text:
How do I save my undo history as well to my blender file?
I want to get my entire session's undo history back when I load a Blender file.
This would allow me to undo as far as would have been possible, had I not closed Blender.
Can any in-built feature or plugin support this?

I wanted to ask the same for Blender 2.8* and I found this.

Related info: Blender's unusual handling of undo steps Devtalk: Undo Performance Must Be Addressed. Blender basically reloads the entire scene when you Undo a step. The backup scenes are kept in RAM, never actually written to disk.

And an interesting thread on ux.stackexchange: Undo History - Why limit it?.

as you mentioned there is a limitation.
this test shows you how many steps you can undo. In my pc I can undo only 32 steps:
import bpy

for i in range(0,100):
    bpy.ops.mesh.primitive_cube_add(enter_editmode=False, align='WORLD', location=(i, 0, 0))
    bpy.ops.ed.undo_push(message="Add Cube")

for i in range(0,100):
    bpy.ops.ed.undo()

I decompiled undo script
void ED_undo_push(bContext *C, const char *str)
{
  CLOG_INFO(&LOG, 1, "name='%s'", str);
  WM_file_tag_modified();

  wmWindowManager *wm = CTX_wm_manager(C);
  int steps = U.undosteps;

  /* Ensure steps that have been initialized are always pushed,
   * even when undo steps are zero.
   *
   * Note that some modes (paint, sculpt) initialize an undo step before an action runs,
   * then accumulate changes there, or restore data from it in the case of 2D painting.
   *
   * For this reason we need to handle the undo step even when undo steps is set to zero.
   */
  if ((steps <= 0) && wm->undo_stack->step_init != NULL) {
    steps = 1;
  }
  if (steps <= 0) {
    return;
  }

  /* Only apply limit if this is the last undo step. */
  if (wm->undo_stack->step_active && (wm->undo_stack->step_active->next == NULL)) {
    BKE_undosys_stack_limit_steps_and_memory(wm->undo_stack, steps - 1, 0);
  }

  BKE_undosys_step_push(wm->undo_stack, C, str);

  if (U.undomemory != 0) {
    const size_t memory_limit = (size_t)U.undomemory * 1024 * 1024;
    BKE_undosys_stack_limit_steps_and_memory(wm->undo_stack, -1, memory_limit);
  }

  if (CLOG_CHECK(&LOG, 1)) {
    BKE_undosys_print(wm->undo_stack);
  }
}

you can see how limitation calculated:
const size_t memory_limit = (size_t)U.undomemory * 1024 * 1024;

as  @Jachym Michal said in comments increasing this limitation is not recommended
I suggest you use Git.you can easily undo (checkout) by git commands

Git is a distributed version control system for tracking changes in source code during software development.

but if you like the automatic way you can commit after each change:
import subprocess
from subprocess import Popen, PIPE, STDOUT

import re

# undo step
step = 0
# repository path
repoDir = 'C:/Users/Kamali/Desktop/Test'

def gitCommit(message):
    global step
    step += 1
    cmd = 'git add . && git commit -am '+message
    p = subprocess.Popen(cmd, cwd=repoDir)
    p.wait()

def undo():
  global step
  step -= 1
  checkoutTo(step)

# check out to specific step
def checkoutTo(Index):
    cmd = 'git checkout ' + getStepRevision()
    p = subprocess.Popen(cmd, cwd=repoDir)
    p.wait()

# get specific revision from git log history 546bece2c66acb454878500689e3017b92c43d28
def getStepRevision():
    cmd = 'powershell.exe git show HEAD~'+str(step)+' --pretty=oneline --no-patch'
    p = Popen(cmd, shell=True, stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True, cwd=repoDir)
    output = p.stdout.read()
    p.wait()

    revision = re.search('(.*?)\s',output.decode('utf-8')).group(1)
    print(revision)

Update
if you don't know git commands
you can use git extension
after you undo (check out) you have to close and reopen blender to refresh
but these lines of code help you to reload it easy
import bpy

bpy.ops.wm.open_mainfile(filepath=bpy.data.filepath)

Tutorial
run this code and see what happened!!!
import subprocess
from subprocess import Popen, PIPE, STDOUT

import bpy

repoDir = 'C:/Users/Kamali/Desktop/New folder'

for i in range(0,100):
    bpy.ops.mesh.primitive_cube_add(enter_editmode=False, align='WORLD', location=(i, 0, 0))
    bpy.ops.ed.undo_push(message="Add Cube")

def gitCommit(message):
    bpy.ops.wm.save_as_mainfile(filepath=bpy.data.filepath)
    add = 'git add .'
    p = subprocess.Popen(add, cwd=repoDir)
    p.wait()
    commit = 'git commit -m ' + message
    p = subprocess.Popen(commit, cwd=repoDir)
    p.wait()

I could commit 100 steps with code


text:
Cycles. Why is the background on my layer not transparent?
I am new to blender and cannot get the compositor to work. I have a model plane and a background video:

In videos I have seen it work but it doesnt work for me.
Any help is greatly appreciated, thanks.

Do you mean from the drop down menu at the top? I am using Cycles Render

Where can I find this?

I am trying to get the plane model to show in front of the video and it still doesnt work and im confused

Oh sorry I was being blind as usual and hadn't put the plane in the frame. Thanks for the help, your solution fixed it.

source: Stack Exchange

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

sort: votes


text:
How to correctly export a rigged suspension object for use in a game engine?
I have made a simple car suspension in Blender, intended for use in Unreal Engine 5. I have built it as multiple meshes – one for each wishbone, wheel hub, damper etc., and created separate armatures for the front and rear suspensions. In order to use it in UE, I need to reduce the model to a single object with a single armature – and here comes the issue. Joining the meshes removes all bone parenting from them, as intended by Blender. Is there any way to Export the objects correctly without having to join the meshes and redo the entire armature?
For legal reasons I want to avoid posting the original file, but I might do it if strictly necessary.

Give to every bone an unique name (even if they are in different armatures), then choose one pair of rig and mesh as "Master":
Select every mesh except the Master, shift select the Master last (so it's "active", orangy outlined), Ctrl J to join them.
Do the same with the armatures (Master armature last and active).
Rename the joined armature as "Root", and you should be good to go.

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


text:
Why there are little spots during retopology and use subdivison face
Why there are little spots during retopology and use subdivison face modifier?

Th bottom picture makes me think that there may be some duplicate verts/edges/etc... that are interfering. Try merging by distance (Select all > M > By distance). If that doesn't do it, it just may be a matter of the Tri's. Blender likes quads and quads-only, especially on smooth shaded, rounded surfaces, and also especially with Subdivision Modifiers. You may have to find a way to convert it to quads.

it looks like you have edges on the mirror side? maybe first delete them?

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


text:
How to change level of detail of an image texture like in C4D?
In this C4D tutorial, the artist changes the level of detail of the texture to 4k. Is there a way to do this in Blender?

Texture in blender is set to "no limit" by default, so you have the highest quality and all depends on your image size. If you wanna change that down to something smaller, you need to go to the Render settings > Simplify > Viewport > Texture limit.

That option in c4d is for the viewport to display a better quality texture

Thank you for sharing that: I was not aware of texture limit. Is there a way to increase the resolution of a single image texture in node editor?

Your texture resolution depends on your texture original size. You could try to make it smaller like THIS

I tried that but they still appear low quality. Maybe im missing a step? I'm pretty new. Could you possibly try following link and see if you can mimic it in blender?

You should open a new question to describe the issue that you are having with the texture been render in low resolution, make sure to add your image of the viewport render and also your render settings. What the tutorial is showing is just changing C4D viewport level of detail from low to high not changing the texture size. also, make sure to use Cycles Render


text:
How to make grills in blender?
I'm following this tutorial on how to put grills on teeth but the artists uses C4D. There is a point where he changed the level of detail to increase the resolution of the image texture to make it the grills look better. How would I go about this in blender?

Unless you're using some kind of machine learning algorithm which I doubt is integrated in Blender, you can't upscale an image texture like that. You can downscale if you have say a 8k resolution to 4k, but not the other way around. Lost data remains lost. Also please don't post the same question twice. If your question hasn't been answered you can try and improve it instead of posting a new one. Thanks :)

Your nodes set up are not connected in the correct way, if you are new to Blender, i highly recommend you to start with the basics in blender. Here is an image of a basic way to connect nodes.

And you also need some lights.

I have no idea what the image textures contain shown in the material setup in the question - so why do you say they are not connected in the correct way? The only wrong thing I can see is that the image texture for displacement is plugged into the normal input of the Displacement node, but it should go into height... and the displacement texture is not set to non-color (which I would recommend, too, but it's not obligatory). Anything else is okay as it is.

Of course you can add Texture Coordinate and Mapping nodes, but they are not obligatory either. Especially when using the UV output and no changes in the Mapping, that's what the other texture nodes use as default setting when there's nothing plugged into the Vector input.


text:
Video Editing rendering issue
I am trying to make a video, I watched several videos to get my settings correct and have made all of my cuts. In the preview, the video is exactly as I want, when I then go to render it, it renders something else, mainly all of the deleted scenes. The render window settings show the same as my preview and sequencer settings so I'm not sure where I'm going wrong.

Hello, can you post a screenshot of your compositing node tree ?

Hello and welcome. Please use a title that reflects the content of the question. It should be succinct, unique and identifying, and summarize what the issue is so that users can at a glance broadly understand what your post is about before opening it. Use the [edit] link below your post and avoid any emojis salutations or extraneous text not essential to the question. Remember, your title is the first thing potential visitors will see, and will weight heavily on their decision to open your question, which will directly affect the number of answers you might get.


text:
Animating wires attached to a head
Alright, so I'm decently new to blender (only about 130~ hours in engine) and I'm trying to... animate? Some wires, specifically.

I'm trying to have one end of the wires stick to the head while it looks around, and the other ends stay put. At first, I just had the first bone in the wire hooked up to the Head bone, which of course causes the entire wire to move when the head moves.
Now I have the end I want to stay still parented to no bone, which.. kinda works, but the wire model stretches quite a bit.

