see on the screen, I'm wondering about programming software that has a GUI based on that of Blender.
For many applications (where You have to keep an eye on many aspect at the same time) this would offer a much better approach than conventional GUI libraries.
Obviously there isn't such a project. Why?

I think there's no such thing, now, but since years Ton (blender creator and still current leader) wants a "simplified ui" version of blender targeted to children and/or less experienced users, codenamed "101": that could (arguably) mean that a "pluggable" interface engine is needed... if that happens, there could be a chance to get what you mean above, imho.

Quite interesting, since Blender's UI is quite unique and very flexible.


text:
Remove doubles corrupts vertex groups
When I use 'Remove doubles' on my weight painted mesh it will mess up the vertex group selection:
Before doubles removed:

After:

Somebody knows a solution for this ?

"Somebody knows a solution for this?" Yes, redefine your vertex groups. Vertex were eliminated by removing doubles, you can't possibly expect vertex groups to remain untouched.

Is there any wax to select a vertex group with the invisible vertices (what is wasn't applied to te vertex group) automatically ? so I can fix the whole thing


text:
How can I instant delete all of the actions ?
I need the clean my blend file from the actions, but if I delete them in the dope sheet it doesn't work.

Every animation that is not used by any object and that is not F (fake user, which means that doesn't need to have any user to be saved) won't be saved when you'll close and reopen your file.
Now, to delete an action that is currently used, go in the Dopesheet / Action Editor mode, and press shift and the X on the right of the name of the animation. When you'll reopen the file the animation won't be here anymore.
To delete a F (fake user) animation, disable the F, and same thing: press shift and the X and reopen the file.
If an animation isn't assigned to any object anymore, you can go to the Outliner, select Orphan Data in the dropdown menu, you'll see all the orphan animations, select them all and right click > Delete. Even the F animations will be deleted.
If you only want to delete the visible animations, you can select all your objects, press the Spacebar and type "Remove Animation", You can also go into the Outliner, type "Animation" in the Search box, select all the animations and right click > Clear Animation Data.

great then, i've edited it several times to add some precisions, so perhaps read it again  ;)


text:
Join objects which using the same material
I have 117 objects and I tried to connect them into one object and separate by material, but it didn't worked because blender separates the objects which have duplicated materials too (material.001, material.002 etc.). How can I join these objects ?

Could You clarify the question a bit? What exactly do You want to achieve? One mesh containing 117 objects, and every one of them must have different material or one mesh with single material or something else?

Hi Mzidare, some of my objects are using the same material, I just want to connect them, but how ?  ( I can do this manually but it will take a lot of time because I have 117 objects)

If You wanna to connect all objects using the same material, go to Select>Linked>Material. This way You will select all objects sharing the same material. Then CTRL+J to join them.

But when I click on the "Select>Linked>Material" it will not select them because of the annoying .000 thing on every material.

Ok, so we're clear on that. It's not the same material, but different materials with the same settings. Then maybe those objects have similar names, different then other objects. If so, deselect all, go to Select>Select Pattern, then write shared part of the name before * and uncheck Extend. Then press ENTER

No, they haven't, each object has different name. Any solution ?  Maybe select objects which using the same texture ? Thank you that you trying to help anyway.

Sure. If they have the same texture, then select one of them and go to Select>Linked>Texture

Doesn't working, because blender puts .001 to the same textures too -.- "col_dirt.jpg.001" this is very annoying

Help me somebody please !

Fear not my friend. Here I come with help for You :) You have to open text editor in Blender, click New to create new text file, and paste this code snippet (below), then change "somename" to the materials name before .001 (f.ex. if it's Material, Material.001 and so on, You have to write Material there). Then press Run Script and watch the magic (it should select all objects having material with this name part).Important is to keep indentations cause Python is very sensitive about it, so in line 1 and 2 there is no indentation line 3 - 4 spaces, line 5 - 8 spaces, line 6 - 12 spaces.
import bpy
scene = bpy.context.scene
for ob in scene.objects:
    for slot in ob.material_slots:
        if ("somename" in slot.name):
            ob.select = True


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Attempting to convert a model with "bones" - how to find the coordinates of each rotation point?
I should explain that I've only just downloaded and installed blender maybe a week ago? There is a model I am going to use for a project and I have to convert it to a special format for the engine I'm using. It doesn't support bones or any rigging. To actually do rigging I apply a transformation to the drawing space according to where the model should be (for instance, move a submodel so that its rotation point is at the origin, rotate, and then move back and then do whatever transformations were applied to higher models in the hierarchy). So I do have the models themselves (the geometry and textures) converted into the proper format. That I do not need help with. I have another program for that but it only views polygon data (for the same reasons as above). I'm trying to determine those "rotation points" in blender. I have no idea how to use the interface. I figured out how to load the model in the window last night and I managed to delete some stupid cube that was sitting in the default window. I'm essentially wanting to know what menu or what button (preferably with screenshots) I go to in order to step through all the rotation points one by one so that I can convert it to my setup?
It is quite possible that my setup is slightly different than how bones work. I apologize if so. It's how I've thought about for quite some time when dealing with models. Hopefully it isn't too confusing for you people who have used Blender for more than a few hours.

For those asking what engine I'm using. It is game maker 8.0 pro. Yes I have read the manual thoroughly. It does not support bones. No, I cannot convert the codebase to something else as it is literally years old. No, I would prefer to not use a 3rd party library to load in the original model with its default rigging.

I understand that the SE new ToS and whatnot put "New Contributor" on people for some reason. I specifically do not like this for the reason that I am NOT a new user of stack exchange and do not need to be treated differently simply because I posted on a subforum I haven't before. Thank you. I just wanted to get that out of the way before I get inundated with "welcome to __" posts. I do not like those.....

Can you add a screenshot what you get in Blender? Do you get an armature imported (looks like this, press Z to see in wireframe to check if it's not hidden inside the mesh) or is your model a collection of parts with unique origins? You might also got the "bones" as just empty objects..

@JaroslavJerrynoNovotny I have the armature. I would prefer not to post a screenshot of the model if that is acceptable. I mostly just have no idea what menu to go to that would show the coordinates of this armature.

With the armature selected switch to Edit Mode, select the bone you want, and the location of the point it rotates around is displayed in the Properties panel (N) under Head:

To automate this open a Text Editor window and run this code:
import bpy

obj = bpy.context.active_object

if obj.mode is not 'OBJECT': bpy.ops.object.set_object_mode()

for bone in obj.data.bones:
    print("Bone: {0} origin is at {1}".format(bone.name, bone.head))

It will output into System Console. You can rewrite it to output to a file in a custom format your engine will understand.
The values will be relative to the armature centre of origin and with Z axis pointing up.

Unfortunately my engine requires it to be hardcoded in manually (and quite tediously) but thanks for the tidbit about automating it.

Alrighty I have confirmed that this works (or rather that i could follow the steps). Unfortunately my other program put the model in a different pose for some reason but luckily blender seems capable of saving each submodel separately. However a little linear algebra never killed anyone and it should be fun.


