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What is the technical difference between softbody and cloth simulation?
They are definitely different, but soft body simulation is very slow compared to cloth.. why?

In short, soft bodies are compressible while cloth is not. All other features are the same.
However, this makes a huge difference in computational speed. To better explain this, I will use an extension of the metaphor CharlesL used in his response.
A Cloth Simulation essentially models the object as a bunch of balls (vertices) connected to each other by fixed-length rods. Thus, for computational purposes, the simulation can treat the internal distances between points as a constant, and only has to calculate interaction with other objects.
A Soft Body Simulation, on the other hand, models the object as a bunch of balls (vertices) connected to each other by springs. So now, not only does Blender have to compute the interaction of the object with other objects, but also has to compute its own internal reaction and the spread of force applied at one point across all of those little springs, which is much more complex.
I don't know the exact complexity of the algorithms Blender uses for these simulations, but it's essentially the difference between a linear relationship and a differential equation.

According to Todd Koeckeritz (Blender Cloth Developer), the Cloth Simulation uses a Spring Network (not fixed-length rods). More information can be found here: http://blender.stackexchange.com/questions/8247/on-what-cloth-simulation-model-is-blender-cloth-physics-based/

Also, the "Structural" and "Bending" parameters in the Blender Cloth Panel represent the Spring Network's stiffness, as seen in the Blender Cloth Manual: http://www.blender.org/manual/physics/cloth.html

Additionally, Blender uses Provot's Cloth Model. In Provot's model "all springs have a natural length non equal to zero but they remain nevertheless intrinsically linear springs."

However, Kass/Pixar did come up with "fixed-length" springs similar to Provot's structural springs. Kass reads: "With only fixed-length springs along the mesh edges, the simulated clothing can undergo arbitrary skew without penalty. One way to prevent the skew is to introduce fixed-length springs along the diagonals. The problem with this approach is that strong diagonal springs make the mesh too stiff, and weak diagonal springs allow the mesh to skew excessively."

More completely, the Provot model states: "everything happens as if the springs were classical springs up to a certain deformation rate and quasi rigid rods above this deformation rate"

I'm not sure about speed and optimization but there are some differences between the two. Here is what the documentation says about the softbody simulator:

A Soft Body in general, is a simulation of a soft or rigid deformable
object. In Blender, this system is best for simple cloth objects and
closed meshes. There is dedicated Cloth Simulation physics that use a
different solver, and is better for cloth.
This simulation is done by applying forces to the vertices or
controlpoints of the object. There are exterior forces like gravity or
forcefields and interior forces that hold the vertices together. This
way you can simulate the shapes that an object would take on in
reality if it had volume, was filled with something, and was acted on
by real forces.

So basically the soft body measures where each vertex should be pushing the vertices around it. Kind of like a bunch of opposing magnets connected by string.
The cloth simulator works more along the lines of each vertex having mass and simply falling and folding without much care as to the other vertices around it (except of course for collisions). It's more like a bunch of marbles connected by string.
Soft bodies are generally better for enclosed meshes (i.e. no non-manifold edges) and things that will bounce or jiggle or conform to its surroundings.
Cloth is better for non-manifold meshes that will fall and collide with other meshes. It works better with things like clothing, flags or bed sheets.


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When is acceptable to have disconnected geometry?
Some times it's easier to add a quick sphere and move it so it intersects a part of an existing model rather than trying to connect the existing model to the sphere.
When are these kinds of shortcuts acceptable (or not) for good topology?

This technique has lots of advantages, the biggest of which is of course speed of modeling. There are also some drawbacks you might want to consider:

Stacking is troublesome if you need bevelling. The intersections will stay sharp, no matter what.

Freestyle won't produce the result you're after. It uses face boundaries to find edges and there are none.

In the past, Blender sometimes had trouble to precisely calculate the intersections, resulting in a jagged appearance. I haven't noticed that lately so it might be fine.
If you deform the surface, the object might move relative to one another, resulting in a shift of the edge. Or in Z-fighting.
Transparent materials will show that you tried to cheat. Nothing against cheating in 3D as long as you can get away with it. The left image is how it should look, the right is how it looks if it's stacked. This effect gets worse when you rotate around the object.

If you don't use it for joints or movable parts but just for speeding up the modeling, and you don't trim the parts inside the model, it always results in unnecessary geometry. Depends on the case what's more important. But even with trimming, it's still faster than manually connecting the detail or cleaning up boolean artefacts.
Adding small details has the advantage of not distorting the big geometry which can be quite time consuming to repair or plan in advance.
Tools like the Loop Cut will ignore the detail  when you work on the main mesh.
It affects your UV mapping workflow.
One of the biggest factors still is screen size. Extreme closeups will reveal possible problems. If it's just a small detail, you can employ a lot of simplification techniques, saving time.

Thanks for your answer :) What about any pros/cons for adding medium/small details in hard-surface modeling?

Re: In the past, Blender sometimes had trouble to precisely calculate the intersections, Some graphics cards have bad depth precision, Or you may have clip-near/far set to large, irrespective - this is a general precision issues and not really Blender specific.

In the viewport, yes. But it also happened in rendering, if I'm not totally mistaken, I think when the camera settings for clipping were off. And this seems to have been fixed.

Some reasons, off the top of my head:

Style:  Maybe you are going for an early Pixar from the 90's look, with some primitives slapped together, I'm not gonna judge.
Full rotational potential: If you are building, say, a robot with ball and socket joints, it would make sense not to connect the meshes.  There is a chance any part of the sphere is visible, so you do not want to go and connect the two at any point.
Interchangeability: Dota 2, the game, has characters that are made up of many different meshes, so the game can swap out parts at will.  Similar things may need to happen if you are making a game or something that another program needs to modify.  Guns and Characters will not be connected, as a more broad example.
Speed:  Sometimes it is just plain faster for you to model and rig and animate if the meshes don't need to connect at any point.  Hair, spikes, that sort of thing are legitimate reasons.
Modifier dodging: Sometimes you need parts of a mesh that will not be affected by an object-wide mesh modifier.  Splitting the item away and parenting it in place is a quick and easy solution (I realize that there are vertex weights, but that is imperfect and on a modifier-by-modifier basis).

Thanks for your answer :) What about any pros/cons for adding medium/small details in hard-surface modeling?

From Experience, it can gets very unwieldy after a while.  There is overhead for each stand-alone object, and after about a hundred or so, my computer starts to get really slow, but YMMV.  Just keep in the back of your mind that you will need to keep it all organized.

If you make each part into a separate object, then yes. But e.g. making a car with separate parts for the different panels (hood, doors, roof, etc.) you may want to keep them in the same object in some cases. (BTW, sweet model :) )

source: Stack Exchange

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

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Is there a way to keep hair childeren and edit the mesh?
Editing a mesh after adding hair particles will mess up the hair (I assume it's because hairs are placed based on vertex order/indexes which change when the mesh is edited).
This can be avoided by disconnecting the hair from the mesh, but this will remove child particles.
Is there a way to keep hair (including child particles) in the same state while editing the mesh?

You could use a second mesh for the hair. This hair only object would sit just under the main object with the hair coming up through it.
This would allow you to alter the main object in any way you want without affecting the hair emitter.

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


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Why is my Cycles Smoke is disappearing in render?
I've made a smoke+explosion simulation and everything works just fine in viewport. But I have two issues that you can check in the blendfile below:
The first one is that some of my smoke is not rendering at all. The next images have the same scale.

As you can see, there is a smoke plume missing in render. It's weird because they came from the same emitter object.
The second issue is that the smoke disappear when the simulation goes further as if the flow object was emitting no more. Again the images have the same scale and placement.

It looks that the problem is not in the material but in the density of the smoke. This is an image of the Density Factor output and the problem is there yet:

I looked at your blend, it's very strange... the only thing I can think of is that it has something to do with your material, but I'm not very experienced with groups and couldn't figure out how to find it. My suggestion is that you try an identical scene with the 'quick smoke' (in quick effects) preset material and see if it's any better, then you can edit that material to will (if it works).

Good point, but it doesn't work either. But now we now that the problem is not in the material at all. The density factor (from Attribute Node) gives the same result, so the problem is in the Smoke Density. I'm gonna edit my question to add this. Thanks!

You're welcome O.o Can't say I know much about the smoke density though... Good luck :)

The size of your smoke domain and distance from camera are quite large.  Fine you may need that.  I noticed when I scaled domain and adjusted camera to zoom in on smoke, the preview and render more closely. My test was for a domain approximately base 8 * 5 units.  I used [group] smoke density set to 8.  Part of that motivation was to decrease render time.  Certainly a smaller domain provides more detail given other settings the same.  I am wondering if smaller domain tend to look more like the preview.  [group] smoke density to 15 produced thicker smoke everywhere but did not preserve detail.

This is because the max steps + step size is limiting the maximum distance volume rays are allowed to travel to a distance smaller than the total width of your domain.
Your domain is over 350 meters wide in the shortest axis. With the current settings in Render settings > Volume Sampling, the ray can only travel 1024 steps at .1 meters (BU) per step. In other words, the ray can only travel 1024*.1 = 102.4 meters before it must give up.
There are a couple ways to fix this.
Increase the max number of steps
This will keep everything as it is, but allow the rays to travel farther. It will likely increase rendertime however.

Increase the step size
This will make rays jump farther between steps and significantly speed up rendering, but may make the volume appear less detailed.
1024*.5 = 512 meters/BU, which is quite sufficient to traverse the whole of your domain. Note that details smaller than the step size may be "jumped over" by volume rays as they step along, essentially rendering the volume like those details were never there.

Use Equiangular sampling
Depending on your exact situation, you might find it's faster/less noisy to use Equiangular sampling for your volume. You'll have to experiment and see what works best in your scene.

I was about to report it as a bug! I found a workaround though: make another scene with the domain scaled down, reading the same Cache and the camera zoomed and shifted to have the new domain in the same place of the screen.


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How to call vertex groups in Animation nodes [SOLVED]
I would orient some instances by vertex normals, but i'd like to control orientation by vertex groups, to give z negative values to some instances, like in the pictures.is it possible? i've tried with Vertex Group Input but it gives me unexpected results.