Looking left, the stretching is hardly noticeable, which is perfect for me. However...

When looking to the right, it stretches like this. Would there be a way to keep the shape of the wire? IE; locking the tail in place and allowing the head to move around? Or is there a better way to do this altogether?
Also, something somewhat related, I want some of the loose wires shown below to wiggle when the head moves. Anyway to do that beyond downloading an addon? Or would that just make the entire experience easier?

https://blender.stackexchange.com/questions/121357/how-to-create-a-cable-wire-for-animation https://blender.stackexchange.com/questions/90694/shaping-bezier-objects-and-applying-physics-collisions

Did you try IK?

I recommend a soft body simulation with a curve. Might not be very stable, but could make things much simpler.

https://blender.stackexchange.com/questions/242347/bending-wires-like-using-move-with-auto-ik-in-response-to-another-bone-rotation/242351#242351


text:
How to make Blender keyboard shortcuts work in a non-Latin keyboard layout?
my keyboard has two layouts - Latin (English) and Cyrillic (Russian). Currently, in Blender 2.8, keyboard shortcuts work only with English layout - at least, on a Mac and Linux. Is there any way to make them work with Cyrillic layout too?
(Because that constant layout switching is very inconvenient and slows the work down.)
Thanks!

I don't think you can, I cannot try it out but if you go into preferences and then to the tab with the shortcuts you could try to set your own shortcuts

Tried that on Mac and Linux. When I try to assign any Cyrillic character for any shortcut, Blender displays the Latin character, assigned to this particular key. Apparently, Blender accepts only Latin characters as custom shortcuts.

We made an add-on for Mac, which detects that language is not Latin, informs user with splash indication and switches automatically to Latin keyboard layout https://sergeytyapkin.gumroad.com/l/MacLanguageSwitch

If I can accidentally get it to work on my French keyboard (most confusing, btw), then you can get it to work for your computer.  Just get the keyboard, and set the keyboard (usually under language preferences, bottom right for windows, idk for a mac) up for the language that you want, and the computer will use that keyboard for everything, you don't need to do anything in blender.  That should do it.  Also, idk if this is just a Windows thing, but if you press alt-shift, it switches languages, which is annoying if you accidentally press it, then all of your shortcuts are messed up.

Thanks, guys. I have once again re-checked how blender operates on dual-layout machines. My findings so far:

on Windows 10 and  Linux (elementary OS 5, Ubuntu-based) shortcuts in blender work perfectly on both layouts (EN/RU) ;
on macOS Mojave - only EN shortcuts work. When I switch to Russian layout, blender doesn't respond to shortcuts.
So I guess, this issue is rather platform-specific, than blender-specific. If you know how to fix it on a Mac, let me know.


text:
Shrinkwrap tetris shapes without scaling or diagonal shapes
Hello guys I want to achieve a Shrinkwrap modifier from a sphere to a tetris shape like this. This shape was achieved by merging two cubes Scale (1,2,1) and (1,1,1) I also tried getting this shape by modifying the vertices but the results of the shrinkwrap were the same

I kind of already did other shrinkwrap shapes that worked perfectly like these

These are exactly the way I want the shrinkwraps to work by adding a shrinkwrap modifier and putting the mode to nearest vertex and setting the target as the shape I wanted but all of these were made with cubes in where only the scale got changed. The mode nearest surface point needed me to scale the sphere so it fits the shape but I cant scale the sphere (the game I develop doesnt allow it) so the mode nearest vertex did the thing I exactly wanted. This is what I got when I try to shrinkwrap the tetris shape

the shape doesnt select all the vertices as a whole shape like the ones before so the outcome will not be good. Somehow there are even triangle shapes outside the actual shape.
So how do I achieve the shrinkwrap to perfectly wrap around my tetris shape (just realized its not even a tetris shape) without triangles and that.
I'd be grateful for any tips (I am a newbie in blender btw)

Avoid Boolean whenever possible. For such simple shapes you should not need any "merging" , proper topology is important especially if you are deforming shapes where constant mesh density is helpful.
If you just want the morph into a sphere use the Cast modifier instead, it yields cleaner results.
Model the shape by extruding two faces of a default cube, then add a Subsurf modifier set to Simple to give it geometry to work with, followed by the Cast modifier set to Sphere. Control progression from the Factor slider.

I want to morph from sphere to the tetris shape and also without having a massive big ball

You can adjust radius and morphing order from the modifier


text:
How to make balls fall in Blender without passing through each other?
I am trying to make an animation to look like this.  Do you have any suggestions on how i can make many balls like this fall down on to each other?  I do not want them to pass through each other and want to stack each ball on itself.  I've attached an example of what I am trying to achieve.
https://www.storyblocks.com/video/stock/pile-of-gumballs-fill-screen-with-colorful-rolling-and-falling-balls-multicolored-spheres-in-pool-for-children-fun-abstract-transition-bright-3d-animation-for-composite-overlay-with-alpha-channel-skp37c9urk1ifyxc6
Thank you

Yes, as Sanbaldo says. If you're still having problems, you might need to increase the "steps per second" in the scene properties tab > Rigid body world.

You should set the balls as "Rigid Body - Active". The box should be "Rigid Body - Passive" (remove unwanted faces and recalculate normal internally, hide from render).
Animate and it should simply work.
check this file:
https://pasteall.org/blend/2097ed28b4cc4f77a15206e01ede3cf7


text:
Importing numerical data into Blender's fluids simulation
I am an engineer that typically deals with explosive, fire, and compressible flow (supersonic) simulations. I have my own code that can calculate a realistic 3D fluid simulation for some of these extreme environments, but I want to see what I can do for fun in Blender to make these simulations look "nicer".
I found this question from a while ago that is almost exactly what I am trying to do:
https://www.blender.org/forum/viewtopic.php?t=18319
However, this was written a long time ago and a few of the links are no longer available. Any help would be great!


text:
How do you make a fluid emit smoke and fire?
I am trying to make a liquid catch fire. However, I do not know how to make the fluid emit in the gas domain. A similar question was posted here:
How to light liquid on fire?
However, in the answer, it is mentioned that you need to make the liquid a mesh emitter. I can make the liquid a mesh, but I can't figure out how to make it emit in the gas domain. Any help would be great!

Since a mesh can only have a single fluid sim applied to it, it is not possible to have both a fluid and a gas simulation at the same time. Instead, you need to add an additional mesh that can follow the fluid simulation to host the gas (smoke and fire) simulation.
Start by setting up and simulating your fluid. Once this is complete, create a new mesh (eg, a sub-divided plane) and use the Shrinkwrap modifier to map this over the fluid. Add the smoke and/or fire simulation to the 'shrunkwrapped' mesh in place of the fluid mesh.
This can produce results similar to the following :

For simplicity I only rendered smoke but the same principle applies to smoke and fire. Also, you could add a particle system to emit particles of smoke/fire from the surface or change the smoke emission with a texture for added variability.

With the introduction of geometry nodes, this problem is easily solved by applying geo nodes to another object with the object node of the fluid simulation like this:
You can then apply the smoke simulation on it.


text:
Shader Node: How to loop a value input
I have created a graphic item in Shader using nodes, I would like to automate this graphic by looping a section, I have tried using keyframes to link a Value_Input_Node to a music track, but it will not let me bake it to the f-curves.  It marks the value in the Value_Node like it recognises it as a valid entity, but that is all!
I am a noob at Blender, so if I am missing something really obvious forgive me.
I notice there are no loop_nodes, no recursive_nodes etc and I have tried creating a loop by feeding a result back into the first node in a Math Add loop to increment the value, no luck there either.
Any help on this would be greatly appreciated.
I have seen on Github there are addons that include a loop function for a loop node, but it looks so convoluted I would need to gain more experience before I could even consider attempting this as I do not even understand some of the terminology, lol!

You can input #frame into the value node, making the value equal to the frame number at any given moment. You could use a math node to play with this value and try to get the result you want based on the frame number.

OK thank you for your promt answer, I will be giving that a try.  It sounds like the sort of thing needed to increment the value.

@ChristopherBennett Just to give you and others some feedback, #Frame caused a warning box to open to ask my permission to run the script, I gave it that permission, and it enabled me to link the Keyframe (using #Frame as the input in the Value Node) to the music, but I had to set the tick box (on the Burn Sound to F-Curves file view window) to 'Add'  this worked very well for my incremental graphics.  Thank you :)

Hey, glad it worked!

Just a question, what exactly did you put in the Value field, was it #frame, or #Frame. For me #Frame (as well as any other non int/float input) gives a warning, but #frame does not.


text:
Noise reduction from audio
I want to remove noise from audio in blender vse. I am new to blender and I want to use it for video editing.
Can anyone please suggest some way to reduce noise from sound in vse

Blender's Video Sequence Editor is very simple for audio. i will Recommend you Audacity for that, it's free and Open Source

Blender is a poor choice for editing video, but is even a worse choice for editing audio. Use a dedicated audio editing app.

Can you seggest me some video editor

Resolve, openshot, shotcut, HitFilm Express, avid media composer first, premiere, vegas, final cut pro. As for audio use audacity.

If you really want to edit audio professionally at a good price, I recommend the products from https://acondigital.com/products/ ...these guys know how to write solid software. (No, I don't have anything to do with them, but I work with it myself) ...forget Audacity, that thing is a bug (but free).


text:
Why do objects keep passing through the cylinder?
I've written a code to drop trilobe shaped objects one at a time into a hollow cylinder in Blender, but instead of settling at the bottom, the objects keep passing through to the outside of the cylinder and falling off. How do I prevent this?
Note: I had created the trilobe by adding vertices around the three circular arcs of the trilobe, connecting them with edges, adding a face and then extruding.
Attached is the .blend file as well as some images to better explain my problem.

Firstly, check that you have Applied Scale to each of the objects and that your Normals are pointing in the right direction. Make sure the container has ‘thickness’ (could add a Solidify modifier) and set the collision shape to ‘Mesh’.

Okay, thank you. I had already made sure the normals were pointed outwards and set the collision shape to mesh. Can you please explain what you mean by applying scale to the objects? And also why is there a need to add thickness to the container. I did the same analysis for cylinders being dropped and it was working perfectly fine.