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I want to get the texture filename of every triangle in the scene and put them into a format to be exported for an add on script
I want to write an add-on script for a custom format. I have 99% of the boilerplate by finding a similar format's export and modifying it heavily.
Here is a snippet from my current script.
    #open the file for writing
    file = open(filepath, "wb")

    #get script name from the filepath - may want to check if this is blank at some point int he future?
    base_name = os.path.basename(filepath)
    script_name = os.path.splitext(base_name)[0]

    #branch the output here, depending on what the user wants to export
    #model output
    model_output_string = '';
    model_type_num = 4;
    vert_count = 0;
    #build the model into a string, then write that to the file later
    #start writing the mesh data to the file
    model_type_num = 4;
    if len(mesh.uv_textures) > 0:
    #if the model has a UV map
            uv_layer = mesh.tessface_uv_textures.active
            for face in mesh.tessfaces:
                    faceUV = uv_layer.data[face.index]
                    i=0
                    for index in face.vertices:
                            if len(face.vertices) == 3:
                                    vert = mesh.vertices[index]
                                    model_output_string += '%s     %s     %s     ' % (integer_to_string(vert.co.x), integer_to_string(vert.co.y), integer_to_string(vert.co.z))
                                    model_output_string += '%s     %s\n' % (integer_to_string(faceUV.uv[i][0]), integer_to_string(1-faceUV.uv[i][1]))
                                    vert_count+=1
                                    i+=1
    else:
    #else if the model has no UV map
            uv_layer = mesh.tessface_uv_textures.active
            for face in mesh.tessfaces:
                    for index in face.vertices:
                            if len(face.vertices) == 3:
                                    vert = mesh.vertices[index]
                                    model_output_string += '%s     %s     %s     ' % (integer_to_string(vert.co.x), integer_to_string(vert.co.y), integer_to_string(vert.co.z))
                                    model_output_string += ';     ;\n'
                                    vert_count+=1
    writeString(file, str(vert_count) + '\n')
    writeString(file, model_output_string)
    #end the model output
    #output the file and close it for editing
    file.flush()
    file.close()

Currently it takes every triangle in the scene and generates a file with the following format:
<number of triangles>
<triangle1.vertex1.x> <triangle1.vertex1.y> <triangle1.vertex1.z> <triangle1.vertex1.u> <triangle1.vertex1.v>
<triangle1.vertex2.x> <triangle1.vertex2.y> <triangle1.vertex2.z> <triangle1.vertex2.u> <triangle1.vertex2.v>
<triangle1.vertex3.x> <triangle1.vertex3.y> <triangle1.vertex3.z> <triangle1.vertex3.u> <triangle1.vertex3.v>
.
.
.
<triangleN.vertexN.x> <triangleN.vertexN.y> <triangleN.vertexN.z> <triangleN.vertexN.z> <triangleN.vertexN.v>

This part works fine. The issue is that I also need to save the texture data as well.
Each triangle has a texture, at least, assuming the model being saved is textured. We'll go under the assumption that the models are textured when being saved. It will make my work easier. The format I want to save it in is of the following format. The format dictates the need for two files.
The geometry file:
<number of triangles>
<number of texture batches>
<triangles within batch 1> <texture id of batch 1>
<triangles within batch 2> <texture id of batch 2>
.
.
.
<triangles within batch N> <texture id of batch N>
<triangle1.vertex1.x> <triangle1.vertex1.y> <triangle1.vertex1.z> <triangle1.vertex1.u> <triangle1.vertex1.v>
<triangle1.vertex2.x> <triangle1.vertex2.y> <triangle1.vertex2.z> <triangle1.vertex2.u> <triangle1.vertex2.v>
<triangle1.vertex3.x> <triangle1.vertex3.y> <triangle1.vertex3.z> <triangle1.vertex3.u> <triangle1.vertex3.v>
.
.
.
<triangleN.vertexN.x> <triangleN.vertexN.y> <triangleN.vertexN.z> <triangleN.vertexN.z> <triangleN.vertexN.v>

The texture file:
<number of textures>
<texture filename 1>
<texture filename 2>
.
.
.
<texture filename N>

I have no clue on how to get the filename of the texture for each triangle. What I would like is to be able to take each triangle as I iterate through them and put the filename of the texture associated with that triangle into an array. I can then take that array myself and make sure none of the texture ids are duplicated and that any sequential faces with the same texture get into the same branch. A later "upgrade" might be to take the triangles and sort them into batches so that no texture id is recycled, but that can also be done in the program they are being loaded into (and it would be way easier at that end then in the python model exporter).
I keep hearing something about texture slots material, but honestly I have no clue what that means at all other than that in computer graphics the material dictates data regarding the physical roughness and smoothness of some surface (aka polygon aka triangle). I do not need anything from the material other than the filename, so a solution that does not make it convenient to go back and add other properties to this export is perfectly acceptable. There will not be any support added later for more material stuff. The software this is being loaded into does not support such data, PERIOD.
For those wondering I'm on blender v2.79 as reported by the software. If a convenient solution requires an upgrade, that is perfectly acceptable. I am only on 2.79 because I don't use blender really at all and I just haven't yet bothered to go download the new version to get feature upgrades I'll probably never use.
I've also heard that supposedly this code does not grab everything in the scene. I'm not familiar enough to know whether this is the case or not. If this is the case please let know in the comments. I can make a separate question to look into getting that corrected (assuming I can't fix it myself).

@brockmann But the file format has zero relevance at all??? I only want to know how to access whatever texture corresponds to each face or mesh or whatever textures are applied to...

So I wrote that comment after waking up in the middle and choosing to check this site. The hilarious result occurred then of me having a wacky dream where this post got closed and three answers it received deleted due to me posting this page once in a discord thread and it then getting closed for reason of “spam”. Because apparently sharing in an external site once counts as an egregious offense. I felt like sharing this since it too weird to pass up. Please don’t vote to close as spam. XD

Have you looked at the inside of a .obj file (and corresponding .mtl file)?  It's almost exactly like the format you've described here, just with xyz on separate lines from uv.  The texture filenames are in "materials", and materials are assigned to faces.

@emackey I have seen obj files somewhat, but I’m not sure what good one would do here. There’s definitely no stipulation in my situation at least that anything I’m loading into Blender is in an obj format to start with. Is there any way to view the obj export source code like on a github somewhere? If so, someone explaining how in the world blender is generating the obj material file might work as an answer.

@emackey I think the script that the asker attempted here might be able to get me a clue as to how to do what I desire. The more trivial problem now is that I don't know how to run their script file. Do you happen to know by any chance? https://blender.stackexchange.com/questions/80773/how-to-get-the-name-of-image-of-image-texture-with-python

Copy those text in to script text-block and hit run

There is no such a single file for material in Blender. Material is assigned to face for sure. And Material may contain diffuse color texture and other texture if present.
In the list object.data.polygons, you should find an entry for material index call face.material_index. Then you will need to find what texture you want to export to the file. Again, Blender and all other 3D software use their own format to manage the material. You will need to write your own converter to make it possible to export to file or text in your case.
Also, a similar github project to export obj can be found here

I go into blender. I have a cube. I select it. I go to uv edit on the bottom pane. I change to edit mode on the cube. I drag a texture into the white box that appears. The cube now has a texture. How do I access this via code? There is no material_slot. Blender claims there are 0 material slots??? And surely Blender has a default way of storing the data internally.