Solved by 3DSinghVFX, then i've added a Combine Vector to control also Guides parameter from Vertex Group Input.

You can achieve that effect by controlling the scale of the normals with the vertex weight.

First, instanced an object (Cone) on the vertex locations of the base object (Cube) using this node-tree:

Then, remap the weight (using Vertex Weight Input node) which is in range (0, 1) to (1, -1) using Map Range node with the Threshold (in Threshold node) = 0.5 i.e., vertices which have weight less than 0.5 will have normals with scale = 1 (+ve direction) and vertices which have weight equal or greater than 0.5 will have normals with scale = -1 (-ve direction).

You can very the Threshold as you like.
Blend File:

Thanks, great! you are the man :) , there are also some other ways to call a group of selected vertex to give them parameters? maybe i need to create a new question on StackExchange?

Vertex Group Node gives the weight of all the vertices or vertices specified by indices. For selected vertex: you first assign a weight to the selected vertices then later you can filter them using Vertex Group Node and Mask List node. If you want to know in more details then please create a new question.

Thanks, i posted a similar question linked, because i'm trying to orient instances in more complex meshes than a cube:https://blender.stackexchange.com/questions/158093/animation-nodes-instances-orientation-in-a-dodecahedron

Please accept the answer of this question if you satisfy. I'll try to answer that question.

Ok, i did not know 'till now that one has to accept the answers. Thanks, done!

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


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Blender 2.8 / Windows 10 / Python - import Module fails, pip install Module fails, pip install Wheel fails
I need to use the VTK module in a python script inside Blender.  It seems that there is no Python 3.7 version of VTK for Intel chips (and B2.8 comes with P3.7) and so I'm now trying to figure out if I need to downgrade blender, python, both, or if some other (better) solution exists.
Running Windows 10 (sadly...certainly not by choice)

PyPI has a package for Windows 64 Bit and Python 3.7 https://pypi.org/project/vtk/#files

Ah, yes, but how to install on an Intel based machine...

Through pip install? If your question was regarding amd64, it's called like that for historic reasons. It's the right package for 64 bit independent of the CPU manufacturer.

pip install --upgrade pip + pip install vtk = ERROR: Could not find a version that satisfies the requirement vtk (from versions: none) ERROR: No matching distribution found for vtk
Also,
python -m ensurepip + python -m install vtk1 results in the same.  I thought it might be an architecture problem but it seems to be something else...
Trying from wheel: python -m pip install 'wheellocal.whl'  = ERROR:  vtk-8.1.2-cp37-cp37m-win_amd64.whl is not a supported wheel on this platform.

I just tested this in a venv and it works fine. Please check that you're actually running Python 3.7. (python --version) and ensure that it's a 64 bit install of Python.

I am not sure what the problem was, but thank you for your help.  I think this was an admin / not using the right pip problem.  I've added the solution to answers.
Thanks again.

I'm not sure if the reinstall and admin rights are necessary for all cases but the following solved my problem:

Uninstall Blender and reinstall as Admin
In Blender Python shell run
import sys
sys.exec_prefix

Open Powershell as Admin
Go to directory listed by Blender Python shell
Ensure pip
.\bin\python.exe -m ensurepip

Install modules
.\Scripts\pip3.exe install vtk

Thanks to @rgj for troubleshooting and this blog for Blender/pip instructions

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


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How to animate object with clothes to prevent cropping
I have my dog model and jersey on it. Dog's mesh under the jersey is deleted. I have done rigging with rigify, and now intend to do the galloping animation. Problem is on the front legs, where the scalpula is and the jersey. What could be best way to prevent cropping. Additional rig for jersey, to put it around sleeve, and how to combine my custom rig and rigify?

Hi Radoon, small hint: don't ask "what's the best way..." because these type of questions will be closed due to "opioned based" question - that's a rule of this site.

from your third picture it looks like the body and the cloth don't seem to have the same weight?

@Chris yeah, thanks. however that's what first comes in mind since there is a lot of ways of solving problem :D gonna start using something like how to

@moonboots it does not, however when I try to paint all red it still pops out. Thought maybe about driver bones or something like that. Gonna upload just leg as .blend file so you can check if you can.

it may still pop out if another bone influence the cloth and not the body or vice versa, but have you tried to reparent With Automatic Weights?

I uploaded just leg since I am not allowed to share whole mesh, I hope it's enough

I tried automatic weighting but it doesn't catch the jersey. I could do it manually with painting, but it crops


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UV islands appear as small dots on map
When I unwrap one by one object in my scene, everything is ok.
However, when I select them all, and then unwrap, most of my objects appear just as tiny dots on map and take very little space. First asociation is that scale is not applied but it is. Everything is merged by distance so there should not be overlapping vertices.
When unwrapping as Angle Based it seems ok, when unwrapping Conformal it is weird.

I'm not sure what you mean, here is what your file show, it looks normal except there are some overlapping faces: https://zupimages.net/up/22/44/57rh.jpg

That's with angle based I think? I mean, I can wrap it as angle based, no problem, but I used to unwrap hard surface as conformal, and this is the first time I face this problem.
I uploaded screenshots of the problem in my question now.


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Keymap warnings when using the "Industry Compatible" keymap on Blender 4.0
I'm using the Industry Compatible keymap. When I open the console, it's getting flushed with this warning:
WARN (wm.keymap): C:\Users\blender\git\blender-v400\blender.git\source\blender\windowmanager\intern\wm_keymap.cc:492 WM_keymap_poll: empty keymap 'Grease Pencil'

These disappear when I'm using the Blender native keymap.
Is there a way to get rid of those without using the Blender native keymap? I'm using the console for scripting feedback and with these warnings it's pointless.

This might be something to tell the developers about. Please use the menu Help > Report A Bug and see what they say about it.

@clawjelly Have the same problem and as a scripter, this is a showstopper. But it's solvable: Go to Edit > Preferences > Keymap > Grease Pencil > Grease Pencil Global and click on + Add New. This should stop the warning spamming.

@L0Lock there is a solution with pure user interaction on Blenders preferences. It that still off-topic? Voted to re-open so i can answer.

I don't have rights to reopen topics, but it wouldn't change my mind otherwise: this question still appears to be about an issue caused by a bug that the devs should solve. You posted a workaround as a comment, that's totally fine as it is.

@L0Lock ok thx. I was about to give a little more extended answer and add some screenshots.

@taiyo An answer that solves the problem or can be used as a workaround is of course welcome, but the problem should be reported as a bug so that it can be fixed.

@quellenform thx for re-opening. Of course it should be reported, didn't want to imply anything else. As i faced the same problem with the warning spam and i found no answer online i was just inclined to create one.

The warning tells what's wrong, so when you navigate to Edit > Preferences > Keymap > Grease Pencil > Grease Pencil Global you will see that there are no keys mapped at all which causes the warning. Not sure though why this is the default setting and, as @L0Lock pointed out, should be reported (Help > Report a Bug). To remove the console spam, just add a key map item by pressing + Add New. This already should stop the warning.
If you are a Grease Pencil user you might be interested in some useful key mappings. A fresh Blender 3.6 install shows two default mappings which can be taken over to 4.0. Add two new key map items, paste the command gpencil.active_frames_delete_all in there and edit the key commands as seen in the screenshot (Backspace and Delete respectively).


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im working with the hair curve and trying to attach the curve to a new mesh
I created a hair curve on a mesh and im trying to add the curve to a new mesh. when trying to play with the curve and make it look better a node show an error:
Evaluated surface missing attribute: "rest_position".

I don't know how to resolve this issue.

Are there any other modifiers before this geometry nodes modifier (Including other geometry nodes) ? Or any shape keys?

no I checked, not unless they are hidden somewhere.

I was able to recreate your error by using shape keys. But I don't know about modifiers. viz why I asked if there were any other modifiers or shape keys

And yes I am talking about modifiers and shape keys on the face model

An easy way to get past that error is to simply add empty hair to the mesh. You can delete it right after. That clears up the rest position error.
Then you will get another error Curves are not attached to any UV map. Well they are if you set up the curves with the surface and UV map filled in.
Just select the curves and go to sculpt mode. Under Curves, select Snap to nearest surface.
That clears up the UV map error and you are done.
I put up a short video of all the steps at https://www.youtube.com/watch?v=svyoFbmv5VM


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How to make a material switching from Wire frame material to surface material?
Is it possible animating the wire frame material Changes to surface material?
I want to make a material that's first Wire & it fades to solid surface material & Vice versa.
Blender Internal Engine

Usually these types of animations are done by rendering 2 entirely separate animantions and crossfading them in video editor so that it can be adjusted and previewed more swiftly. But you could do it with materials that have something like X-position determining the material transparency.

@kheetor Can you add brief answer?

@kheetor don't put answers as comments

I don't know if there is a better way (I don't usually use Blender Internal) but this can be done with material nodes to generate the wireframe using the UV coordinates.
To generate the wireframe we can use the default unwrap (or use UV Unwrap->Reset to reset back to default) and have the material solid if U or V is less than 0.1 or greater than 0.9 (use values closer to 0.0/1.0 for thinner lines).
To get the wireframe to slide across the mesh we can split the coordinates into the respective components and use Math nodes to generate a cutoff, keyframing the value to animate the transition. Note that I've used the X coordinate (split from the vector using the Separate RGB node (RGB translates to XYZ), combined with a fraction of Z so as to make the transition plane not coincide with the sides of the cube (or you get an ugly transition as the whole face jumps between being transparent and not transparent).

Ensure to enable Transparency in the Render Pipeline Options of the material to allow transparent materials.
This produces the following result :

Would it work on complex materials?

Yes - it should be fine with more complicated materials since it’s only controlling the alpha - the material itself should be independent - just replace the Material node with your own. The only real requirement is the UV used to produce the wireframe - if you have a more complicated unwrap or non-quad faces then you’ll need another way to identify the edges (Cycles has a Wireframe node but I don’t think BI has an equivalent).