The simulation uses the ‘unscaled’ form of a mesh so if you have scaled a mesh (using ‘S’, for example) it may not behave as expected. Select the object and press Ctrl+A for the Apply menu and select Scale. This will ensure the simulation uses the object at its current size. For the Solidify, yes, your outward pointing normals will make the *outside’ surfaces respond to collisions properly, but from inside the normals will still be in the wrong direction if you only have a face as the surface - Solidify will help with that by adding geometry for inside and outside.

Hey, thanks for the response. I had put the dimension for all objects according to the default scaling (of 1) and had not scaled the objects later. Also, I rerun the simulation after pointing the normals towards the inside following your suggestion, but the issue still persists :( Would you suggest I rerun the simulations again following the steps for Scale anyways?

If you have changed the dimensions then this will have affected Scale and you will need to Apply Scale before rerunning the simulation. If you select an object and press ‘N’ to show the properties panel and the Scale isn’t 1.0 for each of the X,Y,Z directions then you’ll likely get an unrealistic simulation.

Hey man, it still doesn't work after all the changes. However, I noticed that changing the Cap Fill Type from Triangle Fan to Ngon prevent particles falling out the bottom of the container. Any help would be very much appreciated :(


text:
Advice on connecting meshes

Hello all
Is anyone able to advise me on how could I fill in the gap between the outside edges of the two Circles and connect them to the rest of the model

There is no simple method, you will need to completely rethink and redo whole model.

No chance of Extruding an edge and loop cutting or anything like that? I don't think I'd have to redo the whole model.

Found a way to do it, scale out the top of the circle select the vertices from 10 to 2 o'clock then S Y 0 then extrude the straight edge to the adjacent edge of the mesh.
Repeat for the Vertices from 8 to 4 O'clock locations.
Add Loop cuts and joining up the vertices using the magnet tool, select all and press W and click on remove doubles.

This way you'll not have quad topology and smooth shading and/or adding modifiers will be problematic. Also, could you add some screenshots to your answer?

@LukeD Aye 2 minutes bud, I'll take a couple screen shots, and the Mesh did need a little clean up nothing too major though.

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


text:
Rename bones name
I want to export a scene to collada to load it in Android openGl ES2, if I have many meshes each one has its own armature I noticed the root bone of all armatures by default called Bone, in collada I have to get skeleton from its name so if I let names as they are there is a conflict in names occurred, my question is am I have to rename bones before exporting to solve this or there is another solution?

This can be done via a script.  Do you also have a vertex group named "Bone" on each mesh assigned to each armature?

Yes I have  vertex groups for each bone called with its name


text:
I love the Pose Library - but once you apply pose at keyframe how do you see the pose name in action or dope sheet?
I have got my head around Pose Library. You have to be very careful to ensure the pose's you store are only associated with the bones you want to change. But once working pretty awesome!
Thing is once you keyframe a pose and switch to Dope Sheet or Action Editor it reverts to just showing you the transforms on each bone. I am guessing this is because the pose library is a bit of a hack which just transforms armature at keyframe then forgets about it.
Now perfect scenario for me would be to have a dope sheet view with keyframe timeline for armature  tagged with the pose lib/pose name. Any addons that can do that or a hidden feature of Blender I have not found? If not any way to tag or comment parts of animation in dope sheet to remember what the hell doing?
Thanks

I'm not sure it will help but you can create markers in the Dope Sheet: M to create, G to move, ctrl M to name, X to delete. You can create shortcuts to jump to next or previous marker. But if you move a series of keyframes the markers won't follow.

Thanks moonboots that is very useful. Good to know they don't move with key frames but I can work with this.


text:
Blender snap option through icon

This is the Snap rotation option in 3ds max, can any one help me out on this option in blender, I dont know whether this option is there or not in blender, the good part in this option is if i set the rotation degree to 90, when i rotate the object through rotation tool it will rotate in to 90 degree.

You can use this buttons, which are for snapping generally:

If you want to have a snap during rotation, press ctrl while rotating (this also applies for scaling and moving.
Or you could just type r z 180 on your keyboard. This would rotate your selection on the z axis on 180°.
Edit:
If you enable snapping and activate the right button (on the first picture) everything will snap to grid. You then can press N to open the right side panel and there you will find some settings for the grid.


text:
What causes rotating objects to 'slip'?
This sounds like it should be simple but I've googled and looked through SE questions but can't find a good solution to the following problem. I have a shaft with a keyseat machined into it, a key and a geometrically correct involute gear. I want this as true to life as I can, I want the shaft to rotate the key which then transmits its power to the gear using physics. After about four rotations, it looks as though the gear has rotated a little more than the shaft. If anything I would have expected the opposite. This is what I have:
1) a cylindrical shaft with a square keyseat (using a rectangular prism/boolen subtraction)
2) a key in the keyseat (just a rectangular prism parented to the shaft)
3) a complex geometrically correct involute gear (constructed using an XYZ surface to calculate the gear faces consisting of about 3000 vertices - the least number I could make it).
4) the gear and the shaft have rigid body collision settings set to shape:mesh, source:base, friction:1.000, margin: 0.040. It has rigid body dynamics set to damping translation: 1.000, damping rotation:0.000
5) the shaft has the same settings except for surface response(friction):1.000
I have tried changing the rotation and damping and found that if I turn on collision margin it makes things a lot worse. Could anyone help point me in the right direction please?

My guess is the general problem here is the physics system hasn't really been made for this sort of precision and this kind of mechanical simulation, or geometric interaction. It most likely lacks the mathematical precision and computational accuracy for this to work reliably. It is not really my area of expertise, but this would probably be best approached with constraints and/or drivers to animate it properly.

is there any reason you need to use a rigid body sim for this?

I don't know any better yet. My main motivation was simply to see what would happen. I'm a beginner at blender but have a technical/mechanical background. I want to do 'real world' simulations. I'm retired now and Blender is really good and is free. Other packages would be a big hit on my budget.

Well you may want to look into constrains and drivers then, it might be a lot more suited for this sort of mechanical animation and may yield a lot more accurate 'real world' results with less computer strain

The Rigid Body World default values are OK for crude approximations of physics without much computational overhead but can be tweaked to produce more accuracy. In particular, try adjusting the following settings :

Increasing Steps Per Second should give a better simulation as each simulated step will be smaller and so more accurate. Similarly, increasing the number of Iterations gives it more chance to settle on a stable solution. Enabling Split Impulse should stop objects bouncing apart at unexpected velocities if/when the simulation results in them overlapping.
Try significantly increasing the number of Steps and Iterations and see if that improves your simulation and also try with Split Impulse enabled and disabled. Once you've got acceptable results you can try gradually reducing them to get a good balance between realism and efficiency.

Thanks Rich. I tried just enabling Split Impulse however it slipped further and more quickly, seemingly at a faster rate. With Split Impulse disabled I then tried increasing the steps per second from 60 to 100 and then to 150. At first I thought it had worked but discovered that the slipping still occurred but after many more rotations. I increased the solver iterations and the bodies went flying away, with Split Impulse enabled or not. I'll keep trying different combinations.

I've found that simply increasing the Steps per Second to 200, leaving solver iterations at 10 and leaving Split Impulse disabled gives me about 1600 frames @ 24 fps of rotation without the gear slipping - so about a minute of simulation. Good enough for now - so thanks for the advice. I'll eventually learn more and get it right.

Excellent - glad to hear it's working. The ideal Steps per Second will also depend on how fast it's turning and how closely meshed the cogs are. Always best to go higher if you can afford the extra processing time for the extra steps. Also, once you've got the animation how you want it you can always bake it so that it doesn't have to recalculate each time.


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Blender app.timer does not function concurrently with python-osc server thread
I want to run a python-osc server concurrently with an app.timer in a python script. The problem is that I can get the server and timer to run separately but not together. The dispatcher mappings are contained in an external config file and this seems to work fine. There appears to be something about a running server that upsets the timer. I wonder whether any kind soul can assist? Any suggestions would be most welcome. Thx in advance...  This is the test set-up:
def  DataPathsImport():
    print("Reading in config data...")
    with open("/Users/<path_to_config_file>/linker_config.yaml", 'r') as y:
        dlinks = (yaml.load(y, Loader=yaml.SafeLoader))

def print_hello():
    print("hello")
    return 1.0

class OSC_Server(bpy.types.Operator):
    """Set up server"""
    bl_idname = "wm.osc_server_operator"
    bl_label = "OSCMainThread"

    count= 0

    def execute(self, context):
        global _report

        try:
            self.dispatcher = dispatcher.Dispatcher()
            links = DataPathsImport()
            for link in links:
                dataTuple = (link.get('tag'), link.get('dpath'), link.get('dtype'), \
                    link.get('action'))
                self.dispatcher.map(link.get('addr'), osc_callback_router, dataTuple)
        except: # be specific with error type
            print(f"There has been an error when assigning address: {link.get('addr')}")
        try:
            print(f"Creating server on port: {port}, at ip address: {ip}")
            self.server = BlockingOSCUDPServer((ip, port), self.dispatcher)
            self.server_thread = threading.Thread(target=self.server.serve_forever())
            self.server_thread.start()
            bpy.app.timers.register(print_hello)

        except OSError as err:
            _report[1] = err
            return {'CANCELLED'}

    def cancel(self, context):
        print("OSC server.shutdown()")
        self.server.shutdown()
        return {'CANCELLED'}

classes = {
    OSC_Server
}

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)

def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes): # unregister classes in the reverse order that they were registered
        unregister_class(cls)

if __name__ == "__main__":
    register()
    bpy.ops.wm.osc_server_operator()

Have you checked if the "Gotchas" apply?

For others vaguely interested in this topic: remove the brackets from serve_forever() i.e. change to serve_forever. If you don't, the running server will block anything else from running concurrently :)


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Blender 2.8 UV unwrapped regular shelves shows triangluar faces instead of squares?