I suspect I'm not doing something properly in my usage of blender. I may need to edit my question to explain how I'm using it better.

@TheGreatDuck https://blender.stackexchange.com/questions/75816/how-to-distinguish-material-and-material-slot

Interestingly enough, if I take whatever model I'm interested in and export to obj and then successfully import it back in the script I'm about to post here works. This does imply that there's something I could do to improve stuff, but it will at least work for the moment. I'm still going to accept your answer (unless even better appears) since you are definitely correct that blender can and will use different material storage classes depending on exactly what you are doing - clearly the weird situation with the obj export I just mentioned is evidence enough of that on its own.

Enjoy the bounty. You've earned it!

What I have determined is that even within my own editing process there is definitively no single answer on where to get the texture.
There are two means by which texture data is being supplied to any models I might be viewing or editing or what-have-you. The first method is that I directly drag and drop an image file into the uv editing window with a mesh selected. For whatever reason I cannot locate the exact mechanism by which the texture is then accessible to other scripts such as the obj export (which can and does export the texture filename into its material file). This is acceptable, because the obj export works with it.
The other method is to load an obj file with a material file attached to it. With the obj file loaded in the following script appears to print the texture filename for every triangle in the scene. I tested with 5-6 obj models both from me exporting a mesh made by me via dragging and dropping textures and from me loading old obj files I have received from other people.
import bpy

texture_list = []
for obj in bpy.context.scene.objects:
    if obj.type == 'MESH':
        for f in obj.data.polygons:
            mat = obj.material_slots[f.material_index].material
            # Iterate over all the current material's texture slots
            for t in mat.texture_slots:
                # If this is an image texture, with an active image append its name to the list
                if t and t.texture.type == 'IMAGE' and t.texture.image:
                    texture_list.append( t.texture.image.name )
print(texture_list)
print(len(texture_list))

The script above is an amalgam of the scripts given in the answers to this question:
How to get the name of image of "Image Texture" with python?
I wouldn't say I wouldn't say I understand fully how my script works. Basically I took the component of the one (accepted answer's) script of "loop through the objects face data" and merged it with the other script's component of compatible material examination.
This can in turn be restructured to be merged with my scripts current loop. I might post an update later to show the completed thing, but the actual difficulty of "how in the world do I get the texture data?!?!" has been resolved - architectural organization/integration of code is trivial.
I will not be accepting this answer though as it definitely leaves a bad taste in my mouth. I definitely do not like the idea of obj model export somehow working where mine fails and me having to try and accommodate for this, but it is at least viable enough to be worth sharing with anyone having similar pains. I don't condone hacks, but at least this works...


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How to save each individual "object" in an obj file as separate obj files?
I've been importing some somewhat complicated obj files for a project. I noticed that these models had different segments that would end with a line starting with 'o' followed by some name for that segment (I'm assuming 'o' stands for 'object'). The format I'm converting these obj models to is incredibly niche. It's a custom model format and afaik only one obj converter exists. All it can do is take the entire obj file as a single model with a single universal texture and convert it to other format which quite literally only contains a list of triangles as raw data.
This has produced an unusual issue for me. I have been forced (by my own insistence to not waste more time coding my own converter) multiple times now to hand-edit these obj models as a result of the model format. I'd have to copy the obj files X times according to however many internal objects there are and then hand delete the face elements corresponding to that object via a text editor.
Preferably it would be nice to just open a model and then click "save as individual pieces" or click save on each object if there is some spot in the editor that they are listed. Does Blender have such a feature? I've only ever used it to convert a few models to the obj format as the other converter didn't support those formats.

You can "Separate Loose Parts" in Edit mode and then use "Selection Only" in the .obj export options.

@rob going to need a bit more specifics on location in the gui then that.

Somewhat related https://blender.stackexchange.com/questions/130841/exporting-only-1-object-at-a-time-to-stl-using-blender-script-python using obj export ofcourse.

I created a quick scene with a few basic Meshes Joined together to form a single Mesh

In Edit mode I selected everything and pressed P to bring up the Separation menu and selected "By loose parts"

Now in Object mode you can see even the over lapping components are separate Meshes.

From the File->Export menu select Wavefront (.obj)

And check "Selection Only"

I did not look into it, but you may be able to use Python to select each Mesh in turn and call the Export module in a loop.

So is each mesh what the different segments of the obj file are defining? (I might be a bit too far in the low level implementation of the obj file. I only know the pieces by actually reading the file in a text editor.)

at this point I would just say, give it go. If all the vertices are linked together then they can not be separated without manual intervention, but most likely they are grouped together but are not attached together.


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Divide a face into multiple vertical edges
Blender newb here. I want to divide a face into multiple faces (vertical edges).
From:

To:

Naturally, I can use the Knife tool and do it manually, but if I have many divisions to create this seems highly inefficient.
For the picture I subdivided and simply deleted each horizontal edge between the desired edges, but this is also absurd.
This seems very simple but nothing related has come up in my searches.
Thank you!

Use Ctrlr to make "loop cuts." Hover over one of the horizontal edges and you'll see a purple preview of the cuts. Scroll up with the mouse wheel (or press the up arrow) to increase the number of cuts. Scroll down with the mouse wheel (or press the down arrow) to decrease the number of cuts. Left-click or press enter to confirm the cuts.
"Loop cut" will normally cut as far across as it can. If you want to avoid cutting the upper poly, hide it first (select and press h), make the cuts, then unhide (press alth to unhide everything).

that will cut the other face too, to avoid that hide other faces

This will give you more control than subdividing. When you subdivide, the result has to be 1, 3, 7, 15, 31, 63, etc cuts. With "loop cut" you can make an arbitrary number of cuts.

Well, subdivision does that too :-P There are only two ways it can go down. You either have an n-gon, or you have triangles. Both will produce triangles if the upper is NOT hidden. Both will produce an n-gon if it IS hidden.

You mentioned if you subdivide it has to be 1,3,7 etc. but I am able to choose any number for the divisions. I must be missing something.

Yes, you can subdivide any number of times you want. Subdividing once gives you 1 cut. Subdividing again gives you 3 cuts. Subdividing again gives you 7 cuts. Try using "Subdivide" to make 10 cuts without changing the selection and I think you'll see what I mean.

For this case I offer an alternative method using Subdivide on selected top and bottom edges of polygons you want to cut vertically. Sometimes it can be quicker than hiding & unhiding rest of the mesh when using loopcuts method ...

...and I think it is the only working method to quickly cut more than one polygon.

Just a tip - if you want to quickly deal with the resulted ngon, select the face and press CTRLT to triangulate it.

saved my life, great method!

I figured it out.
Ctrl+Tab to select Edge mode.
Select the two horizontal edges and choose to Subdivide under Mesh tools. Number of Cuts will dictate the vertical edges.

I had no idea where the mesh tools are so just selected the edges and hit F3 and searched for Subdivide


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Triangle artifacts in cycles render with material
I have used the same camera, world and material for renders with a previous, similarly-modeled mesh.  The renders had no artifacts. All faces, curves, interior of the holes etc were smooth.
But when I try the same camera, world and material with my current mesh, this is the result.