Here's for the crazy ones:

From Haunt's trick bag:
I have two pencils and a huge cube. I animate the cube so one side of it serves as the transition border.
Both pencils have a Boolean Modifier using the Cube. It's just that one pencil keeps what sticks out and the other keeps what's inside the cube.
The boolean modifier has the cool feature that it will use the first material slot for the new faces. Which means for the pencil sticking out, you need to create a transparent material for the first slot and assign the other three slots to the faces.
For the pencil sticking inside the cube, it's irrelevant since it's a wire material. If you need the transition plane completely wire free, you'll probably need two cubes with both booleans set to difference.

Did I mentione that there's yet another way? No?
Well, there's yet another way!

The trick is kind of the same. You have one pencil with the wire material and one with all the rest.
All materials share the same blend texture with cranked up contrast to narrow the transition zone a bit. This texture controls the alpha channel. -1 for the wire, 1 for all the ordinary materials.
The materials need Z-Transparency enabled and alpha at 0.0
And the trick is that the blend texture gets object coordinates. That way, you can animate an empty and decide where the border should be.

That pencil again? I'm getting tired of it.

@ScottMilner I can do pencils all day. Embrace your inner pencil. The more you complain and nag, the more my pencil powers activate.


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Why is png image in video fade out pixelated?
I have used a png image in a video and added a fade out in VSE using the Gamma Cross. I just have another audio layer in the video. See attached images. I am using Blender-Render engine.

I am attaching three images sequentially fading out. You will notice that towards the fade out end the image starts to pixelate. Why does that happen?
See image state while fading out:

The image has been created in Gimp with following

Even on a 200% zoom it does not pixelate.
What should I be doing to avoid the same?
Blend File as requested:

I can seem to download the blend file. see

Could you possibly post the blend file?

@Ben Sure. But don't know how I can upload a file. Do you mean like a Link?

https://blender.meta.stackexchange.com/questions/658/including-a-blend-file

@Ben apologies for the delay. Kindly find the blend file added to the post. Awaiting insights. Thanks

I hate to break it to you, but it doesn't seem like the link works.

@Ben Thats strange, I am being able to download the file. See added screenshot.

@anand Didn't work for me either yesterday, I can open it but the file is almost empty as if you are using paths in your .blend that go into your local directories and aren't included

@WhatAMesh Same for me, just downloaded it.

@anand Could you re-upload your .blend file but this time before uploading go to File>External Data> and click Pack All Into .blend

@Ben So I have packed the .blend file, couple of times as suggested. Then I got the the msg - "No new files to be packed" . So I am assuming that all's well. Folly of a newbie, kindly bear.

The "Lossless" setting is a variable bitrate value. When the image looses information during a fade to black the bit rate drops. Change the Output quality to "Constant Bitrate". Place a high value, that retains the quality that you want.

Thank you so much for the resolution. My apologies for the delay in replying. I have uploaded a new blend file - . But the png image is not exported in the film. I am not sure incase its due to the lossless setting. Kindly suggest


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What is this anomaly when I'm trying to sculpt and how do I fix it?

The mesh derived from a cylinder and I've put Mirror, Bevel and Subsurf modifiers on it before sculpting.
EDIT: Ok, so flood filling seemed to have fixed the weird stretching. But the brushes don't work on the top side of the mesh.. I can sculpt the sides just fine. Note: I've scaled the mesh down on the Z axis but I've applied the scaling.
Here's the project(excuse the messiness, I've been experimenting a bit on that project):

Either poor topology, uneven mesh density or https://blender.stackexchange.com/questions/80840/why-am-i-getting-a-jagged-brush-when-sculpting-with-dynotopo/

@DuarteFarrajotaRamos I've been scaling it down on the Z axis a bit, but I've applied the scale. I've also tried flood filling it, but the weirdest thing is: I can't seem to sculpt on the top of the mesh. Sides are working just fine, but the brushes don't work on the top...

Provide us the .blend here mate. At 1st try to Remove Doubles and check if You dont have faces inside.

Have you made sure to apply all the modifiers? I get similar anomalies when not applying my subdivision.

yep, applied them all

Problem Breakdown
As Duarte already assumed, your mesh has uneven density. This is a problem for all sculpting methods, since the algorithms get confused about which edges to subdivide.
However, there is a possibility to fix this by using Dynamic Topology and relative detail.
You also want to use a "sharp brush" Texture in form of a simple white png with a black outline (image below).

Fixing the Topology and smoothing the Surface
In Sculpt mode, activate Dyntopo, switch from "Constant Detail" to "Relative Detail", change the Detail Value to 4.0 and activate "Smooth Shading".
While you are here, also deactivate all settings in the Symetry/Lock section below (image below).

Then, select the "Clay Strips" Brush, lower its strenght to 0.1 and lock it to "Area Plane".
Under "Texture", add a new texture, load the "sharp brush" texture from above and activate "rake" and "random" (image below).

The setup is now complete and you can start fixing the topology. Sculpt only with a small portion on the handle and the pommel.
When switching to Edit Mode, your topology should look more or less like this:

Back in Sculpt Mode, switch from "Relative Detail" to "Constant Detail", change the Resolution by using the "Sample" button to sample it from the newly sculpted portion of the mesh.
Next, hit "Detail Flood Fill" and then "Optimize" (image below).

Switch back from "Constant Detail" to "Relative Detail", change the Detail to 8.00, then select the "Smooth Brush" and select the "sharp brush" texture from above.
Turn on Matcap and select preferably a glossy one to highlight distortions.
Turn on "Rake" and "Random", then start smoothing the whole mesh. Be careful around the sharp edges, turn down the brush strenght to 0.2, if necessary.
Work your way around the mesh until everything looks smooth (image below).

Your mesh shold now be fixed and you can start to add the details. You might want to play with the Detail settings under Dynamic Topology to get the detail level you want to see in your result.

First of all, thank you for your time! Second, I've done everything step by step but when I got to the smoothing part, it didn't exactly smooth.. Quite the opposite, it made the surface rough and I still had the problem of brushes not working correctly on the top. When I use the snake hook brush, the result just slopes to the sides, it doesn't go to the Z axis at all. Here's the file: https://drive.google.com/open?id=1H0TsTu_10QnxaBQD8ITPxsZEbxKyheIS


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How do I make weight painting not a living torment?
So I got a pretty high res mesh that I've managed to get down to around 600k verts. But I still have extreme low performance in weight paint mode in the viewport which makes it so much harder to work. I get like a 3 second delay after each stroke and it doesn't help that this is my first time rigging a character and I have barely any idea if I'm doing it correctly. Any tips or is this just the sad reality?
EDIT: here's a screenshot:

600k is just too much. You will have to do a (manual) retopology preserving the high details only through maps. Giving us a screenshot of your model could also help.

@Leander i used instant meshes for quick retopo and  then a multires with shrinkwrap to preserve the details for later. how exactly would i go on with the way you said?

Your mesh (before the multires) has to many vertices, try getting to 10k-40k. There are plenty of tutorials on how to do a retopo on a highres model.

@Leander manual retopo seemed too tedious to me and i wanted to do a shortcut. i'll try it in the future, but so far, i think i can manage. at least i can rest easy knowing that there's an easier way, thanks

"manual retopo seemed too tedious" and "knowing that there's an easier way" doesn't seem to match. Yes, topology is hard, but there's a reason for it. Good Luck!

if you plan to animate a very high poly mesh it's going to be horrible... as Leander said you should retopologize your object, then bake the high-poly to keep all the 3D details on the low-poly with a normal map, it will be a huge relief

Retopologize your mesh. Once you´re done, then you can assign weights using armature.
Also: Select your mesh, use the modifier: DECIMATE: Choose 50%. Check if your model is ok for you in shape. If it is and you´ve reduced the polycount to half, please reconsider retopologize. Basically you can´t work with an armature on a very dense mesh.
Thank you for your consideration to vote me as the answer by clicking to the left :the icon with a check mark and upvote this answer.
BFCT_Schiller


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How can I prevent force fields from affecting hair or other particles?
I want the turbulence force field to only affect my smoke sim, but it's also messing up my hair particles. I've tried setting Effector Collection to the collection the smoke simulation is in (the hair is in a different one).
EDIT: project file - https://drive.google.com/open?id=1O7bqU8FNCZyATB6S46CRcYuGLIb2OSEb

Can you include the blend file too

@covector sure, i'll add it

I set the effector collection to the collection the hair emitter is in and the hair stopped moving. You should set it to the collection that the hair is in instead of the collection the smoke is in.

ooooh so i need to set the hair field weights to it's collection. i thought only the emmiter would be affected if i set it's own field weights to it's own collection. cheers!


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Subsurf Modifier artifacts
So I was messing with Subsurf modifier to create a certain sword and then some weird artifacts began to appear (cape-like). I've tried adjusting the Crease, but couldn't achive what I wanted. Basicly, what I whant is the as on the screens, but wo any artifacts :)

Also, here's the .blend file, cause I assume I didn't make myselt 100% clear.
https://drive.google.com/file/d/0B0hdCv37NrtVMXU4eFB2MFFlMGM/edit?usp=sharing

You have some non-manifold geometry in your mesh.

There is a large ngon overlapping the other polygons.

Here is how to fix it:

Select the large ngons

you can either do this manually which is faster in this case since there are only 2 ngons or you could use a selection tool.
Select -> Select Faces by sides: greater than 4

Delete them: x -> Faces (3)
Select all geometry in the mesh: A
now to fix the holes: Mesh -> Clean Up -> Fill Holes

This fixes part of your problem. The other problem is the creasing. To fix this I would either use edge loops instead of creases or crease all continuous parts of the mesh rather than just single edges.

yeah, I should've found those ngons myself, thanx for the answer :) didn't quite solve the problem with the capes above, but I think I'll just mess with the topology (because creases also didn't have any affect)


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Weird light around my meshes in Cycles rendering

What could be source of this weird orange light around cookies and what could be fix?
I am using Cycles render and CPU(I have old GPU which is not supported in Blender 2.9 anymore).
I am talking about orange light between cookies, where my mouse cursor is on the 2nd image.
I accidentally applied subdivision surface modifier so those cookies have a lot vertices, but there are no other modifiers active.
I am using 3 lights, 2 area and point, but even if I disable them, this orange color can still be seen. Lights are white.
For plate I am using Porcelain from BlenderKit addon, but even if I disable plate that orange color is still there.