As you see in the picture, the faces of shelves are shown as triangle faces w/ 4 vertices.
What did I do wrong in modeling phase?
How can I avoid this mistake in the future?
Is there a way to fix it instead of manually moving the vertices?
Thank you.

i just did 'Smart UV Project' and it made everything fine ha. but any input will be appreciated.

Hard to tell at the current resolution, but you probably missed at least one UV seam.  Try to think about seam placement like making a paper cut out model. https://www.youtube.com/watch?v=Y7M-B6xnaEM


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Should I make this model seperate objects or 1 mesh
I'm modelling a humanoid character made of both solid and flexible parts joined together.
To avoid problems when rigging should the objects be joined together then weight painted to get the desired result, or is there a better way?
I have joints like the one below all over my model, should the flexible part be connected to one, both, or neither of the solid parts?

join everything in the same object, it's the weight you'll give to each part that will make the mesh look flexible or solid, if a mesh is controlled by only one bone, it won't be stretched, therefore it will appear solid

Thanks for your help


text:
Morphing an object around another object
I'm trying to add an Aquila to the chest plate of a space marine I'm modelling. Is there a quick way to morph an object around another object as per the picture I attached?

@cegaton Thank you!


text:
Blender and Gimp linear workflow
a question for users who use Blender together with Gimp for Post-processing, Texturing, etc. etc.
How to work in Gimp 2.10.8 as if you were working in Nuke or Blender Compositor? I'll explain.
When I go into Nuke or Blender I have the possibility to linearize the input data (if these are sRGB), how can I do this in Gimp? Also in both Blender and Nuke I can turn on and off the sRGB LUT that is applied in display, is there something like that in Gimp?
Furthermore, Gimp now works at 32bit float, but are the calculations done linearly or are there limitations?
In output phase how can I then return to sRGB by applying the LUT in the data?
Thank you for your attention.

This sounds more like question about GIMP than Blender

You should just save renders as exr's, keep them linear through the entire workflow

GIMP is mangled up. Don’t expect it to do anything properly, and given it is display referred, it’s impossible to do scene referred work with efficiently.


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What brings 3d software to gain weight?
I would like to ask a somewhat unusual question. A few days ago I downloaded the 2.26 version of Blender and I noticed that it weighed less than 5mb, what I wonder is why today Blender (but in general all software like 3ds, maya) weigh 50 times more despite not having multiplied by 50 sometimes the same functionality (and this is especially true for Maya, which is enormously bigger than Blender, although I don't think it has a huge gap compared to the tools you can use). Why? I don't understand much about programming but I would like to know something more. Thank you.

There ARE huge gaps between those tools you can use, but a lot of tools might been used in very specified conditions. And for the programming aspect, when more function need to be integrate, the more conditions should be handle in some places. And so do the libraries needed to be included. Making the application package bigger, but better.

Check out Zipf's law (vsauce youtube video). So functionality is not linearly proportional to code complexity (software size).
Usually 80% functionality takes 20% time to code, but solving all the edge cases, weird interactions, bugs, etc. takes the 80% of time and code.
You can code a nice simple working example, but if you'd like to make it multithreaded, you'd need to link a huge library to the program and make your code more complex. And on a weak laptop you might not even see that big of a change in functionality.
If you'd like to make your program more robust, for example make sure bevel works correctly in all situations, or boolean, this can complicate the code several times more than was the complexity of the original one. It just does not work proportionally.


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How to edit the Quick Menu?
I would like to change the order of the shortcuts I have added to my Quick Menu. I cannot seem to find a way to do that.
Is it possible? And if so, how?


text:
Save optix denoised viewport render as is?
I am looking for a way to save the optix denoised viewport render as is (view - viewport render image). I was told there was a plugin for 2.79 but I cannot find it.
Would hope there's is a way to achieve that in 2.82.
Thank you!


text:
Switch between materials within material
So I'm wanting to create a laptop with a keyboard (obv) and I've got the brushed aluminium material I want to use as well as a texture with keys for the displacement of the physical keys and a mask to apply different materials to the plastic of the key rather than the aluminium of the rest of the body. So I want to apply a plastic material to keys according to white regions of an image and fall back to the aluminium for black parts. But as far as I know, there's no way to link materials into other materials. Essentially, the space between the keys should be aluminium.

The Aluminium texture is just a principled BSDF following a matte aluminium look. In theory for the black regions of the mask, I could simply use a copied version of the node, but if I do that, then any changes to the original material would be noticable.
Thanks

Group the contents of the material, that you want to have in multiple locations, then insert the group. Changes to the group will be updated everywhere.

@Leander You want to post this as an answer so I can accept it? Cause it worked. Thanks so much

Yes, that's perfect. Thanks.

To use nodetree elements multiple time and have all update, when you change a single instance, use node groups.

Grouping nodes can simplify a node tree by allowing instancing and hiding parts of the tree. Both material and composite nodes can be grouped.
Conceptually, grouping nodes allows you to specify a set of nodes that you can treat as though it were “just one node”. Node groups are similar to functions in programming, they can be reused in many places in a node tree and can be customized by changing the “parameters” of the node group.

To make a group, select the nodes and press CtrlG.


text:
Rigid Body Simualation not working properly
When I place a cube upon another object(the rigid body type of the cube is active and the other object is passive), and start the animation, pressing Alt+A, the cube gets displaced as opposed to resting on the other object. How to resolve this? I've attached images describing the problem.
The first image is the one before hitting the play button and the second one is after.

Try to Apply Scale first, then bump up the Iterations. How does your Convex Hull look like?

Where can I find the 'Iterations'? Where do I check and let you know how the Convex Hull looks like? I'm sorry, this is the first time I'm doing rigid body simulations.


text:
Solidify a complex hollow object in Blender

I am trying to solidify this object from the inside in Blender which was created using the Boolean modifier on a cylinder applied with five smaller radii and slightly longer cylinders. Using the solidify modifier doesn't work simply on this object as the holes begin to close after a certain thickness, nor does solidifying the cylinders before applying the Boolean modifier. I need to do this before I can duplicate particles having similar geometry and fill them into a container to simulate a packed bed packing.
As a second and maybe more important part to this question, does not solidifying this particle from the inside even matter from a physics/simulation perspective with regards to how the particles fall and interact with each other in the container?

A warning:  as far as I know, Blender doesn't directly support particle self-collision for particle systems, so you may need to employ a workaround.  If you search for "blender particle system self-collision", you'll find a number of things people have tried.

https://blender.stackexchange.com/questions/50252/can-i-fill-an-empty-object/

Solid is a relative term : ) especially in 3D computer graphics. Everything that looks solid in (almost) any 3D environment on a computer is made up out of points(or vertices) in space with lines(or edges) between them, with planes(or faces) filling up the space between the lines. But nothing visually fills up the space between these elements, and it is essentially a shell. Even though properties like volume and mass are used in physics simulation, this shell is (partly) used to derive values for such properties. So there is no need for "solidifying the inside".
The Solidify modifier is a modeling tool and can be used to create such a shell around a mesh that might otherwise not be considered solid, like a plane with no thickness. The Solidify modifier can give a plane the appearance of a box which has thickness, and if it has no holes anywhere in its shell, is considered solid.

Thank you very much. That helps a lot :)


text:
Matching walking from video to tracked scene?
I am doing a cgi background in blender to someone walking on a treadmill... I am trying to move the cgi background to match the guys walk. How would I go about this? I already tracked the scene but do I move the background or move the camera to match the walking? I am pretty new to blender and just need some advice :)

Please post an image of the shot. You don't really need to track the video. It could be a very easy thing to do, or a total nightmare. Please add detailed information on what kind of shot you are dealing with, and if describe the kind of motion within the shot.


text:
Dont know how to join shapes
I started with a single block with an image template and ended up at a point where two edges looped around and came into contact with each other. I do not know how to connect them so I ended up extruding a shape from where the arrow is in the image then aligning its edges with the shapes on either side of it, it looked fine so I went to do a subdivision surface and it ended up with this wonky shape sitting between the sides it is supposed to connect to as seen in the other image. Now i have no idea on how to fix this or if there is a way I am still a bit new to using blender and could really use the help.

Try going to edit mode, select all, then mesh > clean up > merge by distance. You may have to reduce the distance threshold in the box that pops up in the bottom left corner. Decrease the distance until it merges the two sides if necessary.

oh my god thank you


text:
Grease Pencil "nothing to erase" error
So I'd been using the grease pencil with no issues before, and now as I try to write/draw with it, I get the "nothing to erase" error as if I was trying to use the eraser tool. I'm not, it happens with the "Annotate" tool:
Something else that happens that is a bit hard to explain is: I'm using a laptop and a screen tablet. If I'm tabbed out of blender, looking at my laptop, and then draw using the grease pencil, it works, but as soon as I'm tabbed back into blender (from the first stroke with the pencil) it stops working and the Annotate tool acts like an eraser again. Is there any way to fix this?
(Not sure if it matters, but while trying to sculpt earlier, my tools would subtract while the + button was active, and add when the - was active. Idk if Blender is freaking out or if my tablet's pen has something going on?)
Anyways, thanks in advance!


text:
Resize Applied to UV Editor does not Save

Hello all. I am attempting to resize the skin textures on multiple models. In this instance, I have clicked on the skin mesh and opened the UV Editor. Navigating to Image Resize, I lowered the value to 1024x1024 and then saved the file. However, upon reloading the file, the mesh is back to it's original size.

When you say "saved the file" do you mean the blend file, or the image file.  Saving a blend file doesn't automatically save image files; you have to do that explicitly.

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

Thank you for your alacrity, Marty. My apologies for the lack of specificity. By "saved the file", I meant the blend file, not the image file. I had no idea this was a separate option. You have my heartfelt thanks.


text:
Strange volume that separates objects in selectable and non-selectable items
I am facing issues with non-selectable verteces, edges and faces in edit-mode. Some faces, edges and verteces of an object are selectable other are not. All belong to the same object, there definitively noduplicate verteces (I also tried to "merge by distance"). I'd like to understand, whether this behavior is a bug or a feature.
When I toggle to wireframe or solid mode there is long and stretched volume going diagonally through the scene. Everything outside this volume is invisible and not selectable in edit mode - everything inside the volume is visible and selectable in edit mode. Whe toggling to material preview or rendering mode, the whole scenery is visible. The "cutting" volume has the shape of a spotlight that seems to come from out of space, however I don't have any objects such as sun or spot lights, the might in any way (rotation, position, etc) correspond to this "spot-light" volume.
Is this a bug or feature?
Any idea, how to recover my project in the first case and what change in the latter case?