I started each of these with an SVG curve of the profile of the item, converting it to a mesh and extruding it to the appropriate Z height.  However, I think with the successful model, I had first subdivided the mesh into quads after converting from a curve.  I forgot this step with the pictured mesh above, and have tried to clean up as best I can.
Any suggestions for how to clean this up without having to just start over?

Can you upload your .blend file to http://blend-exchange.giantcowfilms.com ?

Your mesh seems to have very large NGons, and an uneven topology with very dense areas with lots of very small polygons that then cause lots of thin and long triangles on the larger faces. That is possibly what is causing those artifacts but it's hard to tell without a closer looking at the file. Could you post a link to the Blend file? You may also try recalculating normals and removing doubles to see if it helps somehwat

Sorry, probably should have mentioned that I don't feel I'd be cleared to share the .blend file for this. The ngon issue makes sense. I did try removing doubles and recalculating normals a few times while finding holes in the mesh along the way.

Thanks for taking a look. With the cleanup required, I might save time just starting with a new profile curve->mesh with better quads before extruding.

Yeah, I started some cleanup on the existing mesh guided with your suggestions, and the renders were getting better.  But there were so many that I just opted to go with starting again and extruding off a better mesh profile.  Removed, optimized some vertices on the curve, converted to mesh then split into quads.
Checking renders as I go, punching the holes with booleans, and it's going much quicker, no cleanup required.  Thanks a million!


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What s wrong with the polygons of my model
why are all those polygons transparent in my model?

Probably your faces normals : in edit mode, select all and Ctrl+N. But hard to see well in this front ortho view. You should share your blend file in order to check what is wrong. Use http://blend-exchange.giantcowfilms.com/

What has happened is the normals on you faces have flipped.  This will sometimes happen when you scale a mesh negatively or you extrude a face in a negative direction local to the face.  One way to see these faces is by disabling backface culling.  But I would not recommend this, because all it does is makes both sides of the faces visible in the viewport.  When you render you will still get dark looking faces.  For a permanent fix, go into Edit Mode, press A to select all faces.  Then select recalculate normals under Shading/UVs in the tool bar, or just press CTRL+N


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merge object with another that uses mirror modifier
I want to merge 2 objects using Ctrl+J but one of them has a mirror modifier, and I don't want it for the other object. How can I do that?

You want to merge 2 faces ? Or to join 2 objects (that's what is done with Ctrl+J) ?


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Looking for a usable solution for Z-pass aliasing
i'm trying to render a small video of a city in fog using the cycles engine. The main problem is, i need physically accurate fog. In order to achieve that i'm using the distance of a pixel from the camera to the object calculated by the Z-Pass. But the Z-Pass has no anti aliasing so the end result has a lot of jagged edges. I have already searched for a solution.
The options were:

Switch to blender internal render because it has FSAA (Full Sample Anti Aliasing)
I have tried that and the option does what i need, but i started using cycles and switching to blender internal render
at this stage requires a lot of material work to be redone.
Use super sampling and down scale after the rendering.
This does work but has some side effects. In order to achieve good results i need to render 16 times more Pixels.
In theory i can also reduce the rendering samples per pixel by that factor, so the workload should stay the same.
But it doesn't, this correlation is not linear. It takes considerable more time to render the bigger picture.
5120 x 4096 with 9 samples takes 4m53s and a 1280 x 1024 px frame with 144 samples takes just 3m39s. Which doesn't sound like a lot, but if you need 2400 frames, it does add up.
Also the super sampled result has a lot more noise and is noticeably darker as well.
Use mist pass.
Sadly, i had no success extracting the distance information from the mist pass and wasn't able to get it to work
in my application.

Does anyone have any suggestions?

Use this shader as an override for all your materials in Render layers and render a perfect Z-depth pass that is pixel-perfect anti-aliased like your final render:

It shades the geometry based on distance from camera and renders fast (only 1 emission shader, you can omit the black emission).
It is basically similar to the mist past, but let's you do more magic for example with transparency if you need.

Can you give a little information about what causes the problem and how that other answer solves it? This is basically a "link-only answer" so far.

My simple solution based on https://blender.stackexchange.com/a/53003/26896 answer.

I remember having this problem. It actually brought our project to a halt :-( I wish I'd seen this fix before. From BlenderArtists RamboBaby says:

Yes, enable the "Save Buffers" option on the Output tab (F10) then enable the button that appears next to it labeled "FullSample". Any time you change the values of any nodes the render result will default back to the first sample of the FSA buffer sequence so you'll need to SHIFT+R ("Read saved FullSample Layers") with your cursor hovering in the nodes window in order to see the result updated as a smooth antialiased pass.

This is very old information and you should verify it, because it does not work today.

:-( I thought it mentioned a current version of Blender, but I must have imagined that...


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Constrain armature movement based on child bone position
Fair warning: I'm new to rigging.
I am working on a snake-like creature's rig and have organized the bone hierarchy like so:

Basically the head bone is the parent of the neck, the neck is the parent to the next bone in the chain, etc.
I have successfully made this clip (albeit painstakingly):

Now I am trying to make an attack clip but the interpolation causes the tail to dip below the XY plane:

Is there a bone constraint that will prevent the armature from dipping below the XY plane? Could I have rigged it with some kind of IKs or a different bone hierarchy?
Any guidance or suggestions are greatly appreciated!

Try Spline IK constraint. It almost does what you want. But it is hard to simulate the snake swing natually. Once upon a time there was an unofficial Spring constraint commit, which does work in this case. You may want to take a look.

To get a curved armature result, the splineIK constraint is very helpful. It allows you to use a curve object that the armature follows. You may also want to try using curved bones, which you need to enable B-Bone display for the armature.
As the curve defines the "shape" of the bones you animate the curve to move the armature. To achieve this go into edit mode for the curve and for each control point add a hook by pressing ⎈ CtrlH->Hook to new object which will create an empty for the point. Now when you animate the position of the empty, the corresponding point in the curve will follow and the armature will bend to match.
For the animation you are trying to do I would reverse the direction of the armature. I'm not sure if this will make the rest of your animation easier or not.

Here is an example with curved bones enabled

I think this will work very well for me. Thanks so much for the insight and the effort to create an example file. I think having the bones reversed should also help me.

follow up question: how do you place keyframes for the locations of the empties?

Same as any object or bone, select and press I and choose what to keyframe or enable auto keyframing

Thanks again @sambler. With your help I was able to accomplish what I set out to do. The last little step I did was create non-deform bones in the armature at each Empty and then parented the empties to those respective bones. This way I could keyframe just bones in the armature instead of keyframing the Empty positions in edit/object modes.

Ah, the tentacle rig. I've also heard "rope rig." One of the more complex rigging challenges. Semi-relevant: check out this promo video for the Octopus character in pixar's upcoming Finding Dory. Very complex tentacle setup!
I'm no rigger, but you might find some useful info by looking into solutions that others have posted online. Those are not Blender-specific, but there seem to be some blender tutorials too that could get you started. Apparently I need more reputation points to post more than two links, but I found several on YouTube!