Please [edit] your question. It would help if we knew more about the scene. Start by showing us the material you are using for the cookies.

More info to add: what kind of lights are you using? What is the world background? Are you using a GPU for rendering (by default you would not be)? If so, what make and model? What are the material setups for the plate and the cookies? Are you using a third party image texture or a procedural texture? What coordinates are you using for that texture? Are there any modifiers on the cookies?

Can you circle exactly what you are talking about?

Umm, there's no mouse cursor in the second image. I think it is disabled in the screenshot program :-D

I'm guessing you are using a texture to make the cookies look dusty with faked normals or bump-mapping (not bad, BTW), and are mapping whatever texture via UV coordinates. I also assume that the orange light you are talking about is the bright orange ridging on the edges of some cookies.
The fact that this is at a corner and seems to be in a straight line makes me think this is a texture mapping problem, and that the normal changing is not happening there, which leaves those parts of the cookies appearing perfectly smooth, and thus brighter.
Check that those edges of the cookies are properly UV mapped and not scrunched into some corner, and if you are using an image texture, check that the image node's mapping setting is set to "repeat" and not "clip."
Separately, one cookie that is sitting flat is penetrating the plate, thus making it look unnaturally bright, because in real life light gets trapped between the edge of the cookie and the plate, making it dark. This is called "Ambient Occlusion," and can be faked in EEVEE, though Cycles should do it by itself.
To help you position the cookie correctly, use Wireframe view and then go into orthographic from the side.

Thanks for detailed explanation. I am having problem with stacking cookies, somehow when I change anything there is overlapping somewhere, is there any more precise(automatic) way?
About UV mapping, it is mess. A lot of overlapping and since SubModifier is applied there is lot of face triangles and it is hard to clean them up. Can I somehow automatic sort them so they are not overlapping?
I edited question, sorry for the unclear information.

The stacking is another question, but in short I recommend using the physics engine. I also recommend reading the whole manual from beginning to I-don't-need-this-anymore phase (as opposed to I-am-bored-to-literal-tears phase, which I hit around modifiers but now I love 'em).

UV mapping is also another question. The short version is that your job in UV mapping is basically to mark seams. If you were trying to wrap the cookie without being able to fold anything, but you had slightly stretchy fabric that could stick together at the edges, how would you do it? Mark seams along the edges, then "select all," and "unwrap."

Edit: Looking further at the material node setup, I would say the mesh is not manifold or has normals oriented backwards. Maybe add close-ups of the suspect areas in edit mode?

Hahaha ok thanks for the tip for manual :D
I will post screenshot of the cookie in edit mode, you will see faces are very messy on the part where the lighting is problem. I think it is because of that. Probably better to start cookie from beginning since it is easier to make it again than correcting all those problems


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Texture painting my model from 2D .jpeg picture or better solution

How to realistically paint horse model? Is best option texture paint from image, and how to do it for the mane and the tail

Is this the tutorial you watched? I know it is an older version, but the tools are about the same function since nothing has changed in Texture Paint tools yet. https://www.youtube.com/watch?v=p4ngVoGIj1Q

Hello. I watched a lot of them, also watched this but got me confused so I asked for help. But maybe I just need more practice and experience with texture paint. Thanks!

Your post has several questions in it but needs to be a specific question we can answer. If you can edit it down to a specific question, we can try to illustrate here how we approach it, and you can ask a new question post for any other specific point you have trouble with. I try to monitor the paint questions and answer best I can, but vague questions are impossible.

Ok sorry then. Now I fixed I hope it is clearer. Thanks


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How to get same Render as in Viewport (Eevee)
There is similiar questions but I couldn't manage to get good answer.
1st Viewport screenshot
2nd Render in Eevee
They're both transparent don't mind that.

Tried tweaking World node as seen in one answer but couldn't get it right. Can't get inside of wheel, and especially balls, to look same.
In viewport shading Scene lights are on, Scene world is off with studiolighting

hello please share the file

I did, don't mind broken animation. Thanks!

You need to reactivate your Scene World option in the Viewport Shading panel, otherwise it will be the Material Preview world that will been taken into account:

Thanks, tried that, but then my viewport is same as render. But I want my render to be like viewport. As seen on my first screenshot in my question.

In that case you need to use the same HDRI used in Material Preview, check this answer: https://blender.stackexchange.com/questions/158336/using-material-preview-hdri-in-renders#:~:text=In%20Blender%202.81%20you%20can,settings%20from%20the%20World%20tab.

Thank you. Now I see

Or, do a viewport render.


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How to make an object follow a Rigid Body as if the object is parented to it in animation
I am making an animation of a box opening. I have a lock which I want to unlock and throw in the air, that is animated. So I added the Rigid Body physics to the lock to make it fall realistically to the ground.
However, that lock is made of 2 separate objects, so they can be animated separately. Then after that, I would like to have them fall down as if they were joined - one rigid object. However, I can't have both so I need a way around it. I've tried parenting, but it's not possible. It seems some of the object constraints would work best, but can't find the right one.

Are both objects animated or only one?

Check my solution, should work, as I've tested it on a lock myself.

In case one object is animated:
Select your animated object, and go to object constraints>Child Of>Select your other object. Now when your animation is finished, or at the frame you want the rigid body to start, go to scene properties>rigid body world>cache>set that as the start frame. Now your inanimated object will drop and the other one will follow it.
In case both objects are animated:
Go to the child of constraint, set it to zero, and press 'I' on the influence value to keyframe it. Now go to one frame before the frame in which you want your lock to start dropping (which of course is the frame In which your keyframe animation is finished), and press I to keyframe again. On the very next frame, set the influence to 1 and press 'I' to keyframe. When your animation is finished, or at the frame you want the rigid body to start, go to scene properties>rigid body world>cache>set that as the start frame. Now make sure the other object has a rigid body, and you're good to go.

It works, but problem is, it's very dizzy, it's rotating and shaking. Is it about rigid body settings or

@Radoon It must be fixed by tweaking a few settings, I could test and try if it gets better if you can share your .blend file.

I added blend file with just lock. Hope it's okay, because it's project work and didn't want to make whole scene available

Yes, that's fine @Radoon. Will update in a few minutes.


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How to change material's color in blender game engine?
I am making a new racing game in BGE. I want my game to have a feature to change car color in-game (car consists of multiple materials, but currently I want to change body material). How do I make something like this:

Without text (only color select) in blender, so it can apply on material in other scene?

First you have to enable Object Color, that is found in the Properties window, Material tab, then under the Options region Object Color.
One quirk I found, be sure that the diffuse color of the material is pure white [1, 1, 1]. If it is not you will only be able to control the color up to that level. Example: say the material's color is red [1, 0, 0], now because the green and blue channels are 0 you will never be able to get any value in those channels.
Now the material will use the object's color, that color is found  under Properties > Object > Display > Object Color*.
To change the object color while the game is running use this bit of python.
cont = bge.logic.getCurrentController()
obj = cont.owner
# set the game object's color
obj.color = [ 0.0, 0.0, 0.0, 1.0]

The color method is looking for a vector in the form of [Red, Green, Blue, Alpha], (You can just leave the alpha set to 1, I have yet to find a place where it is used.)
The game UI for changing the color
Creating the interface is the most complicated part.
Here is a working  demo file with three sliders, one each for red green and blue.
The three sliders all have a game property one for each color channel. They also have these logic bricks. The only difference among the three is the property name.

This script is what takes the input from the logic bricks above, and changes the three values.
scene = bge.logic.getCurrentScene()
cont = bge.logic.getCurrentController()
own = cont.owner

if cont.sensors['Mouse'].getButtonStatus(bge.events.LEFTMOUSE) == bge.logic.KX_INPUT_ACTIVE:
    posZ = cont.sensors['Mouse1'].hitPosition[2]
    if posZ > 1.0:
        posZ = 1
    elif posZ < 0:
        posZ = 0
    own.worldPosition.z = posZ

prop = cont.actuators["prop"]
prop.value = str(own.worldPosition.z)
cont.activate(prop)

Then another script on the object you want to change the color is this script. A always sensor set to True pulse mode makes the script run constantly.
scene = bge.logic.getCurrentScene()
cont = bge.logic.getCurrentController()
own = cont.owner

r = scene.objects['handle']['r']
g = scene.objects['handle.g']['g']
b = scene.objects['handle.b']['b']

own.color = [ r, g, b, 1.0]

If you are ok with having a few set colors, then there is a way to have color changing in the BGE with no python.
First duplicate your object that should have the different colors, move it to a different layer. Duplicate it once for each new color, and give each a new materiel. Change the color of each material (duh). Rename the Mesh data so you can keep track of which one has what color.
Now back on the real object, add one Message sensor, and one Edit Object actuator for each of the different colors you created for your object, like the logic bricks below. You should set the different colored mesh data (this is why you should of named them) in the Mesh field of the Edit Object actuator.

Finally create a menu like this to hold the buttons that will change the color. You will need a button for each color. Give each button logic bricks like in the image below. The subject in the Message actuator is important, that is how the button changes the color.

When you click on one of the buttons it send a message with the color. The message sensor in the object that will get its color changed, reads the color from the subject line, and triggers the correct Edit Object actuator.
Blend file

(Having come back to this question to fix dead links) I now have another method to change an objects color in game without python.
This method does not use duplicated object data, nor any python.
Start by animating the color of the material. I used 7 key frames placed at the major colors around the color wheel. Just choose the saturation and value, then use the hue slider to change the color. This way you get an animation all around the color wheel ,see gif below.
Please pardon the terrible dithering in the gif...

With that animated now on to the logic bricks.  I will skip the game buttons because they are exactly the same as the buttons I made in this answer
First we need a game property. I called mine "frame," whatever its name make it an integer.
Now the magic happens in the logic bricks behind the main object.

Start off with an Always sensor, with true level triggering enabled. Plug that into an Action actuator. This action actuator is what controls the animation we made earlier.
Be sure to set the Action Playback Type to Property.
Set the Property field to the one created earlier (I used "frame").
Last set the Action name to the animation we made first. If you did not rename it, it will be named "Your_Material_NameAction".