Thanks in advance
Boris

It looks like you have accidentally activated a clipping region or a render region. Try pressing Alt + B, or clear the regions from the View menu at the top:

Thanks! That fixed it! I mixed it with Ctrl-b. No idea, what Alt-b is good for. I'll find the answer for this question in the manuals, though.

@BorisGlawe If Christopher's answer helped solving your problem you should mark it as "Accepted", to signalize others there is a working solution for this problem. Please read here: What should I do when someone answers my question?


text:
Can't bake high poly normals to low poly
I'm trying to bake the hole and beveled edges of the high poly, but the bake results in either a blank map or a blank map with holes where the UV is. I've tried selecting the high poly first and then the low, setting color space to non-color, adding a cage, tweaking the ray distance and extrusion, matching the high and low poly UVs and shrinkwrapping the low poly. Both are exactly in the same place with rotation and scale applied.
high:
low:
normal map i get:

Hello, please share your object: https://pasteall.org/blend/

like this? https://pasteall.org/blend/432fc1f701294c3ab5222e931c668df8

Give visibility back to the high-poly object (I didn't know it was important for baking the normals). Also, increase a bit the Extrusion value in the Bake panel (something like 0.1).

This fixed it! Than you so much for the help!

Although the normals look a little flat, is there a trick to make them look deeper or is this just a limitation when working with normal maps?

This is a limitation, baking the normals will save the faces orientation, not the depth, it can fake 3D but it is not real 3D


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UV Unwraps incorrectly despite applying scale

I have been trying to unwrap this simple cylinder but it keeps unwrapping like this...
I have applied the scale and rotation, even location and it didn't work. I also tried erasing the applied memory and trying again but it still didn't work.
Conformal method doesn't work either.
I am completely stumped. No idea what's causing this :/ Any help is appreciated!

If you add another seem along the top circle and one of the vertical edges, it will give you a clean projection. Depending on your case, cube projection or smart project might work as well.

The generated layout is representative of the seams you marked on the mesh.
Since you only have one seam ring around the lower cap of the cylinder, Blender generates one UV islands from the lower cap and another from the rest of the mesh, which is the cylinders main part (or perimeter), and the upper cap - together in one island.
I normally prefer to mark both caps and then to add another seam on one of the vertical edges of the perimeter, so that the layout of the perimeter will be in the shape of a(n easily textured) rectangle, rather than a circle:

To reproduce this mark the seems as seen in the image (in Edit Mode --> Edge Selection Mode, select seam edges and mark seams via AltE --> Mark Seam.
Then select all edges (A), then UV unrwap via U --> Unrwap.


text:
Trying to bake a scene with multiple objects & unique UVs into one object with 1 UV
I'm having issues with trying to bake a scene I made.

I have many objects, a bunch of them with their own UV maps and textures, and I'd like to join them all together into one object with one UV map and one texture so that I can bake it as one. Things I've tried:
-Joining all objects together, then trying every type of UV unwrap--this ends up with all the UV maps overlaying each other and textures becoming misaligned and messed up.
-Duplicating all objects, joining the duplicates together, and trying to bake the textures of the originals into a new image on the duplicates. This ends up taking forever, with things ending up mostly black and still odd-looking.
-Baking everything separately then joining them... again, textures become messed up.
-Using the Texture Atlas addon, but that doesn't seem to work either following various guides I've found on YouTube and other forums.
I've watched a bunch of YouTube tutorials and have tried following along with answers I've found in this forum, but with no success. Could anyone offer me some advice?
Here's the file if you'd like to take a peek: https://drive.google.com/open?id=0B2qBRR30UYv5UW90cGpVbmktaGc
Thanks in advance for any help anyone could offer! I really am enjoying learning Blender, but this has been a big roadblock.

did you try to add an additional UV Map to bake with


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background clip not rendered in cycles anymore
Good day.
I think this is the right place for my problem, since I read something similar to this here. Maybe a bit more confusing.
After a bit more than eight hours of trying to figure out it by myself I'm really in desperation.
I tried to learn about camera tracking with the help of a YT tutorial from Blender Guru (https://www.youtube.com/watch?v=CVPcT0dJmoY). Everything went fine till this one point when I again tried to render the scene to check the results. The problem: my background clip disappeared. So far - nothing special. I was sure that I did something wrong and just tried to figure out what it was.
Thankfully I safed a working copy before I started to refine my "hole in the street". A copy, where I just put a cubic hole in the street instead of a more complex shape.
This copy is still working. But the more advanced version doesn't. I spent a whole day of searching and comparing the two versions. And I'm pretty sure I am overlooking something. But I still can not find the mistake I certainly made.
One weird thing I need to mention: after the rendering the background sometimes "blinks" and shows up for a millisecond. But thats all.
I attached the picture of the failed version, since I am not allowed to add two pics in my post. But there is a successfull rendered simple "cubic hole" version.
I checked all the nodes, the scene settings and what not. I really hope someone in this great community is able to help!

I suggest going over the tutorial again in very precise detail. I did the tutorial a few months back (i think still november) and it worked fine. You have probably caused the problem to occur somehow.

I did the whole thing again. I went through all the details, at least I tried my very best. But still no clue what caused this problem. It works in my newer version. But all setting are exactly the same.


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Particles hair rendering too dark
Why is the texture on the arm hair rendering so dark?

Are the hair particles around that area more dense than the rest?  That could cause the problem.

No not really, I apply the hair particles to the entire body. So why would it only be dense around the right arm?

Did you add hairs in particle edit mode to the spot?  or did you comb those hairs down and the rest are standing up?


text:
Hair Particle, final Render shows less particles than in the viewport
I'm using Blender 2.8 and having a problem. I'm following a towel tutorial and I've set the number of hair particles to 1000000 and i get a result like this:
Problem

The only way it will fill up the towel is if i set the view port display at 100%
Settings

Final

Every video I've seen on hair doesn't say this is necessary. Have i missed something here? is it a 2.8 bug? Thanks in advance!
Tony

So i figured it out!!! It happens when the hair dynamics button is checked. I have unchecked it and it works as it should

Is this a bug?

It is not necessary. You are probably thinking that the view port rendered view is the same as the render. This is not so, the view port render view is exactly what you see on the view port, but when you set the amount of particles to a smaller percentage, in the final render (press F12), there will be the correct amount.
(view port rendered view)

(after rendering with F12)

I'm not getting that for some reason. Please see pic

Also there is a weird message i circled that i dont see in your picture

sorry if i didnt reply properly. I couldnt attach an image via comment


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render engine will not change from workbench
I am doing an animation project and i used workbench to quickly render out the animation (i rendered to PNG sequence). However when i try to final render still images for testing all i get is the workbench version of the render. I've tried cycles and Eevee with no luck.
When i set viewport from shaded to rendered using Cycles or Eevee i get proper rendered viewport as normal.
Old files work as expected as well so i don't think blender is broken :). so its something i did when using workbench?
If i copy and paste all geometry lights and camera to a new empty scene. all is well. Its so weird.
Thoughts? Thanks in advance!
Tony

Version 2.83 i'm guessing?

Does this help? https://blender.stackexchange.com/questions/5285/blender-is-rendering-an-older-version-my-project

OH YES!!!! thank you! Makes perfect sense that it works when copying and pasting to a clean blend file. and yes i'm on 2.3 version


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Node editor connections are not curvy
I'm using Blender 2.81. I tried reinstalling the Node Wrangler extension multiple times. Everything works fine, but it only displayed those bendy/curvy connections/links following the first install after a fresh setup of Blender 2.81.
I couldn't find any option to fix this in the preferences.

As I was throughly looking through preferences one last time lest I post a stupid question, it appears that the option is not related to node wrangler alone: it's a theme option for all node editors called "Noodle curving".
So links are really called noodles.

so maybe explain more clearly how to set it   ;)


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Strange fluid sim behaviour
Good day.
I found another member had the same prob twi years ago. Maybe someone can help me this time.
THe prob is the following:
I got (now) a simple setup with a bowl (acting as fluid->obstacle) and some water in it (fluid->fluid). The scene is surrounded by a cube (acting as fluid->domain). Last object is the camera.
I reduced my scene to only this four objects to reduce possible error sources.
Now when I'm start the baking process, this is the first frame after the simulation starts:

It is not my first fluid sim and I never had such a problem before. Setting are pretty much default. Any hints on this?

Is your domain big enough to encompass all objects? Do all objects have applied rotation and scale?

Yes and yes! Domain is big enough, Rotation & Scale applied.

I just tried a similar setup... it works, so it could be just your file/setup: can you share it on http://blend-exchange.giantcowfilms.com/ and post the link here?

I tried to upload it to Blend-Exchange, but it caused errors. I uploaded it to my google drive: https://drive.google.com/open?id=0B68Wl-5lW3EkUkEzZWM3MHBrWDg
btw: this is another file where I just tried to do everything again in a complete new file. Behaviouir is just the same. So I must have done something wrong that I am constantly overlooking.

YES! I solved the problem. Thanks to sardipax! It was very simple: the normals ofc were facing inwards bcs. I created the water mesh from the bowl/glas. Flipping the normals solved this issue.
Thanks for everyone who took care here.
Damned what a wasted night just because of such a simple mistake ... ;-)


text:
Strange indication to a missing UV-Map?
Good day.
For some reason I see a strange purple reflection in my scene. I know that this is usually an indication to a missing UV-Map. But I unwrapped every object in my scene. The background is transparent with an image added in the compositor.
Do you guys have some ideas where this might come from?