Hi. Welcome to BSE! Instead of just posting links, you might want to consider editing your post and adding some description instead of just posting links. Links are good for now, but they can go down and people should be able to learn from your answer for years into the future. Thanks for considering, Shady Puck.

That's an awesome video about the octopus, thanks for that! Also thanks for giving me some results to go through. A lot of it was knowing what terms to search for.


text:
Can you auto-pack a selected group of islands in UV view?
I'm trying to figure out ways of optimizing my UV Layout creation workflow. Here's what I do so far:

mark seams on the mesh
select the mesh and press u u to auto unwrap it
if the UVMap image ("checkers" view) looks too distorted on the mesh, go back to step 1 (mark more seams).
Once satisfied, select the logical parts of the mesh in 3D View so only those corresponding islands show in the UV view. Due to auto-unwrap, these islands are dispersed throughout the UV layout.
Move each of these islands one-by-one close to each other so they are all in the same location in the UV layout
Repeat steps 5/6 for every part of the mesh

Is there an easier way to do step 5? Like some kind of command in UV mode like "auto-pack the selected islands" using the same underlying layout algorithm used for the initial unwrapping?
Also, if there are any tricks worth knowing that could speed up this process, please let me know! Thanks.

I'm not sure what is "dispersed throughout UV layout".. but you can pack selected islands by Ctrl+P. Also it's not clear whether you want to stack islands on top of each other or to place them next to each other.

Ah yes, ctrl+p was exactly what I was looking for, thanks for that! By "dispersed throughout" I meant that when you first unwrap the entire mesh and blender places all pieces arbitrarily in the UV layout. Leave an answer with the Pack Islands command and I'll mark it accepted.

Related - http://blender.stackexchange.com/questions/39580/what-is-the-best-way-to-scale-uvs-to-fit-an-image

Use Pack Islands command to automatically organize all your islands so that they fill the UV space:

The Pack Islands tool will uniformly scale, then individually transform each Island so that they fill up the UV space as much as possible.


text:
How do you snap the camera to view in Ubuntu
I know in Windows it's Ctr + Alt + Numpad 0. However, in Ubuntu that minimizes the window. Does anybody know how to snap the camera to view in Ubuntu?

You could just change the controls in the User Preferences.


text:
GPU Compute (CUDA) Frequently Crashes Computer
I've run into a rather irritating issue when dealing with a somewhat computationally complicated scene (attached below) that is essentially just a pile of volumetrics and lighting.
Whenever I set my project to GPU Compute mode (and set the tile settings to optimal for that), I run the risk of crashing my computer the moment I hit Render. I've Googled around for this issue, only retrieving responses for "Display Driver has stopped responding" messages and black image outputs during rendering. In my case, my displays just turn off after displaying "No Signal". It does not happen EVERY time, though, and I'm having trouble pinning down the trigger.
I've given it 5 minutes of black screen in hopes that it would come back after the scene finishes rendering (in the attached, the current settings usually wrap up after about 2 minutes on my GPU). I have also checked every optimization setting I could find in the project in hopes of alleviating this to no avail.
This has not happened yet in a simple scene. I am exceedingly new to Blender so I can only assume that I've done something terrible to my setup here. However, I would also not be averse to any sort of GPU version of Memtest that I have not tried, in case it's something hardware-related.
CPU Compute mode is not really an option for me, my aging i7 takes almost 30 hours to complete rendering at 1920x1080 (16x16 tiles, path tracing, 7 threads so I can still use the computer, 576 samples after hitting "Square Samples").
Specs:
 - Blender Version: 2.77a
 - OS: Windows 7 Ultimate x64
 - CPU: Intel i7-2600 @ 3.4Ghz
 - GPU: NVidia GeForce GTX 780 (3GB)
 - RAM: 16GB DDR3 1600
Project Files: https://dl.dropboxusercontent.com/u/39096583/Blender.zip
P.S. Thank goodness for RAID1: every time this issue happens, I get notified that the array needs to be verified and repaired. Feeling good about my choice to go with that over RAID0 or a JBOD...

Since smaller scenes work, could your GPU have not enough memory for that complicated scene? I have no GPU but I know all scene has to be stored in faster, but smaller GPU memory, or it cannot be rendered there... You could try somewhat splitting the work in smaller parts and rendering them separately, then compositing them back later.

I thought about that, but the scene data never indicates that it's exceeding 50 MB of RAM usage. Is there a way to directly check how much the raw scene data really takes up, if the "Mem" space is inaccurate? Also, I'm not sure splitting up the image would work all that well. Eventually this is supposed to be made into a skybox object (reflective cube, baked textures) so the compositor won't be of use to me (unless I'm missing something on that), and I'm trying to get cloud self-shadowing to play a part in the scene dynamics, so I'm not sure how to split without breaking shadows.

Update: Ran GPU-Z while rendering (this time successfully, still can't find the trigger) and the scene data pushes the GPU memory load up by almost exactly 1 GB. I'll continue to run tests to see if I can get this to black-screen and what the memory load gets to at that point...

I think the dual 780s might be the cinch here, that or Win10 handling errors better than whatever the heck my computer is doing.

Are you using Branched Path Tracing on GPU?

Cetagon: beginning to think it has something to do with my local config. Anything you want me to look at in particular?

Matt: I've had the issue with both settings, but currently I'm using flat Path Tracing.

At this point I'm fearing some sort of hardware damage. No joy after full reinstall of Blender and "Clean Install" of latest NVidia drivers. I had GPU-Z set to log to file during one of these tests and it only showed VRAM going to a maximum of 1.8 GB. In fact, everything on the log appeared to be nominal. I'm really not sure what to make of any of this.

I have the same problem. Windows 10 Pro workstation crashes with the most simple scene during Cycles Render. I have two GTX 970 boards.  I have updated the drivers to the latest version.  I have found that the crashes occur regardless of setting the GPU usage to None, One GTX board or both GTX boards - no difference.  All settings produce a crash on Cycles Render.

I have 3 GTX 770 and avoided updating from win 8.1 to 10. It was a constant battle to keep the Nvidia driver preserved and not get updated. I was forced into updating to win 10 and all has been smooth. Now I have the latest Drivers and 2.92.0 runs great.

It's common for this problem to be caused by running out of VRAM on your card.
One way to alleviate the problem is to reduce the tile size. Some of the things in a Blender scene can be swapped to and from the GPU on a per-tile basis. In those cases, a smaller tile size means less data on the GPU.
Other things will be the same size on the GPU regardless of which tile is being rendered, or how big the tile is. Hopefully, that overhead is small enough that reducing the tile size will help.
Cetagon's suggestions are also worth checking out.

I will definitely give your and Cetagon's advice a try. However, running GPU-Z as mentioned in the other post shows that VRAM usage is not changing between tile sizes, whatever that bit of information is worth. Whatever the case may be, it definitely seems to be instantiation based as it happens just after the data is sent to the GPU, never mid-render.

If Blender is requesting more VRAM than is available, that RAM will never be allocated. E.g. if Blender is using 50% of your VRAM, and then for another stage of the process Blender asks for a chunk that's 60% of total VRAM, then the driver will deny the request, Cycles will crash, the driver will crash, and you'll never see the VRAM increase. I agree with your suspicion that it's NOT vram related, but I'd keep that in the back of your mind, because it's not totally out of the question.