At this point you can change the color of the material by changing the value of the game property.

All that is left to do is, tie the message that each of the buttons send to a value. Example from my animation (as can be seen in the gif) I have red at frame 0, blue as 64, yellow is 13 etcetera.
To do that add a Message sensor, the subject is from one of the buttons, made earlier. To be logical (remember we are using logic bricks) I named the subject of the message my yellow button sends "yellow." Hence the message sensor listens for "yellow."
Plug that into a Property actuator.
Set the Mode to Assign, the Property to the game property made earlier (remember I called mine "frame") and the Value to the frame that corresponds to a yellow color.

Repeat for each color you want, and your done.
The full blend

authors: Виталий Билоус


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Things are red when using blender 4.2 EEVEE next
On blender 4.2 I'm having this problem where all my objects are turning red when I use EEVEE. I can't figure out how to make them a normal color. I've tried changing the texture, changing the rendering settings. I don't know what to do.
Viewport, There are no nodes hooked up but its still red:

Rendered result (EEVEE):

Rendered result (Cycles):

Hello and welcome. Instead of having users go through links and external sites please use the builtin tools to embed images in your post. See How to upload an image to a post? or GIF

Does this also happen when you create a new file and directly render the Default Cube?

The problem is in the IOR, you must change it to 0  like this

Normally by default it is like this

Make sure you do not have multiple Material Output nodes in your shader. By default, the Material Output is set to All, however there is also the option to set it to EEVEE or Cycles:

This is helpful when you specifically want different material outputs for different render engines in a single material, to not have to switch materials when switching engines, maybe because some setting which looks good for EEVEE does not look good in Cycles and vice versa. Some shader nodes do not work in both render engines but maybe you still want to use them in case you render with the engine that can use them.
Now the three options work with this logic:

If there are specific outputs for each engine, one for EEVEE, one for Cycles and none for All, of course the output according to the engine will be used.

If there is a specific material output for e.g. EEVEE, this will be used for EEVEE, an additional one for All will be ignored and used for the other engine.

If there are three different outputs, one for EEVEE, one for Cycles and a general one for All, the general one will be completely ignored and never used.

If there are two or more outputs for the same render engine, the one that is (or was last) active is the one that is used.

If the engine is EEVEE and there are two or more e.g. outputs for EEVEE, but the active one is for Cycles or All, then the "oldest" EEVEE output will be used.

Well, images say more than 1000 words. Here are some examples. First we have a red material for EEVEE, a green one for Cycles and a blue one for All.
Not surprising, when the engine is set to EEVEE, the red material shows, set to Cycles the green material shows and the blue one does not appear at all.

But if I now get rid of the green Cycles material while the engine is set to Cycles, then the blue material for All will be used:

Back to three outputs. This time, we have the green material for Cycles, but two materials for EEVEE: red and blue. If the output of the red material is active (indicated by the bordeaux-colored label while the others are grey), the object shows red. If the blue material output is active, the object shows blue.

And now this happens when the render engine is set to EEVEE, but the active material output is the green one for Cycles: Of course EEVEE will not show the Cycles material. But it also does not keep track of which EEVEE material was active before. Instead it falls back to the EEVEE output node which is "oldest" in the nodetree. In this case the red one:

The output which is used is not determined by some alphabetical order according to how it is named or in order from left to right how they are placed in the nodetree or anything but purely on the chronology in which the nodes were added.


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Where do I have to put the Bump on my nodes?
I made a material, added a bump before but it didn't worked at all.
where do I need to put the 'Bump' option on my nodes? Which is the correct place? I'm pretty new about using this.
Please help me!

Node Bump in "Vector" category.

Add > Vector > Bump. Connect like this:

You can also feed the texture directly into the displacement input of Material Output node and use Multiply Math node to adjust the strength.


text:
Cycles rendering objects all black
I added a texture to the bowl, and it came out rendered black. I unwrapped it, and I did a little node editing, to make the plane glossy and B&W. It looks fine in the preview, as well as in material view, and in rendered view, but not in the render.
Another weird part is that Suzanne is also black in the render, even though she just has the default light gray material and no node editing at all. If I render without the bowl, it's just Suzanne in black. I have no idea why this is happening.
Here's my bowl's nodes:

And here's rendered view

And here's the render

There's definitely a light in the scene.

Can you post the blend?

Was it working before you tried to apply the texture to the bowl? You'll have to update your post with  a .blend file.

@TARDISMaker I never rendered it before I applied the texture so I have no idea lol. And yeah, I'll upload a .blend

I found the issue, I'll have an answer up in just a few minutes

Me too, Render Layer mask layer...

@ToddMcIntosh Yeah, just finished writing an answer on it. Will we be competing to see who comes up with the better answer than? :)

No, no, no competition, you post your answer.

I think what happened here was just a misclick in your render layer settings. It looks like you accidentally added a layer as a mask layer.
What is a mask layer
A mask layer is a layer that is used as a mask to turn parts of a renderlayer transparent depending on if anything (that appears in the render) is infront of something from that renderlayer.
What's the issue?
Your issue, is that you have your first layer (the one that has all your objects on it), set to be a mask layer, so essentially what is happening, is that instead of rendering the objects, there shape is filled with transparency. I just doesn't appear transparent because you don't have film transparent checked.
To fix this, simply uncheck that layer from the mask layers.

I had a similar problem, but the issue was that the Material field in RenderLayer had a material in it, pressing the x on it cleared it and there after renders worked.


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Remove ridges from hemisphere in half circle ngon that appear with the Subdivision surface modifier
I am in the process of modeling the front of a helicopter and I am having some difficulty in getting the nose of the model to behave the way I'd like it to when applying the Subdivision surface modifier. I have found this post regarding the issue, however the solutions do not work as I have only modeled one half of the helicopter and I am using the Mirror modifier to duplicate the mesh across the X axis. The ngon that is the nose is not a circle but rather a half circle. If I create an additional edge loop and move it closer to the center, the issue is still present and makes the tip of the nose into a point after enabling the subdivision surface modifier.
Here is the model in edit mode without the subdivision surface modifier:

And here is the model with the subdivision surface modifier enabled (problen circled in red):

If I enable "Adjust cage edit to modifier result", you can see that the first edge loop is in a very shallow v pattern:

If I add in a second edge loop that is closer to the center as suggested in the post linked above, the ridged mesh topography is still present, it's just confined to a smaller area and is more pronounced the higher the Subdivision surface level is raised:

By shading the faces smooth rather that flat, the ridges are no longer visible, however, I do not wish to use smooth shading as it does not fit the scene stylistically (think like the game SUPERHOT). Is it possible to remove the ridges that the Subdivision surface modifier creates without applying the Mirror modifier and manually adjusting the mesh topography?
UPDATE:
Because the shape is not a true half circle, but rather a half elipse, when attempting to convert the single center vertex to edge loop vertices on the same coordinate, they do not scale properly, Here is the result of performing the suggested answer from Shady Puck (with the "Adjust cage edit to modifier result" turned on in edit mode for clarity):

See http://blender.stackexchange.com/questions/6425/keep-sharp-edges-when-using-subdivision-surface. This is because of triangle fan in the nose of the model. It's better to remodel it..

Have you tried applying the Subdivision Surface Modifier after the Mirror Modifier?

@MrZak, can you elaborate how to remodel it? as the question stated, I've already tried to add additional edge loops and having a single ngon looks terrible

@RickRiggs, the Subdivision surface is after mirror modifier.

Some ideas posted here btw - http://blender.stackexchange.com/questions/3199/weird-deformation-between-large-ngon-and-edge-ring. In general, you can leave ngon only if there's a flat surface (aka one around nose) and surround it with quads.

You just need to remove the single vertex, then extrude the inner rings until you can fill the final loop with an ngon. If it's small enough, the ngon should look okay.

Start:

End:

Instead of having the center point be a single vertex, have it be a half loop cut of vertices all at the same (X, Y, Z) Coordinate.
Here's how you can do this.

Select the center vertex.
Key Shift + S to open the snap menu and choose Cursor to Selected.
Key . to set the Pivot Center to 3D Cursor.
Key X to open the delete menu and select Vertices.
Key Alt +  RMB to select the nearest edge loop.
Key E, then S, then 0, then Enter.
Key Ctrl + R to position a loop cut in between the center vertices and the next edge loop.  LMB and then immediately  RMB.
Key T to toggle open the Toolshelf. Under Loop Cut and Slide, set the Factor: value to -0.995.

The procedure:

I just tried this and it works and it doesn't work.  the starting shape is not a true half circle, but rather a half oval. I really wish I could put a picture in the comment to show you.

@вʀaᴎᴅᴏƞвєнᴎєƞ You could edit your question and add another picture.

Question has been updated.

@вʀaᴎᴅᴏƞвєнᴎєƞ Ok, I'd say either lessen the Factor: to .99 or low enough until it looks right or upload a .blend file to Blend Exchange and I'll look at it.

This artifact is a consequence of how the SubSurf Modifier subdivides triangles.
The best solution is to add an edge loop like you did in the last image, but before committing your change, slide the edge loop very very close to the point.
Alternately, you could use the knife tool to cut an edge very close to the point.
Either way, your objective should be to turn those triangles into quads so that SubSurf has a better chance of smoothing them the right direction.
The BEST solution would be to NOT use a SubSurf Modifier. SubSurf is really not suited to the low-poly style because it likes to be smooth and curvy, not angular and simple. Just make the geo you need, and make it look the way you want.
Don't try to draw a straight line with a compass, just use a ruler ;-)

authors: вʀaᴎᴅᴏƞ вєнᴎєƞ


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How to slice a 3D object into multiple 2D images?
I have a 3D object (Rubik's cube) shown below:

I would like to slice it into many 2D images, for example 20 pieces, then save all the 2D images individually for image post-processing. But I am very new to Blender, I tried to look into Boolean and Array Modifier, but it only copies the 3D object and generates the same one, is there any suggestions to slice a 3D object?

When you say slice the object, do you mean something like viewing cross-sections of it? Like an MRI scan?

If you want something like @TheKalaakaar assumes, have a look at the Bisect operator. Go to edit mode, select all faces and adjust the operation. You can for example discard one side of the cut and fill the cross-sections.