Purple (magenta or more known as pink) is the indication of missing texture, i.e. image file accessible to Blender for opening. As those bolts seem to be glossy they could reflect it from environment hdr setup as pink can be also seen in the bottom right. Check if hdr image's loading correctly. https://blender.stackexchange.com/questions/5368/why-are-all-the-textures-in-my-file-pink

Thank you for your answer. The image is visible in the background as it is supposed to be, BUT: I indeed forgot that I tried to use a world-background when I started the scene. And that was - as you mentioned - the problem! Thank you very much!

As written in the comments - I'm just getting old.
Gone is the purple reflection:

[edit]
Sorry for the missing details. I forgot that I wanted to use a world background image at the beginning. Therefore I changed the surface type to "image" without actually asigning one. That caused the reflections.

It's advised here to include some details into your answer without relying to comments; as of now the answer itself doesn't tell anything why is it answer. Add screenshots of setup and several statements elaborating on the topic.


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Duplication offset ignored in reflections
Good day.
I got a weird problem. Again. I created a tunnel scene where I am using a path to create the lamps inside the tunnel. I am using an offset of 4 to reduce the ammount of lamps on the wall.
But in the reflections (water puddles) on the ground, the offset seems to be ignored. It therefore relects 4x as much light as visible in the scene.
You can see the effct in the attached image.

Where did I make the mistake?

Looks ok to me, those are not settings that can be different between direct rays and reflection ones. Are you using lamp objects, besides the modeled meshes on the wall? Those look like point light reflections.

Your only mistake is your expectations of what will get reflected at certain locations. The reflections under the point of the red arrow are from the farther end of the tunnel as it curves. See how the reflections curve with the tunnel. If you hold a mirror in front of your face and parallel to the floor, you will not see your face, you will see the roof at the far end of the room.

Yes - the reflections are point lights. I am not done with the scene yet.
I understand. So I will change the angle a bit to get it somehow closer to my expectations.


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GPU view port render slower than CPU
I have a dual GTX-1060 in my computer running Ubuntu 18.04
NVIDIA driver installed is:
NVIDIA-SMI 450.80.02    Driver Version: 450.80.02    CUDA Version: 11.0
When I set GPU render on blender 2.83 official build, the GPU render is fast
However on blender 2.90+ the GPU render is slower than the CPU render.
I tried building my own blender as well as downloading the nightly build. Both have the same issue.
Anyone know why? Or have ideas what to look at?
thanks

I'm going to suppose you have activated one of the cycles render devices under system in the preferences panel, if you have already, it's probably a hardware issue

Yes. I have. I think I found out the culprit. I had "Distributed memory across devices" checked. And for some reason that slowed down the GPU render. When I unchecked it, the GPU view port render performance improved. Interestingly enough that option is not available in 2.83. Again my system has 2 GPUs. Any idea why that option slows down performance?


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CG Cookie Flex Rig Linking Problems
I've been trying to modify CGCookie's flexrig to work in blender 2.8.
The model itself works fine in the main file. However, when I link it into another file, I start seeing strange behaviour.

The bone shapes meshes are visible and overlaying the actual bones, such that you can't see the shape colours.
When I import the rig_ui script and run it, the bone shapes lose their modifiers. Some of them have a mirror modifier, so half of the mesh appears
The rig itself is a bit messed up. For example the IK foot, would bend the knee backwards instead of forward. That problem doesn't exist in the original file

You can get my modified file here: https://www.openmovie.org/resources/blend-files#h.p_Jj8Qih-ybkfZ
I show a video of what's happening when I link here: https://www.youtube.com/watch?v=vhUWy5b7xQs
There are some errors and circular dependencies:
Dependency cycle detected:
  OBrig/Parameters Component/DRIVER(pose.bones["cheek.R"].location) depends on
  OBrig/cheek.R/BONE_LOCAL() via 'RNA Target -> Driver'
  OBrig/Parameters Component/DRIVER(pose.bones["cheek.R"].location) via 'Driver -> Driven Property'
Dependency cycle detected:
  OBrig/Parameters Component/DRIVER(pose.bones["cheek.L"].location) depends on
  OBrig/cheek.L/BONE_LOCAL() via 'RNA Target -> Driver'
  OBrig/Parameters Component/DRIVER(pose.bones["cheek.L"].location) via 'Driver -> Driven Property'
Dependency cycle detected:
  OBrig/root/BONE_CONSTRAINTS() depends on
  OBrig/body_variants/BONE_DONE() via 'Copy Scale'
  OBrig/body_variants/BONE_READY() via 'Ready -> Done'
  OBrig/body_variants/BONE_POSE_PARENT() via 'Pose -> Ready'
  OBrig/root/BONE_DONE() via 'Parent Bone -> Child Bone'
  OBrig/root/BONE_READY() via 'Ready -> Done'
  OBrig/root/BONE_CONSTRAINTS() via 'Constraints -> Ready'
Detected 3 dependency cycles
ERROR (bke.anim_sys): /home/ashehata/Software/blender_git/blender/source/blender/blenkernel/intern/anim_sys.c:4160 BKE_animsys_eval_driver: invalid driver - modifiers["Mask"].show_render[0]
ERROR (bke.anim_sys): /home/ashehata/Software/blender_git/blender/source/blender/blenkernel/intern/anim_sys.c:4160 BKE_animsys_eval_driver: invalid driver - modifiers["Mask"].show_viewport[0]
ERROR (bke.anim_sys): /home/ashehata/Software/blender_git/blender/source/blender/blenkernel/intern/anim_sys.c:4160 BKE_animsys_eval_driver: invalid driver - specular_hardness[0]
ERROR (bke.anim_sys): /home/ashehata/Software/blender_git/blender/source/blender/blenkernel/intern/anim_sys.c:4160 BKE_animsys_eval_driver: invalid driver - empty_draw_size[0]
ERROR (bke.anim_sys): /home/ashehata/Software/blender_git/blender/source/blender/blenkernel/intern/anim_sys.c:4160 BKE_animsys_eval_driver: invalid driver - pose.bones["face_variants"]["upper_lip_scale"][0]
Info: Deleted 1 object(s)

Any help would be greatly appreciated... Kinda running out of ideas.


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Bake a texture WITHOUT doing UV Unwrapping?
I am a SketchUp user by trade, but one thing Sketchup can't do is export UV texture maps for objects such as you have to use for .obj fils in something like Tabletop Simulator, which will only import one model file and one texture file - so I have to use Blender. (Just to be absolutely clear as to my terms by 'unwrapped texture map' I mean something like this wherein a complex object is unwrapped onto a single plane and all the various materials and textures are shown in an 'unwrapped' state so they can be wrapped around a model and make it look painted)
So: if I export my Sketchup file as a Collada file it imports into Blender just fine - my textures are all in place, the model looks like it did when I exported it, and I am perfectly capable of lighting and rendering it. But that's not what I want to do - I want to make that flat, square UV texture map. Unfortunately, the UV maps looks like any other UV map before you unwrap it - a big squiggly mess.
SO the obvious thing to do is to select my model, go the edit mode, select everything, do a SMartUV unwrap - same as I would for anything else in Blender.
Unfortunately, that immediately ruins all my textures. Everything becomes instantly distorted and all my careful texture dimension work goes out the window. I've got a UV map, but now all my textures are wrong.
So there was a suggestion that all I need do is to 'bake' the textures as they were imported, but that seems to come with its own host of problems, and all the tutorials I can find are all about baking procedurally generated Blender materials - not textures imported externally from another program.
TO SUMMATE MY ISSUE
I have a model built in sketchup. The model contains multiple different textures - like a house with brick walls, window glass, roof tiles etc. I can import this into Blender as a Collada file, but the moment I unwrap the UV, all the textures in my model instantly distort. (E.G. a wall with many bricks sees the brick texture expand so that each brick is nine feet long and blurry as heck).
How can I unwrap my model without affecting the texture size. Alternatively, is there a way I can bake everything into one nice square/rectangular texture map for use in a game WITHOUT having to unwrap the UV?
Can anyone here help me? I want to take my imported model and create a texture map preferably without having to completely repaint the entire model. What are my options?
Thank you in advance.

you can create a new UV Map in the Object Data panel > UV Maps, and use it as the UV that will receive the bake

The moment I create any UV maps my texture scaling is instantly destroyed. The model does not import with a UV map - one has to be created first, and therein lies the issue. If I create a new UV map in Object Data, go to Render Properties - > Cycles - Bake, I just get an error message about needing a UV map.

could you please share one of your objects? https://pasteall.org/blend/


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Should I use the bool tool after I have already started sculpting?
I'm defiantly a noob to Blender and I am very cautious.
I know that that one of the general work flows for creating a character consist of forming spheres to create a base mesh, then joining the spheres together, and then sculpting to add further detail and etc. And currently that is my main approach. But I was wondering about what would happen if you bool tooled everything together, then sculpt, then bool tooled a new mesh to the sculpt. Can you actually do that? Or would it mess up the mesh somehow? Does it even matter?

I think the spheres way is how simpsons are drawn. I can only imgagine using dyntopo to connect spheres, anything else I would suggest roughly model the shape you're after and then start sculpting. I've used boolean to insert feet into an irregular model, but that was dyntopo and I didn't care how unclean the seams were.

Yes you can use boolean to add some shapes to your object and sculpt again

Thanks everyone for the responses!


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How to track a 6km long road. How to dissolve markers
I need to track a 6km long road. Its 4k footage made by a drone and I want to stabalize the footage along the way. When I stabalize and play the footage, and one tracker goes off the screen (because it has reached its end of the frame), the screen 'jumps' tot the next tracker/marker..

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

i have 4k footage filed by a drone. it needs to be stabalized. The road is 6km long. How can I stabalize a 6km long road...


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Can I modify a rigify rig to add a head after generating it?
So a while back I rigged a model using rigify in blender 2.8, and deleted the face bones, as it was way too complex for what I wanted to do with the character. Flashback to now, and I've spent hours making animations for the model, but would now like to add facial animations to go along with the body one's I made. Is there anything I can do to add a face rig, because it doesen't seem like I can modify the rig in edit mode, the new bones I make do nothing? I'm ok with rigging a new character but I would like to be able to save the animations I made with this rig? Thanks so much I would apricate any advice.

https://docs.blender.org/manual/en/2.81/addons/rigging/rigify.html
From the manual:
Nondisruptive re-rig
If the generated rig doesn’t fit all the features you need or, for example, you decide to add something more to your character (like a sixth arm or a tail), you can re-generate your rig without losing your previously generated features and your animation data.