Yeah, but what's really strange is that the only info I can find on this is that Blender gives an "Out of Memory" error on the info bar, or Windows displays a "Display Driver was Unresponsive" message. Also my scene is (currently) a 2-pass render, one for the scene and one for the star alone for post processing needs. While watching GPU-Z during a successful preview-level render, the RAM usage did not change until the render completed.

During last two weeks I spent hours to solve crash problem with cycles rendering on my pc. Whatever I had been trying - nothing helped! I had usual 'cuSynchronize' and 'cuMemFree' or something like that which are well discussed on blender support forums but nothing helped. I played with nodes and even removed some shaders, I played with scene render triggers, with render setup and a lot of other things including Windows 7 regedit TrdDelay and Nvidia driver setup.
During two weeks each second render in 5-15 minutes I had crash and I wrote special script to continue baking from mesh where it had crashed on. So it was a disaster.
After all I decided to add radeon card to split display and rendering facilities. Just after that I got couple of hours of rendering before next crash. And that was a good achievement meaning all before. Then I paid an attention on GPU temperatures - I use multi GPUs so they obstruct each other from fresh air as stay close in pci-e ports and to install another card I used raiser and moved one card away opening fresh air for others. In addition I played with nvidia overclocking switches and reduced GPUs nominal working temperature.
I am not sure that was the real solution in my case whether display and render separation helps or temperature - I didn't want to repeat all of that but could say that just by adding separate card for display and reducing temperature of GPUs from 80-87 to 75-77 solved the case I had with Blender rendering on GPUs. Also I mentioned that TdrLimit doesn't work well and do not prevent driver reloading. Finally I put all DWORDS I have found on Microsoft site putting up to 1800 seconds to TdrLimit - I anyway had crashes. Finally I changed tiles size from 2048 to 1024 and then to 512 to ensure that any heavy samples will be rendered in 10-15 seconds. Hope it will also add stability.

My issue had nothing to do with heating, as the crash happens seconds after hitting "Render". Load temps on my card struggle to breach 65°C even on Furmark (I got it up to 71°C only after an hour of running).
Also, I still have yet to find a solution to this issue, in case anyone is wondering. I've just kinda given up on the project until I can get myself a shiny new NVidia 1080.


text:
How to bake all animation at once
I have a complex animation with a lot of objects using-Shape keys, Nla tracks, particle systems, physics, path following...
But to use a render farm you need to bake everything to key frames.
Is there a way to select all and bake? Or correct me if I'm wrong about something
Thank you

Are you sure they're asking you to bake all to keyframes and not just that any physics, like particles, need to be baked to a cache?

Try asking them directly what they mean.

Yeah, its true. You only need to bake physics to cache. :)

@Cimo Can you make your insight into an answer, please?


text:
Armature bone glitches after 180 rotation with copy rotation constraint
Setting a copy rotation constraints influence to a number like 0.200 starts snapping the bone weirdly after passing 180 degrees of rotation. How can I fix this so that it keeps adding rotation?

From the perspective of constraints, there isn't any such thing as rotation outside the -180, 180 range.  200 degrees of rotation is actually -160 degrees of rotation.  You can't do it with constraints.  Drivers may get you what you want (depending on what it is that you want.)

I see. How can I use these drivers then to copy rotation? For example, even copy rotation from two bones just at the influence of 0.2 to 0.8

Googling "Blender driver tutorial" would probably be a good start.  There's plenty of information out there on them.

Somewhat related https://blender.stackexchange.com/questions/164765/rotation-driver-skipping-backwards-after-90-degrees

Thank you very much I've managed to get some excellent results with these copy local rotation drives. All you have to choose is the amount of division on the variables to change its influences like so
https://i.imgur.com/8hPVjAf.mp4
https://i.imgur.com/OqL4cTk.mp4
https://i.imgur.com/T3CJHNI.jpg
https://i.imgur.com/HZUHB1x.jpg
https://i.imgur.com/1xBA4cA.jpg
Yet this begs the question, how would I copy global rotation like this? Or even apply the bones parents rotation to the equation. Like the copy rotation constraint with world space or local with parent

If you want to do drivers in a different space, you need to use them on something in that space: something unparented, in lieu of world space; the parent, in lieu of local-with-parent.  There is no way to convert local space rotations outside of -180,180 to other space rotations outside of this range (there's a certain ambiguity involved, and that's part of why constraints work the way they do.)  Imaginable problems are probably solvable, probably via duplicated bones and use of other constraints like copy location to emulate parenting, but we'd need details to help you solve those problems.


text:
I locked one axis in edit mode and don't know how to unlock
I just have a simple plane and I can't move it in z axis.
even if I rotate it, it just shrinks onto its self. Rotates normal in object mode
and the weird lock seams to follow the objects orientation from object mode
I must have hit some shortcut by accident but I can't figure it out.
plis help

Omg it was scaled to 0 on its flat surface... and I could not see it
My bad XD


text:
Trying to make an addon to streamline asset browser use
I would like to create add-on for blender 3.6 that allows me to mark an asset in the current file I am using then let me choose an unopened file I want it appended to. This add-on should give me options for selection for the file path of the unopened file I want to append items I've marked as an asset to.
In the same folder as the blend file I want to append these assets to, there is a file there called 'blender_assets.cats'. this file contains the names of the categories of assets for the chosen unopened file in that folder I want to append items I've marked as an asset to. This file contains the catalog names for which I want to create a dropdown menu showing the list of catalogs.
The names for the category occur after the second semicolon on eack of lines 9,10,11,12, and so on until the end of the document. I need to write proper code for handling this selection and saving the asset to the correct catalog name for the specified blend file should be written into this script.
If no 'blender_assets.cats' file exsist the catalog name should be "Catalog"
Finally I want the the add-on to have a backup file path selection button and function that allows me to save the blend file that retains its name adding 'backup" and a timestamp, to the path that's is specified. This function will back up the original before making any changes to to it. This function will also creates the new backup file before deleting the previous backup.
I've looked at the blender API and the add-on seems totally posible but I can't seem to get the code to work.
The output you produce should be a complete python script that makes a the described add-on interface in the navigation tab under the "create" tab. It will be named "Append to File"
This interface should have

A functional directory selection button allowing for the selection of the desired file to append to.
A funtional catalog selection button that gives a drop down list that is populated by the 'blender_assets.cats' file in the manner I described.
A funtional, optional that uses a check box to activate, backup directory selection box with a button to select the directory from that creates and names the backup in the described manner.