Thank you guys for the information! Actually, I would like to mimic what they did to slice the 3D object and be able to save each slice (2D image) https://blender.stackexchange.com/questions/58153/create-cross-sections-and-2d-planes-in-blender                   https://blender.stackexchange.com/questions/207385/volumetric-slicing-in-blender

Do you want to have an image sequence where the slices show the shape/silhouette of the object or really rendered with all materials as if it was sliced to pieces?


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Geometry Nodes : get a differet random value for each mesh after subdivide
I'm on Blender 3.6. I've made a geometry node to build a building from a plane, I want to build one to build a block, I subdivide a bigger plane and apply my geometry node for building (BatMain on the picture). It works (i've my buildigs) but i can't randomize the number of floors. I try everything but nothing works.

I've ever try to replace Value by Position or ID.

how shall we help you? we have no idea what your node group does...

There are quite a few ways of achieving  this.. which one would depend on your existing method. As @Chris says, for an answer that suits you, you would have to show us how you've got as far as you have. A plain-language description of your strategy, and a shared .blend on https://blend-exchange.com/ would really help folks to help you.

My file is to big for blend exchange....

I don't know how to explain in a better way (excuse my english)...

I have a geometry node (call BatMain), who, applied on a plane.... build a building with a number of floor dependending  on a parameter (NbFloor on the picture)...its work fine.
I try to build a "Block" (neighborhood?)  node for create many buildings of different height (floor numbers) on a plane.
I subdivide the plane (by 2, so ti's make 16 plane) ...
i apply my BatMain node (for bulding)... it's work, it's create my 16 buildings (image2)
i want to randomize the height (NbFloors)....  I cant....

Someone said me on another forum thats because the random value output is a square and the NbFloors Value input is circle, either the both are integer it cant work....


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Clear folder before rendering, automatically
Is there way to remove previous render files from output folder automatically before rendering?
nvm. figured it out
import bpy
import os

# Define the path to the folder you want to clear
folder_path = "path"

def clear_folder(folder_path):
    for file_name in os.listdir(folder_path):
        file_path = os.path.join(folder_path, file_name)
        try:
            if os.path.isfile(file_path):
                os.remove(file_path)
        except Exception as e:
            print(f"Error: {e}")

# Register a function to run when rendering starts
def render_init_handler(scene):
    clear_folder(folder_path)

# Register the render initialization handler
bpy.app.handlers.render_init.append(render_init_handler)

You are welcome to write your script solution as an answer in the section below. You can also accept it. This way, other users who have the same problem can easily see that there is a solution.


text:
Symmetry axis is off center when joining
I am new to blender and still learning to navigate the interface. I am working on this model and my axis went off center after I joined the parts of the model. Now I can not work on the model symmetrically. Please help where you can. Thank you.

You joined two objects using ctrl+J right? Can you add some image too plz?

In Object mode right click >Origin to Geometry? If the origin's orientation is bad you can fix it as well

The order of selection matters. The origin of the object after joining depends upon which object you had selected at the very last.
I will show you by an example:
Here I selected Cube1 first and then Cube2. After that I joined then with Ctrl+J

As you can see, the origin of this joined object is the same as he origin of Cube2
Now I selected Cube2 first and in the end I selected Cube1. After joining:

The origin is now the same as Cube1
This applies to multiple objects as well.

Basically, the last object which you selected matters.

Technically true, but the core issue is the origin. Treat the disease, not the symptoms.

@L0Lock I don't understand what you are saying. Most probably he joined the objects in the wrong order which is why the axis is now off center. If he just seperates the and rejoins them in the correct way, the porblem will be solved, right?

"If he just seperates the and rejoins them in the correct way, the porblem will be solved, right?" No because separating meshes into new objects will give them all the same origin as the object you separated them from. Unless the user have a save from before joining, the only thing to do is to replace the origin, I.E. as @moonboots mentioned in the question's comments.


text:
Search an import way for implicit equation in blender?
I have a question related to implicit equation in Blender.
I made a project developing about 100 parametric equitation/ or algebraic minimal surfaces, first with xyz math function, later I translated most of them to Geometry Nodes.(example in the Attachment & screenshot).
Now I would like to make the next step and build a collection of the implicit equations like:
$ x^2+y^2+z^2+sin(4x)+sin(4y)+sin(4z)-1 = 0 $
But I don’t find a way, neither any kind of addon, nor a helpful article in this forum or in the www.
So, maybe one of you have an idea how to import implicit equations to blender?
I am happy about all hints and inspiring idea’s ✌

What does "implicit" mean in "implicit equations" exactly? For easy conversions, see How do i convert this equation into the node editor?

There are addons for creating nodes from equations https://blendermarket.com/products/node-expressions?ref=165

Hi Markus, “ An implicit equation is an equation which relates the variables involved”, so y= … or z=… it includes the relation. Like you see in the example 0= ….

Hi Tayio, the problem is not the translation  of equitations to proper Nodes, I made this many times. My question is how to integrate „implicit equation“ properly into Geometry Nodes?

As you say, it's a relation. So you take all but one variable as an input, and read the output as the remaining value. For example for $y = 2x$ (or $y - 2x = 0$) create a mesh line going from $x=0$ to $x=10$ for example, and then use the Set Position node to set the points' $y$ coordinate based on existing $x$ coordinate.

As far as I know, GN does not support implicit functions. You have to do it via python by plotting a series of points using specialized libraries like matplotlib.pyplot https://stackoverflow.com/questions/2484527/is-it-possible-to-plot-implicit-equations

@MarkusvonBroady implicit means an equation where you cannot separate the variables like y^2 + xy = 0, there is no way to define one variable in terms of the other, that is explicitly isolating one variable. So you need some other numerical methods to accomplish this and GN cannot do it.

@harrymckenzie thanks for your answer. Of course I was reading the post before, but I am bad in Python, and I have about 50-60 equation which I want to realize, so I thought that somebody maybe found another solution or a „helper-script “ to make it more easier

@smice so Markus has proven me wrong! there indeed is a way with Volume Cube node!

Here's one way to display:
$$ x^2+y^2+z^2+sin(4x)+sin(4y)+sin(4z)-1 = 0 $$

For a better visual Effect, with a strong PC you can Smooth (modifier) it out decently:

You can add a material connecting Texture Coordinate: Generated to Base Color:

+1 that's an interesting approach! i didn't know you could plot implicit functions! i double checked and this is correct. https://snipboard.io/vROzVm.jpg. In the other 3d equation stuff we used Grid and set position.

@HarryMcKenzie thanks for checking, because I didn't, and with those Vector Maths optimizations I was worried I could maybe get it wrong

this volume cube node is so cool. like holy cow.. finally we can plot any type of equation! really exciting! can i add another +1 vote??? on a side note though, this seems like a workaround? is the topology it generates clean? because you mentioned we need strong pc specs to smooth it out? sorry i didn't try it.

@HarryMcKenzie the topology isn't any good, it's remesh. In general plotting is just sampling in a grid, though it can be postprocessed and smoothed out in various ways…

Hi @MarkusvonBroady, that i really interesting!! A big thanks for this. I will tryout later how far I come with this. Many thanks for your help …( I tried it with „points to volume“ and volume to mesh, but it was not nice.)

Hi again @MarkusvonBroady. Two question (if i may ) In the original Equitation it seems to be like the "negative" version of your result?  Screenhot 1 Could this be? And the second one is related to screenshot 2 - i guess we are using a different Blender Version - the result in case i try to reproduce it, looks different Screenhot 2 - Did it miss something ? (my ver. 3.6.0)

@smice This is because I rendered only in range $[-1, 1]$ on each axis, therefore the shell is cut and you can see the inside. You have an error here: https://i.imgur.com/pjBVfgP.png

@MarkusvonBroady - sorry for my fault - works perfect your way !  i love it - thx so much ! !

I know the original post was looking for a pure Geometry Nodes solution, but others may already have a point cloud or generated theirs using Python. In this example, we generate our point cloud by iterating over a set of values and using the OP's original equation to determine the positions of the points
$$ x^2+y^2+z^2+sin(4x)+sin(4y)+sin(4z)-1 = 0 $$
import bpy
import math as m
import bmesh

mesh = bpy.data.meshes.new("point-cloud-mesh")
obj = bpy.data.objects.new("point-cloud", mesh)

scene = bpy.context.scene
scene.collection.objects.link(obj)

bpy.context.view_layer.objects.active = obj
obj.select_set(True)

bm = bmesh.new()

def get_range(start, end, decimal=0.01, step=1):
    return [v * decimal for v in range(int(start / decimal), int(end / decimal) + 1, step)]

def equation(x, y, z):
    return x**2 + y**2 + z**2 + m.sin(4*x) + m.sin(4*y) + m.sin(4*z) - 1

tolerance = 0.1

for x in get_range(-1, 1):
    for y in get_range(-1, 1):
        for z in get_range(-1, 1):
            result = equation(x, y, z)
            if abs(result) < tolerance:
                v = bm.verts.new((x, y, z))

bm.to_mesh(mesh)
bm.free()

This creates the following point cloud:

Then you can easily convert this cloud into a real mesh with Points to Volume node as demonstrated in the following Geometry Nodes setup:

And optionally add a Smooth modifier with high iteration to get smoother result:

Great Idea, but even i like the python way, - with your first answer you can adjust the math parameter more flexible only with drag and drop. Here, one have to change the script and run it again. But, this way opens also the possibility to work with complex numbers, that isn´t possible in GN Setup. so great again !

@smice yeah there are always pros and cons for different methods. the important thing is we know what is possible so we know how we can approach the problem at different angles and use the solution that best satisfies the requirements of our problem :D


text:
Blender Video Sequence editor taking all memory and crashing
My computer has 8 GB RAM but is not able to render a 720p 2D video in Blender but my older computer was able to render much heavier videos, having only 4GB Ram; I was running Windows and Sony Vegas then but my new system is running on Linux.
I wonder if I must be doing someting wrong on my render settings, or if not, if there is another way of editing not heavy videos using Blender running on a pc with about 8gb RAM.
Please watch my video, at least some of it in which I explain my problem
https://www.youtube.com/watch?v=YKqcFmzKE5M if you need any additional information.