Thank you! This worked great!


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Rigify Generate Rig: index out of range
I'm using rigify to rig a character I've setup, the weight paint and movement all works fine but rigify is generating an error "Generation has thrown an exception: list index out of range" when I click generate rig. I've included a link to the blend file if that helps as I can't figure out whats causing the error and haven't been able to find an answer on Google. I've gone cleaned up my model and had a look through the bones but can't find any issues. I have changed some bones from the default rig if that's an issue so not sure if I need to do something extra to update rigify. Any help would be greatly appreciated!
https://drive.google.com/file/d/1oVaTbJNIyH9ekEXSVOAklCkZe1uhcKSn/view?usp=sharing

You have deleted a bunch of bones that rigify can't work without. The problems are just everywhere, legs, spine, head. Any one of them could be throwing the exception.
I have two suggestions. If you want to learn how to use rigify correctly, I have a series of videos here:
https://www.youtube.com/playlist?list=PLdcL5aF8ZcJv68SSdwxip33M7snakl6Dx
But for the lego character, a custom rig may be better. Here is an AWESOME tutorial:
https://www.youtube.com/watch?v=hIaSCV9AUvI

Awesome thanks for the pointers that's really great help. I did watch a blender tutorial that did say you can remove them but I must have removed too many!


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How do I distribute objects along an edge loop?
I am modeling a leather chair with a curved back. It is like a chaise lounge.  I hame modeled the wooden frame and the curved leather cushion.  I modeled the cushion and on the back side created an edge loop then extruded the leather band for the tacks and created another edge loop on this bad extrusion for the tacks to align.  I have modeled the tack as an object and need to distribute them along the edge loop.
I am moving from 3DS MAX to Blender 2.8. And can not figure out a way to get this to work.  Any suggestions would be appreciated.
I thought about converting the edge-loop to a curve, but I cant find any way to convert it.  I trued painting on a path but the tacks end up way offset from the surface. It seems there should be a simple way to do this.
I seldom find myself completely stumped but this is one of those times.

This can be done using Instancing and an Array and Curve modifier. and also by instancing a loop and a mesh object.
Curve method

In Edit Mode select your edge loop (Alt select an edge or vertex) and duplicate it: press Shift + D, hit Esc and separate it By Selection by pressing P.

Go into Object Mode, select the loop and press Alt + C to Convert it, choose Curve from Mesh/Text.

Add a Plane object, move it to the location of your tack object and scale it roughly to the size of your tack object. Then parent the tack object to the plane: Shift select the tack and the plane, in that order, and press Ctrl + P and choose Object(Keep Transform). After that select the plane object and go to Properties > Object Properties > Instancing and click on Faces. Make sure that the box next to Render Instancer in unchecked.

With the plane selected go to the Modifier Properties tab in the Properties window. Add an Array modifier to the plane and (later) change the values per your preferences. Change Count for number of tacks, and Offset value for the distance between them. (Best to already put some values in the fields, so you have something to work with.)

Then add a Curve modifier to the plane object, and as a target Object choose your edge loop curve object. Move your plane/tack array to your curve object and move it around until it looks relatively fine and in position.

If thing are moving in a weird and unexpected way, make sure the axis of the Offset value of the Array modifier is the same as the Deformation Axis of the Curve modifier.

Why the plane and the instancing? Why not put the Array and Curve modifier directly on the tack object? It would deform your tack object if you change the position and/or rotation of the array, curve, and the vertices of the curve. Beneficial sometimes but possibly not in this case.
Some fine-tuning:

If your tack object is to far away form the curve move it closer : ). Or alternatively scale the curve a bit bigger in Edit Mode.

You might have to simply move the vertices of the curve if tacks are to deep, not deep enough, or misaligned.

What if some (non spherical) tacks are facing the wrong way? Select your curve, go into Edit Mode, select the vertex or vertices near these tacks and press Ctrl + T to change the tilt of the vertices, and consequently rotating the nearby tacks.

If there are more vertices in your curve then you like to handle and you want to simplify things you can easily reduce their number. Select the curve in Edit Mode, press F3 (the default search hotkey), type "Set Spline Type" and choose Bezier. (Or click on Curve in the header to do the same thing.) Then hit F3 again and type "Decimate Curve" and enter a value between 0 and 1.

A sloppy execution might look something like this:

EDIT:
If your tack objects are spheres for instance and their orientation does not matter at all you can do something similar but a little easier.
As mentioned above, with Instancing you can show a child object for every face of the mesh of its parent object. But also (if you choose the Verts instancing option instead) for every vertex of the mesh of the parent.
Mesh method

In Edit Mode select your edge loop (Alt select an edge or vertex) and duplicate it: press Shift + D, hit Esc and separate it By Selection by pressing P.

Go into Object Mode, select the loop and press Alt + C to Convert it, choose Curve from Mesh/Text.

Press Alt + C again to Convert it back, choose Mesh from Curve/Meta/Surf/Text.

Why this back and forth with conversion? It will cause a somewhat even distribution of vertices along the length of the loop. (there are other ways, but i think will do in this case.)

After that select the loop (which is now a mesh object, not a curve) and go to Properties > Object Properties > Instancing and click on Verts. Now make the Tack object a child of the loop object: select the tack and the loop, in that order, and press Ctrl + P and choose Object(Keep Transform). The tack should appear for every Vertex in the loop mesh.

Fine-tuning:

What if the tacks are to close together? Select al vertices of the loop in Edit mode. Do Select > Checker Deselect, press X or Del and choose Dissolve Vertices.

What if the tacks are to far apart? Select al vertices of the loop in Edit mode. Press F3 (default search hotkey), type "Subdivide" and add a value for Number of Cuts in the bottom left properties panel (or hit F9).

I tried this and it did not work. No matter what I do the Aligned Planes are way above the curve.  Nothing seems to make them align with the curve.  If I was in 3DS MAX i would do a LOFT. but I do not see an equivalent function in Blender.  Am I missing it?

I was under the impression Loft in 3Ds Max does something like changing the bevel depth value of a curve in Blender (Properties > Object Data Properties > Geometry > Bevel > Depth) but with more control over thickens in various places. This gives me the impression your tacks are not nails but just spheres, or would be bulges in the 3ds max loft. I'll edit my answer accordingly. (If they are not spheres but tacks like nails, then please add a image so i can see what you meant with "above")

I'm done editing my answer, I hope you can get it to work now, If not, let me know. : )


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Texture Painting - stencil disappeared
I've been working the texture painting lesson in the apple tutorial by CGBoost.  Everything was working fine.  The stencil painting was working great and then the stencil disappeared.  I don't know what I did to make the stencil image disappear or how to get it back.  In watching the tutorial, there is a display dropdown in the draw tool.  I do not have that.  I am using 2.83.  When in the tutorial the alpha was reduced to 0 the stencil image disappeared and reappeared as the alpha was increased.  Since I don't have that drop down I can't do that.  It feels like my disappearance has to do with the alpha of the image - but how do I get to it.  Thanks.


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Cycles Renderer: ColorRamp ignores previous Set Alpha node
In Cycles, I would like to separate out an element from an image, and apply a color ramp to it before merging it back. After separating out the element however, the color ramp still operates on the original (unseparated) image. Why is it doing this?
Done so far:
I separated out an element of the scene via ID mask, and then applied the mask to the original image with Set Alpha. When I apply a color ramp to the second image, not only does it apply to the cropped out image, but it seems to retain information from the very first input image, as you can see from the Viewers in the image below.
Tried the same setup in Blender Internal but the result is roughly the same.
Is this a bug or am I missing something about how nodes/cycles works?

This is normal. Colorramp use only those colors what you adjusted in it. When you adjust the colorramp's colors you can adjust the alpha too. But you don't have to do anything with it, just plug the "Render Layers's" alpha output to the last "Viewer's" alpha input.


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Problem using Multires sculpting!
I am trying to Sculpt a character using multires and i tried to shape general forms in lower Sub and move on to higher subdivisions step by step but after forming the basic shape that I wanted subdividing cause this artifact!

Notes:
-Rot scale applied
-Base mesh did not changed in edit mode
-apply base makes it worse
Does anyone have any ideas?
Thanks for your time!

i have the same problem as you. Blender 2.8 from 11 oct. My model's eyes and hands becobe mess after i make "Apply Base". Do you found any solutions yet?

The problem was modifying overall shapes of a pre defined basemesh using "grab" brush.
changes in major shapes of a basemesh using grab brush creates artifact using multires
subdivision


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Underlying tiny checkerboard on painted object
I have my object set up to paint, but as soon as I paint on it, a tiny checkerboard pattern shows up under the paint color?

I figured out what was wrong: I needed to delete pre-existing textures in the texture tab.


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Easier way to convert text to mesh for keyframe baking with animation nodes
Below is the animation node set up for a timer that just alternates between 0s and 1s. I would like to bake keyframes for this animation so that I can render the entire animation on sheepit.
But apparently, '0 s' is a text and so I can't do it. Is there a way to make a simple modification to the node tree below or do I have to make an entirely new node tree to be able to bake the keyframes?

Apart from baking to keyframes (which is quite limited) you can store values in Object ID properties, but .blend file will become bigger. See here: https://blender.stackexchange.com/questions/130035/how-to-save-animation-nodes-cache-without-baking-to-mesh

You may just create two meshes and hide/show them in an alternating pattern. Would that work for you?

Yeah, I guess that would give the same effect. Thanks.