Here's the code I've come up with but cant seem to get it to work properly.
Could I get some advice on what I'm doing wrong?
bl_info = {
    "name": "Append to File",
    "blender": (3, 6, 0),
    "category": "Object",
}

import bpy
import os
import subprocess
from datetime import datetime

# Directory to save temporary files
TEMP_DIRECTORY = bpy.app.tempdir

class AppendToFileOperator(bpy.types.Operator):
    bl_idname = "object.append_to_file"
    bl_label = "Append to File"
    bl_options = {'REGISTER', 'UNDO'}

    filepath: bpy.props.StringProperty(subtype='FILE_PATH')
    backup_directory: bpy.props.StringProperty(subtype='DIR_PATH', default=bpy.app.tempdir)
    select_catalog: bpy.props.BoolProperty(name="Select Catalog", default=False)
    catalog: bpy.props.StringProperty(name="Catalog")

    def execute(self, context):
        # Make sure a file is selected
        if not self.filepath:
            self.report({'ERROR'}, "No file selected")
            return {'CANCELLED'}

        # Make sure the file is a .blend file
        if not self.filepath.endswith(".blend"):
            self.report({'ERROR'}, "Selected file is not a .blend file")
            return {'CANCELLED'}

        # Append to the file
        self.append_to_file(self.filepath)

        return {'FINISHED'}

    def append_to_file(self, filepath):
        # Save current file path
        current_filepath = bpy.data.filepath

        # Backup current file with timestamp
        timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
        backup_filename = bpy.path.basename(current_filepath) + timestamp
        backup_filepath = os.path.join(self.backup_directory, backup_filename)
        bpy.ops.wm.save_as_mainfile(filepath=backup_filepath, copy=True)

        # Save the current selected objects to a temporary .blend file
        temp_filepath = os.path.join(TEMP_DIRECTORY, "temp.blend")
        bpy.ops.wm.save_as_mainfile(filepath=temp_filepath, copy=True)

        # Script to run on the target .blend file
        catalog_string = f'"{self.catalog}"' if self.select_catalog else "None"
        script = f"""
import bpy

# Filepath of the temporary .blend file
source_blend_filepath = r"{temp_filepath}"

# Catalog to append the asset to
catalog = {catalog_string}

# Load objects from the temporary .blend file
with bpy.data.libraries.load(source_blend_filepath) as (data_from, data_to):
    data_to.objects = data_from.objects

# Link the objects to the current scene
for obj in data_to.objects:
    if obj is not None:
        bpy.context.collection.objects.link(obj)

# Save and close the .blend file
bpy.ops.wm.save_mainfile()

# Quit Blender
bpy.ops.wm.quit_blender()
"""

        # Path to the Python script
        script_filepath = os.path.join(TEMP_DIRECTORY, "append_script.py")

        # Save the Python script to a file
        with open(script_filepath, "w") as file:
            file.write(script)

        # Run a new instance of Blender with the Python script
        subprocess.run([bpy.app.binary_path, filepath, '-P', script_filepath])

class AppendToFilePanel(bpy.types.Panel):
    bl_label = "Append to File"
    bl_idname = "OBJECT_PT_append_to_file"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "Tool"

    def draw(self, context):
        layout = self.layout
        operator = layout.operator(AppendToFileOperator.bl_idname)
        layout.prop(operator, "filepath")
        layout.prop(operator, "backup_directory")
        layout.prop(operator, "select_catalog")
        if operator.select_catalog:
            layout.prop(operator, "catalog")

def register():
    bpy.utils.register_class(AppendToFileOperator)
    bpy.utils.register_class(AppendToFilePanel)

def unregister():
    bpy.utils.unregister_class(AppendToFileOperator)
    bpy.utils.unregister_class(AppendToFilePanel)