On the User Preferences, System tab there should be a 'Sequencer/Clip Editor' setting - what is that set to? On my system it seems to be defaulted to 1024Mb (ie, 1GB) and this should limit how much memory blender allocates to the video sequence editor.

Do you mean I should increase this value? (Hope I understood ir right)

Not increase - but possibly decrease. From your video Blender appears to be using all of your physical memory (8Gb) along with all of your free swap - so upwards of, say 12Gb. The parameter is to limit the amount of memory allocated in certain situations so if it's already set to 1Gb then it's obviously not doing its job - or the memory is being allocated by something not covered by that parameter. If, however, it's currently set to, say, 20Gb then that could certainly be a cause and dropping it to, say, 4Gb (half your physical memory) might help.

I opened the User Preferences > System and noticed that my "Sequencer / Clip Editor:" was set to 24273 ! I will change it to something about Gb and tell you the results. Thanks

Thanks a lot! my problem is solved!
I changed the "Sequencer" to 2048. The video was rendered completely and my computer didn't crash.
But this "Sequencer / Clip Editor" Field seems to be the ammount of memory which is NOT used during the rendering.  During rendering I opened the System Monitor, and noticed that the memory usage, never exceeded 5,3 of my 7,3 GiB Ram. It seems that this 2Gb that I set, are the amount of memory which is left to be unused.
Strangely my Swap memory wasn't used at all during all the time.
But anyways. thanks a lot!

Glad your problem is resolved. I'm not sure why it would appear to be setting the 'free' memory - I suppose it must either be coincidence (and other processes are taking 3.3Gb and Blender the other 2Gb) or a bug (with Blender not calculating the correct amount of memory to use) - perhaps you could re-try with a different amount (eg, 3Gb) and see if the figures hold. If this is proven to be a bug then you could report it to see if it can be addressed. I've updated your question to make it clear as to the memory usage causing the crash and added an answer explaining the solution.

Blender include a setting in the User Preferences/System tab to limit the amount of memory that the Video Sequence Editor can use. This setting should be never set to more than your available system memory plus the available swap - otherwise Blender can attempt to grab more memory than is available and cause the system to crash or become unresponsive.
At the bottom of the System tab in User Preferences is a 'Sequencer/Clip Editor' setting that dictates the memory limit for blender when caching and rendering videos in the VSE. This setting normally defaults to 1024Mb - ie, 1Gb - and so should not cause a problem (unless your system has less than 1Gb of available memory). If this is set to a value that is larger than your system memory - or less than your 'free' memory when Blender is not running - then you may get Blender trying to allocate more memory than is available.
Reduce the value to limit the amount of memory available to Blender.

I am also not very expert in blender but i noticed a couple of things that can work for u i think,
1. Render animation frame by frame by selecting a folder and select output as any image type. And i think this is the main cause of crashing .
I think this will solve your problem . but still there is  some  thing that u can do.
2. Under the performance tab change the till size to 16×16 if u are rendering by cpu and for graphics card i think its 256× 256 ( not sure check google )
3 You can reduce samples


text:
How to move 2 cube at the same time? New to Blender
I wanted to make an animation. I added two box and I made one of the box rotates about a circle. For some reason, the other box follows the 3-axis intersected at the other box,instead of staying at the origin. What did I do wrong? Thank you.
import bpy
import math

if not 'Cube' in bpy.data.objects:
    bpy.ops.mesh.primitive_cube_add()

if not 'Cube2' in bpy.data.objects:
    bpy.ops.mesh.primitive_cube_add()

fpr = 120.0
step_size = 2*math.pi / fpr

radius=5

def set_object_location(n):
    x = math.sin(n) * radius
    y = math.cos(n) * radius
    z = 0.0
    ob = bpy.data.objects.get("Cube")
    ob.location = (x, y, z)
    obs = bpy.data.objects.get("Cube.001")
    obs.location = (0, 0, 0)

def update(scene):
    frame = scene.frame_current
    angle = frame % fpr

    if angle == 0:
        set_object_location(angle)
    else:
        set_object_location(angle*step_size)

bpy.app.handlers.frame_change_pre.append(update)

The problem is that you assign a fixed position to the 2nd cube:
 obs = bpy.data.objects.get("Cube.001")
 obs.location = (0, 0, 0)

To be able to move them independendly you could add all objects to a list and move them while iterating:
if not 'Cube' in bpy.data.objects:
    bpy.ops.mesh.primitive_cube_add()

if not 'Cube.001' in bpy.data.objects:
    bpy.ops.mesh.primitive_cube_add()

ob = bpy.data.objects.get("Cube")
ob2 = bpy.data.objects.get("Cube.001")
obs = [ob,ob2]

fpr = 120.0
step_size = 2*math.pi / fpr

radius=5

def set_object_location(ob,n):
    x = math.sin(n) * radius
    y = math.cos(n) * radius
    z = 0.0
    ob.location = (x, y, z)

def update(scene):
    frame = scene.frame_current
    angle = frame % fpr

    count=0.0
    for ob in obs:
        if angle == 0:
            set_object_location(ob,angle+count)
        else:
            set_object_location(ob,angle*(step_size+count))
        count = count + step_size

bpy.app.handlers.frame_change_pre.append(update)

Your code seems to work for me - one cube rotates around the other (which remains stationary at the origin). The only issue I can see with the code is that the initialisation to add the cubes refers to 'Cube' and 'Cube2' but the later logic refers to 'Cube' and 'Cube.001'.
I suspect the most likely cause of your issues is that you have run the script multiple time and, perhaps, an earlier copy of your code is still registered in the handler. Try saving your work (after changing 'Cube2' to match 'Cube.001'), closing Blender, and re-opening and running - and see if that resolves your problem.


text:
Need help with soft body physics for noodle legs character
I've been trying to figure out how to recreate this character animation in Blender.
https://www.instagram.com/p/BU8x8TNhQbW/?taken-by=laurierowan

But I just can't figure out how to do it.. I have made the noodle legs with "Bezier Curves" and added "Soft Body" physics to them, so they look pretty much identical to the video I linked above.
My main problem is that I don't know how I can make the character's body attach to the noodle legs, and should the character's body be a "Soft Body" or "Riggid Body"?
Is it even possible to connect "Soft Bodies" to "Riggid Bodies"? Or is there another way to recreate this video?
Any help is highly appreciated!
I've been using Blender for modelling for around 1 year now, but just recently started experimenting with animation physics.

Very similar to the setup for this answer https://blender.stackexchange.com/a/93623/29586, in particular https://i.sstatic.net/pHRos.gif. You can pin the soft body to the rigid using the Goal as also described in the above answer (pinning to a spindle). If this doesn’t get you most of the way there I should be able to provide a proper more detailed answer when time allows.

You can use the Soft Body Goal in conjunction with a Vertex Group to 'pin' one or more vertex to the 'body' of the character - either directly (using Hook to Selected) or via an Empty.
Start by creating your character's body - in my case I'll stick with the default cube.
Create a leg as a string of vertices. The simplest way of achieving this is to add a Curve/Path and convert it to a mesh (select it and go to Object/Convert To/Mesh. Position it and scale it so that it is roughly in place. Add a plane for the floor, make it a Passive Rigid Body, and add Collision in the physics panel.

Select the 'leg' and subdivide it so it's got sufficient vertices to bend realistically but don't subdivide too much - the distance between vertices should ideally be comparable to the eventual 'thickness' of the 'legs'.

Next, in Edit mode (Tab), select the vertex at the top of the leg, press Control+H, for the Hook menu, and select Hook to New Object. This will create an Empty and hook the selected vertex to it.

While that single vertex is still selected go to the Mesh properties panel, add a new Vertex Group (click the '+') and Assign that vertex to the group. You can rename the Vertex Group to something appropriate by double clicking it and typing the new name (eg, 'Pin').

Swap back to Object mode (Tab), select the Empty, hold down Shift and select the 'body' - so that both are selected, and Control+P and Set Parent to Object to parent the empty to the 'body'. Moving the 'body' should now drag the vertex along with it. Move the 'leg' in position so it starts the simulation in the correct place.
Select the 'leg' and add Soft Body in the Physics panel. In the Soft Body Goal, set the Vertex Group to the 'pin' vertex group you created earlier. Set Soft Body Goal Strength and Goal Stiffness to their maximum values to bind the vertex strongly to the parent - the other vertices will be affected only by the Soft Body simulation.

Add Active Rigid Body physics to the 'body' or animate it with keyframes. The soft body leg will follow the motion of the 'body', pinned by the single vertex. You can add some variation to the leg (which assists with it 'folding' rather than getting stuck in a vertical line of perfectly aligned vertices) by selecting all vertices in Edit mode and selecting 'Randomize' in the Tool panel and setting a suitably small Amount of random variation.

Adjust the Soft Body Edges properties to tune the begaviour and stretchiness of the soft body. For example, increase the Pull spring strength to 0.9999 and maybe increase Bending Spring to, say, 0.5 to give the leg some resistance to bending. Also consider enabling Edge collision so edges don't pass through sharp edges of rigid bodies.

To give the leg some thickness, enable Soft Body Self Collision. The self-collision is based around a series of spheres around each vertex that repel other vertices. The size of the 'collision ball' around each vertex is usually based on the length of the edges connected - setting the Calculation to 'Average' will use the average spring length for the radius of the collision sphere and this is further adjusted by the Ball Size setting. Setting this to 0.45 (the default) and Average (the default) results effectively in spheres along the length of the soft body leg that almost touch when the leg is straight. This should give reasonable results providing the distance between the vertices are of a similar length to the intended thickness of the leg -  otherwise adjust the Ball Size until you get the desired effect. Note, however, that ball sizes > 1.0 can produce strange effects since the ball will be larger than the neighbouring edge and will push away the adjacent vertices. If this occurs, reduce the number of vertices (so the spacing is close to the desired thickness of the soft body) and try again.
To generate a mesh around the 'leg' add a Skin modifier followed by a Subdivision Surface modifiers. To adjust the thickness of the 'skin', go into Edit mode, select all vertices (A) and press Ctrl+A or manually adjust the Mean Radius X/Y properties in the Properties panel (N). You can also add an additional Subdivision Surface modifier before the Skin to add additional smoothness to the coils (otherwise it can appear a bit angular).