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Making a spherical gradient that becomes transparent towards the outside
I want to know if there's a way to create the following material: A spherical gradient that is red in the center and gets transparent farther away from the center.
I want to apply such a material to a plane object.

https://blender.stackexchange.com/questions/65706/how-to-make-a-good-glow-effect-around-a-sun/65711#65711 https://blender.stackexchange.com/questions/70576/transparency-masking-see-through-an-outer-sphere-and-see-inner-sphere-in-true/70619#70619

As Rob suggests you can use a Gradient node in Quadratic Sphere mode:

You will have to make changes to get it how you want.  I'm not sure what changes exactly, sorry, but this might work for you.  GL

Someone will probably have a better/simpler solution.  I just had this image handy, lol.  You can Google search for "gradient material in blender" and switch the search type to Images, you'll find something that works : )

Yeah thanks, this was almost what I wanted actually. Except that instead of the transparency being in the inner part of the circle I want it to be on the outer part. In short exactly the inverse of the above transparency effect. I tried to google it, unfortunately I didn't get any images corresponding to what I wanted. Do you know how to achieve the inverse of the above?

Also look at the "Gradient Shader" set to "Quadratic Sphere"

Flip the transparent shader and the other shaders : )  Oh and it works in Cycles, as is, but for Eevee, you need to set the material blend mode to Alpha.  GL

As rob said, you can mix a shader with a transparent shader and use the Gradient Texture node as the mix factor.  Just remember for Eevee to change the material settings so it uses the alpha.  It seems to work well : )


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Want to render animation nodes text animation on sheepit
I have a blender animation where I have used the trim text feature of the animation nodes add-on of blender. However, when I upload it to the render farm, those parts don't render out. I've been told, on blender stack exchange, that it's because the render farm does not have the animation nodes add-on installed. I would however appreciate it if someone suggested a workaround to this.

Yes, it seems to be exactly what I was looking for, thank you. But the solution on that page doesn't seem to be working for me. Could you possibly explain what's being done there with all those nodes?

Glad I could help. First, did you take a look at the documentation for the nodes used in there? Documentation might make things clearer for you. Let me know if you are still having trouble.

I went through the documentation and was able to recreate it for my text animation. However, I still do not understand how doing this enables us to "keep the animation but remove the node tree". Do we have to manually add keyframes after doing such a node setup?

In the overview panel, there is an operator called Bake To Keyframes, this will create the keyframes automatically.

I've run into a problem. If we use the separate text object and convert the text to mesh, I'm not able to reduce the size of the entire mesh(converted from text). If I hit 'S' and scale it down the letters just come closer together. How to resolve this?

You probably encountered the famous "Only Origins" problem.

Yeah, thanks, that's it. But now this weird thing's happening. In my current blend file, ticking and un-ticking the manipulate center points button does nothing to my text. However, in a new blend file, it's working the way it's mean to. Is there something I'm missing?

I am not sure what the problem is here.


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Output either 0 or 1 for every 24 frames using animation nodes
I want an output of 0 for the first 24 frames, 1 for the next 24 frames, 0 again for the next 24 frames and so on.
That is, at frame one the output text is 0 and after 24 frames the output changes to 1 and after the next 24 frames the output changes to 0 again.
How do I do this using animation nodes?

Here is an example,
1) Repeat node is giving values from 0 to 47 i.e 48 when the rate is 48.
2) Because repeat node also count 0, so I have substracted 1 from frame.
3) Then using compare boolean and switch nodes we can choose 0 for 0-23 frames (24) and for next 24-47 (24) frames, 1.
4) Last I use float text node to convert float to text and text object output to text-object.

Okay, so after some thinking I found the right nodes and it wasn't as complicated as I thought it to be. I've attached a picture of the node tree.


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Can I use a panoramic rendered Blender scene as environment texture?
I'm trying to create a VR animation of an experiment being done in a classroom. The render times are through the roof if I render each frame of the animation, setting the camera to panoramic view. Can I render the classroom scene just once (setting the camera to panoramic), then use that as an environment texture for the rest of the animation in which the camera just focuses on a table where all the experiments are going on.
Will this reduce my render time?
Please help!

This should definitely be possible. Pre-rendered backgrounds are a pretty common technique for speeding up rendering times.
The only issue to be aware of with static backgrounds is that you need to be careful with camera movement as you will not get the parallax effect. I suspect that this is likely to be more obvious in VR scenes due to independent head movement/viewing angle (you can just get away with panning a few layers over each other at different rates). How noticeable this effect is will depend on the distance between the camera and the nearest object in the background, the variation of object distances in the background and the amount of camera movement.


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Does blender recognize the same background if present in multiple frames of an animation?
So recently, my friend and I were talking and he suddenly just put the idea out that if we render an animation of say 60 frames that has a fixed camera and only a specific component like,say, a cube rotating, blender does not render the background scene for  every subsequent frame after it first renders the background scene but rather only the cube whose rotation changes.
Is it so?

At least in cycles, no, and in other renderers, very unlikely.
In order to get physically accurate light transport you can't make assumptions like this, and Cycles definitely tries to be accurate in this regard.
Think about it, where does the computer decide where to cut from background to middle to foreground. How does it deal with reflected light or shadow onto the background? The only way to accurately figure this out is to trace the light rays, at which point you are rendering it.
If you want a static background, you render it separately and either composite it, use an emit only background pane or environment texture. This is generally the preferable solution as it is both simpler from a developer support perspective, and also puts control squarely in the artist's hands.


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Particles not rendering on sheepit render farm
I uploaded a blender file with particle animation on sheepit. However none of the particles actually appear. Rather, the particles just stay at the source(i.e the emitter).
On searching, I realized we had to bake the animation. So I did that, and zipped all the baked '.bphys' files along with the '.blend' file and uploaded it again on sheepit. But I'm getting the same results.

I would try to leave the baked data in the file instead of baking to disk. Baked data should be saved with the file if Disk Cache is disabled under Cache in the Particle tab of the Properties Editor as far as I understand.

Thanks a lot, it worked ! My animation is halfway through on sheepit and the particle animation is coming as it's supposed to.

@MartinZ you should post that as an answer.

I had not tested this and was unsure it would work. Posted as an answer now so other people can find it.

The solution here seems to be to leave the baked data in the file instead of baking to disk this way avoiding problems with reading the files on the render farm. Baked data is saved with the file if Disk Cache is disabled under Cache in the Particle tab of the Properties Editor:


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Facial tracking
I've been playing around with facial tracking. Placing markers on my face, then tracking it in blender. Once I hit "Link Empty to track" It creates the markers and they follow my facial movement. Each marker has a "follow track" constraint. I'm trying to resolve that into key frames. I hit the "Constraint to F-curve", but nothing happens. I don't see an error message at the top and no keyframes are created for that marker.
Is there a step I'm missing?
Thanks in advance.

Does the "current cache to bake" button help? I often forget about it when I do physics, and it tends to give similar symptoms.

I believe that's for physics simulation. I don't have any physics. I simply added some trackers to footage. Each tracker has a follow constraint, but I can't get that resolved into keyframes.


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add scratches to metal material
I'm working on a short with a CGI robot. I found this:
https://www.youtube.com/watch?v=RUmamyB-C6o
I'm trying to achieve a similar look with the scratches. The node setup he has in the video, looks quiet complex and I'm not sure how to go about doing this.
Is the best approach to add metal scratches is to create a UV map, that I can add to the metal, sort of like what I did on the face? Is there a different approach?

Done. I added a more specific question, regarding achieving a realistic metal scratch look. I don't want to apply all over the body of the robot, but in specific areas. And I'm trying to figure out the best approach to do that.

Great, thanks for all the pointers. Will take a detailed look at these examples.


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Copy NLA tracks from one armature to another
I've been doing my animation on a low poly model. And now I want to transfer the animations to the high-poly model. I'm doing the following steps:
1. Link the high-poly model into a new blend file
2. Link the scene from the animated file
3. copy transforms from the low-poly to high-poly
4. Apply the actions from the low-poly to the high-poly
5. Rebuild the action strip sequnce in the NLA editor for the high-poly model.
It's not hard but it strikes me as common workflow, where you wouldn't necessarily want to animate a high-poly model, so you work with a lower res version. Admittedly, if the model was designed properly it's mesh wouldn't be too high-poly, and would use a subsurf modifier. But alas, I'm not a modeler and this is a model I bought that worked for me.
Is there a way to apply the NLA editor sequence of the low-poly model to the high-poly model in less steps. Almost, like saying replace the low-res model with a high-res model, and it'll just do it.
I'm aware of this: How can i copy NLA Tracks from one armature to another?
But I don't have the cycles (no pun intended) to go down the path of fiddling around with python scripts at this stage of the project.
thanks

Sounds like writing a python script might be easier than adjusting your files. Ideally you want to setup your files to support hi/lo versions. If you look at the sintel files, both the hi and lo poly meshes are in the same file and use the same armature, the animation files animate the armature and can easily switch between the lo and hi poly mesh.

both my lo and hi poly meshes use the same armature. But I didn't include them in the same .blend file initially. But I did link them (Ctrl+Alt+O) to the same file. That's how I'm able to transfer the actions to the hi poly mesh. But since I use the NLA editors to combine multiple actions, I had to rebuild it for the hi poly mesh. That's the part I'm wondering if there is a way to share the NLA editor strips between armatures. How did they do it in the sintel files? I have to find those files and take a look.

In the sintel files two groups are created hi and lo - when you link from an external file you import the group and an empty is created, the dupligroup settings on the empty switch between the two meshes using the same armature and animation data.


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Bad Camera solve in blender with forground motion
I have a scene I'm trying to track, but I'm unable to get a good camera solve. I end up with errors above 1.46. The issue with that scene is that there is an actor moving in the scene. So I'm tracking the half of the frame which the actor doesn't cross. Is there a specific strategy to get a good camera solve with scenes like this?
Here is a link to the scene I'm trying to track. Any suggestions would be great.
https://drive.google.com/drive/folders/0By7_pLesGvS0VkFodE9DMXRHNU0?usp=sharing
thanks in advance.

this related question may help: https://blender.stackexchange.com/q/42329/19287

Thanks. I'll look at those. But I think what's different in my case is that I have a foreground moving actor. So I'm unable to track the entire frame, just the portion of the frame which the actor doesn't overlap with. Would tracking half of the frame represent an issue? IE, the track won't understand the motion of the camera correctly?

I ended up using Voodoo, which was remarkably accurate, and completely automatic. It's a good alternative if one can't get an accurate track from within blender.