if __name__ == "__main__":
    register()
```

And what point it starts to work wrongly and what is the expected behavior?

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer.


text:
Point instance in 3.5
I'm following tutorials on the blender guru page so I can learn the program well.  Unfortunately, the tutorials are using an older blender program.
For instance, I'm following the tutorial on the gumdrop and it says that I need a points instance node in 3.5.  The only problem is, there isn't one.
Was it replaced with something else that I can use?  This is all the points options that Blender 3.5 has.

There isn't one called that in Blender 3 and above. Maybe Instance on Points under the Instances category?

That Blender Guru tutorial was done in Blender 2.92 in the early days of Geometry Nodes. There have been lots of changes since then so I'd look for a more up to date tutorial maybe using 3.5.


text:
Is there a way to merge multiple blend files?
I have around 100 separate .blend files that have one material each, is there a way to merge the materials from all of these blend files into one?
I am trying to do this to add the materials into the asset browser without having to merge them and add each material one by one, so I can easier manage my asset browser.

I'll assume that your files are placed in the same directory—or a couple of folders deep in the same directory. If so, in the file browser that pops up when you click File > Append, you can switch the Recursion level of your display to one of three levels to see all append-able data blocks present in the .blend files from that folder:

You probably don't want to see all data blocks, so you might wanna filter out the rest and only leave Shading on:

Now you should be able to select multiple materials from different files at once to append.

Thanks a lot, by any chance is it possible to mark all materials in a blend file as asset?

Not in front my computer atm so I can't check but if you switch the Outliner to the "Blender File" mode you should see a list of all data blocks in the file: https://docs.blender.org/manual/en/latest/_images/files_data-blocks_outliner-blender-file-view.png You might be able to select multiple materials at once and mark as asset there?

this worked....

EDIT: to read all materials, you don't want to use bpy.ops.wm.append but rather you want to use library management code.  Updated the answer to reflect this.
There is no automatic way to do this.  The manual way is to open a new blend file and append the materials from each of the 100 other files to that file and then save it.
You could write a Python script to do that.  If, for instance, all of the blend files were in the same directory, the script could iterate through each file, appending every material from that file using bpy.data.libraries.load  Here's an example of doing that modified from the matlib manager addon
with bpy.data.libraries.load(blend) as (data_from,data_to):
    data_to.materials = data_from.materials

Note that this is equivalent to linking the material, but now you have a list of names.  If you want to append instead, you would then go through the list and call bpy.ops.wm.append for each material.
Here is the starting point for code to accomplish this.  It's only a starting point because it doesn't handle the error cases, like not being able to open a given blend file and it doesn't do any filtering.
import bpy
from pathlib import Path

blendfilespath = Path(PATH_TO_MATERIALS_DIRECTORY)

for file in blendfilespath.glob("*.blend") :
    file_path = Path(file)
    inner_path = "Materials"
    with bpy.data.libraries.load(str(file_path)) as (data_from, data_to):
        data_to.materials = data_from.materials
    for linked_material in data_to.materials:
        object_name = linked_material.name
        bpy.ops.wm.append(
        filepath=str(file_path / inner_path / object_name),
        directory=str(file_path / inner_path),
        filename=object_name
    )

https://blender.stackexchange.com/questions/245555/batch-add-to-asset-browser any good?

@JohnEason That's good if you want to tag a lot of things in existing files as assets for the asset browser.  The problem here seems to be how to append a lot of content from many other files to one file.

Ah ok. I remember it being discussed at the time @Gorgious posted his code, but must admit I'd forgotten it didn't include appending them into one file.


text:
A very confusing cursor when sculpting

[![When sculpting the cursor has two circles and a cross hair. It is extremely distracting to say the least. I don't even know what the purpose of the double circles are. Is there way to disable this complicated icon or at the very least remove the cross hair?

When sculpting the send dot will show where it will be mirrored.

Thanks. What do the inner and outer circles indicate?

The center colored dot snaps to the nearest vertex and also appears on the other side of the model if you have mirroring turned on, as Yohello said. As far as I can tell, the outer circle shows the size of the brush, and the inner circle represents the strength / falloff of the brush, and increases in size as you increase the brush strength.
If you want to disable the cursor entirely, you can uncheck the "cursor" box on the right panel. If you do this, There will only be the normal mouse icon to show the cursor position until you click the mouse / press down the tablet pen to begin sculpting, at which point there will be no cursor.
Or, you could go to the cursor color settings and change the cursor alpha to 0, and a simple crosshair will be shown at all times instead of the dot and circles. Hope this helps!

1) you have enabled symmetry, the dot on left indicates where the symmetry of your brush will apply.
2) the inner circle indicates strength of the brush. You can change size of your brush by pressing F, when you pres SHIFT+F you can adjust your strength.


text:
Proportional editing problem
I'm new to blender and I have a problem that I can't solve and where the internet won't help me.
I have a column and want to make it look like it was cut. So I want that the upper vertice goes into the blue circle and that the other vertices makes a straight line to the lower vertice. I tried to use the proportional edit tool but none of the meshes  solves the problem. So is it possible to use the proportional editing but fixing a vertice and making the other vertices do a straight line between the fixe vertice and the edit one ?

Add a cube, and position it so that its lower face sits where you'd like the cylinder's vertices to be. The tip of the cylinder should be inside the cube.

Select the cylinder. In the Modifier Properties tab, on the right-hand side pannel, add a Boolean modifier. Make sure it's set to Difference and, under object, select the cube (be aware that there might be many cubes in your scene; make sure to select the right one).

Your cylinder should now bear a cut as the one you described. If evertyhing seems to be in order, hit Apply in the boolean modifier and get rid of the cube.

Thanks for your help. Your response was really helpfull.

The other answer is good, but another way while steering clear of modifiers would be knife tool. k to start, then c to lock it 45 degree angles, then z to cut through the whole mesh (you may wish to use hide h to hide parts not to be cut) then Enter to confirm the cut. Then just delete the top part and fill the resulting loop.

Thanks for the response. This worked perfectly well.


text:
Can’t fix jitter effect on a moving character with a smoke simulation [mantaflow, blender 2.82]
I have a moving character that is to be replaced with a “smokey” one. However, no matter what I do (I think I fiddled with almost every possible combination of parameters), I always run into a problem, be it either:

The simulation is too varied between frames and looks psychodelic.
Simulation has too much of a “ladder” effect (cranking up sampling substeps doesn’t help)
Simulation is jittery and “noisy”

After hours and hours of fiddling with parameters, this (link to youtube) is the best result that I managed to achieve. And it is absolutely terrible and unusable. (don’t look at the compositing, it is just a render of the simulation)
These are the settings used for this simulation (the scene is in 30FPS, no wind force is used, blender 2.82):

So, how do I fix it? Obvious and most crucial problems are:

It is jittery af.
Trail of smoke that character leaves after them is too disjointed (especially noticable in the first second of the video).

Thanks for help in advance.

Managed to fix the jitter, but not the "laddery" trail.
Changes:
Set Heat to 0.2;
Disabled noise;
Set dissolve to 12 frames.
Then in post fixed the disjointed trail via the vector blur effect.


text:
Grease pencil overlapping only in render view?
I have a small room I'm working on, and I adjusted things to how I wanted them in the Layout tab. I did want to give it a slight hand drawn feel, so I know this means the strokes aren't super accurate. But there's a weird overlap of lines in the final render that doesn't seem to go away even when I deactivate the line layers, so I'm not certain if this is a bug or if I'm just too much of a beginner to identify the issue.
I have a thread of images regarding the issue here, and how it looks when I tried different solutions:
https://i.sstatic.net/EvNcm.jpg
I have the object stroke depth order set to 3D location. I'd really appreciate any suggestions you guys can give!

Seems to be a similar issue as this question: https://blender.stackexchange.com/questions/177488/grease-pencil-strokes-showing-through-fills

Did you ever figure this out? I had a similar problem and also no answers from any pros. The nearest I could figure is that you could try putting each piece on it's own layer and then organizing the layers having the correct ones on top to cover overlapping lines.

Enable the Z pass
(Blender 3.0.0) Scene > View Layer > Passes > Data > Z


text:
Weird warping of render image in Camera track

Hi guys, Please help me fix the render image as there are weird warping in the corners of the image. I'm using cycles.

If you are un-distorting the image that is natural.  Read: https://blender.stackexchange.com/questions/113907/motion-tracking-the-edges-of-undistorted-footage-are-cropped-and-so-are-the-el and https://blender.stackexchange.com/questions/38478/why-is-my-footage-smearing-out-towards-the-border-on-rendering-an-image/38489#38489 and https://blender.stackexchange.com/questions/15620/how-to-determine-lens-undistortion-values-for-motion-tracking/15622#15622

Hi, This issue here is only caused by wither the render itself or by the camera track.

I dont think it's a nodal thing.

yeah it's my bad i haven't mentioned im actually relatively new to blender.

I actually am not sure on what examples you're specifying. Could you please let me know but i can say that the refine in the solve that is Focal length, K1, K2.

I hope this helps at all


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Complex grid patters for chair
I need some help in creating a complex(might not be complex) grid pattern for the back support of a chair.
I attached the image it is based on.
Please note that I have also created the outer frame, do let me know if that's necessary or if I'm headed in the right direction.

Here is a simple and basic way I would go about it.
Made you this short video.
-Subdivide a Plane, Shape with "Proportional editing", Add wireframe mod and Subdivision surface -
enter link description here


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Randomizing Object without changing every second. Geometry nodes
hope you're doing well!
I am currently facing a couple setbacks with using geometry nodes for the first time. I've used 2 tutorials in tandem to make the attached node setup.
The gist of it is, I need hexagon shapes with a specific material to scale from 0 to a certain number as the camera goes forward. This scene has been tracked in after effects and bought in blender. It does look good so far but the two issues are-

The object(hexagon) keeps changing to another one as soon as a new one pops in.
I need to tweak the geometry proximity node so that I can alter the distance once it passes through a tighter space.

Sorry if I am unable to explain that very well, I have attached a couple things to possibly further the explanation.

Your question needs a lot of detail.... How is a "mesh line" becoming an hexagonal shaped distribution? How are you assigning material? How is the material texture selected? So many things not shown that it's quite impossible to guess.

I suppose you have an object info node in the shader, taking a random from it. I guess you should assign this random to "instances" in the geometry nodes with "store named attribute" instead. And take this value in the shader from an attribute node.

Hi @DanielMöller, I apologize yes. The hexagons are modelled separately, there are 15 of them, each of which has a unique material. I added the collection that housed all 15 hexagons into the geometry node. So the object wasn't modelled within the geometry node stack. I first took all 15 hexagons and then using geometry node, I instanced it in a very large area so there were 100s of them. I then use the geometry proximity node inside the geometry node stack.

And I do apologize, I didn't quite get the second comment you mentioned.
If I need to give any more details, please let me know. Appreciate the help.

Maybe use the ID input instead of index ? I'm not sure but it may be temporarily consistent even if you add/remove geometry.

Hi, alright, I solved the first issue, it was as simple as just ticking the "Pick Instance" box in the Instance on Points nodes.
Now I just have to figure out the placement thing, it may be just as simple as scaling the proximity object.