Duplicate the same for the other 'leg'. Add Collision to the 'body' and adjust the collision on the 'body' and the 'floor' to set the 'Outer' Soft Body margin to match the thickness radius of the 'leg' - this will result in the appearance that the outer surface of the 'leg' collides with the surface (since it's actually the vertex that performs the collision, setting the 'Outer' to the radius of the soft body gives the surface a collision distance that matches what would occur if it were the outer edge of the soft body that was colliding).

Note : If you get strange behaviour with the soft body after changing the 'Hook' or the Soft Body settings, c heck the sequence of your modifiers since the order is very important. You should always have the Hook first, followed by the Soft Body, followed by the geometry modifiers (ie, Subsurface, Skin, etc.). In my case I used Hook, Soft Body, Subsurface (set to level '1' to smooth out the bends in the leg), Skin, Subsurface (set to level '2' to smooth out the Skin). It can also help to adjust the Soft Body Solver settings - decrease Error Limit (eg, from 0.1 to 0.01) and try increasing the Min Step (eg, 10 to 40) - vary one setting at a time and re-run the simulation to evaluate how this affects the simulation.
Blend file (free all bakes and re-run the animation to rebuild the Soft Body Cache) :


text:
Weird anomalies with mesh deform
I've applied mesh deform on my mesh and I'm getting some strange results

I'm absolutely sure there are no intersecting faces and it seems that my deform mesh only affects certain vertices of my mesh

could you please tell a bit more, maybe share your file before you applied the modifier

@moonboots https://drive.google.com/open?id=1QrG4rgIA6HMMwmWgI6einnIeW1YKInqe here you go. I moved the deform to be the 1st modifier after the save

I think your meshes are a bit too complicated, too many vertices etc... For example, if I simplify the MeshDeform modifier cage, it works correctly:

how would i rig the fingers then? those are a bit tricky. any tips? is it possible to make seperate meshes just for the fingers/feet?

what do you mean? your problem had nothing to do with rigging

sorry, i constructed the question wrong. how would i go on to make simpler fingers for my deformer. I'm using the deform modifier to rig the high poly mesh and i want to be able to rig the fingers, but it really wouldnt be able to do that if i make the deformer mesh too simple

I might be wrong but I think you're going the wrong way, a mesh modifier could be useful sometimes for rigging, especially to avoid clothes overlapping, but for an object like your dragon, why don't you rig it in a classical way? I thought your mesh deform was just to adjust its shape a bit...

i was told that the best way to rig high poly objects (my mesh has around 10mil verts) is to use the mesh deform modifier. I was following the zach reinhardt's course on udemy and he did it this way. although, now i realize that he did it because he had too much parented objects... anyways, thanks for the help

I never heard that but I'm still not a 3D champion, maybe he has his reasons, but maybe first try the classical way, also try to work with less polygones, i.e. try to simplify your mesh, for example multiresolution is interesting but you need to bake it to a lower poly version

yeah, i did that, then i stored the shrinkwrap data into it


text:
.STL Files in Blender to be used for an animation. Should I recreate them in blender?
Here is a scene I'm using as a reference.
https://ibb.co/n9Yub8
Here a portion of a trailer assembly not fully finished using for reference to show what i mean.
https://ibb.co/d3r0io
One of the trailers alone has 673,475 tris / 269,538 faces / 428,851 verts,
and its not even fully finished yet its about 25% complete and there will be from 4-6 of them in the scene alone not including everything else.
Here is how the frame looks like in edit mode.
https://ibb.co/hapWpT
So before i continue should i just recreate everything in blender or is there a way to reduce the amount of vertices?
I just don't want to waste time placing everything and my computer giving up.

I've used the edge split modifier with the smooth shading tool, limited dissolve, remove doubles.

Have you tried the decimate modifier? It should help you reduce triangles quite a bit on planar faces

I do not think there is easy way, start by removing doubles link,then check all other technics in the link, start cleaning it manually, then it is more time management. If you think that  cleaning it manual is more time consuming tha building it, build it.


text:
Gaps in Texture Baking
I am having a problem with texture baking and I have not been able to find a solution.  When the texture is baked, some of the islands do not line up perfectly with the new texture. I have tried changing so many different options, but still keep having the same problem.  I have also tried unwrapping it in different ways, too.
Unfortunately if I just increase the margin (in the bake settings) the islands are fully filled, but if there is more then one color in the island the added pixels get their colors blended.

Zoomed in.  Texture not aligned with islands (margins set at 0).

This is what I get if I add margins to the texture bake.
I get interpolated colors inside island. Here the top portion is inside island. The only two colors should be white and pink. However the pixels added are interpolated colors. Notice the two pixels that are slightly inside the island that were added as I increased the margin.
Anyone have any suggestions for me?


text:
frame_change_post/pre not working when Rendering Animation
I've got this script file that works flawlessly in the viewport, but stops completely when I start rendering it as an Animation.
import bpy
import math

def my_handler(scene):
    print('testing') # this will be printed out 3 times each frame when rendering the animation, but once only in the viewport.
    #assigning variables to objects
    a=bpy.data.objects['EmptyTop']
    b=bpy.data.objects['EmptyRight']
    text=bpy.data.objects['TextRightSide']

    # formula for calculating distance
    distance=str(int(math.hypot(a.location.x - b.location.x, a.location.y - b.location.y)*10))
    text.data.body=distance

bpy.app.handlers.frame_change_post.append(my_handler)

(my_handler) is refreshed every frame as I've tested it by printing a test text in it. However, the main problem is that it does not do anything with the next code (bpy.data.objects). I've tried to change (bpy.data) to (scene) as shown
import bpy
import math

def my_handler(scene):
    print('testing')
    #assigning variables to objects
    a=scene.objects['EmptyTop']
    b=scene.objects['EmptyRight']
    text=scene.objects['TextRightSide']

    # formula for calculating distance
    distance=str(int(math.hypot(a.location.x - b.location.x, a.location.y - b.location.y)*10))
    text.data.body=distance

bpy.app.handlers.frame_change_post.append(my_handler)

Worked just fine in the viewport but gave me this message when rendering the it as An animation
(line 7, in my_handler
KeyError: 'bpy_prop_collection[key]: key "EmptyTop" not found')

Sooo, what should I do now to make it work?

Rendering as stills eg https://blender.stackexchange.com/questions/110662/a-script-to-render-each-frame-as-image-not-render-animation-in-2-8 will work with handler as is.

that worked for me. Thanks a lot!


text:
Intersecting transparent object causing artifacts in cycles
When two objects -one of them transparent- intersects it creates some artifacts visible even in the alpha channel. Even with 1024 transparent bounces the artifacts remain.

In the example file there are two cubes in the same position, one transparent and one emission.

What is causing this? Any way to get rid of this artifacts?

That is considered a bad modelling practice, never have two perfectly coplanar faces, transparent or otherwise. What is the point of having overlapping objects anyway?

This is a limitation of many render engines. In OpenGL/DirectX applications it is typically known as z-fighting. The simple answer is to not do this - don't put two surfaces in the exact same place. This is a scenario that's impossible in real life (no two solid objects can share the same location) and therefore typically not taken into account when designing render engines.

Even though one of them is transparent?

Yes, even then. Many Ray tracers first find the closest surface to the camera, and only after that they calculate its shading. Since the Ray tracer won't tell two surfaces apart that are in the same location, only one of them will get shaded. Which one of the two it is (the opaque or the transparent) is in this case left to chance.

Think of it this way:
If the transparent object wasn't fully transparent but semitransparent and tinted (let's say blue glass), what is the expected result in your case? Should you see the opaque surface through the blue glass or should the opaque surface cover the blue glass? There is no correct answer to this question in real life, as the situation is impossible in real life. A render engine built to simulate reality is not designed to handle cases that cannot exist in reality.

Yeah, I got it with the preview answer :P Thanks!


text:
How does hair particle friction work?
I am trying to get a collision and friction between hair particles but I couldn't find a way to do it. Can anybody help with these test files please?

Reference:
https://www.youtube.com/watch?t=17&v=1zdgV_oiJMU

[![my result][1]][1]
1)The hairs can do hair self collisions only in the same hair particle system! In your example you have two hair systems
2)Internal friction has to be set to 0.2 - 0.8 range.
3) density target slider controls collision margin smaller values equal smaller collision distance. Be careful ! values set too low will cause hair explosions.
4)Strength value (ALWAYS) has to be set to ((1)) unless you want interesting hair strands.
5) Voxel grid cell size optimal value 0.040
blendfile


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How to render particle hairs in cycles?
I have created a hairstyle with the hair particle system. I can't render the exact style in final render, but I can render that in openGL.

Could you upload a .blend file to a service like Blend-Exchange and post the link in your question? It would helps us a lot, many critical options are minimized so we can't check their values.

 Here , i have attached the blend file, please have a look.

Paste that in the question instead please . . .

I have found the solution for my question.
Increase steps value to above 6 or 8 in particle render tab.

To get all details of hair style, steps value should be high.

Cycles animation engine doesn't show particles in render. Unlike in blender engine were a particle shows up as a signal pixel. The best way to fix your problem is to turn your particles to object in under render options(halo, line, ect.)Under the particle system

cycles can render hair particles.


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Assign Material Slot to no material via python
I'd like to, in code, remove a material from a material slot without deleting that material slot (because deleting it would remove the connections between that material slot and the vertices). The only code I've found that can remove materials also deletes the material slot: bpy.ops.object.material_slot_remove()
I've also tried to use the property_unset function in the material slot, but it just doesn't seem to do anything. For example: C.object.material_slots[0].property_unset('material')
Setting the material to something else is fairly straightforward, but setting it to NULL seems impossible, even though it's easy to do via the interface.
This is related to, but not solved by:Python - Set material to material slot

Its as easy as bpy.context.object.data.materials[0] = None. Check this answer How to assign a new material to an object in the scene from Python? to see why and how it works.

This is awesome. Thanks! I suppose the None object can be used in a variety of circumstances