Bevel tool produces unwanted distortion with "skewed" meshes #33906

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Moolah Nasreddin · 2013-01-17T13:59:24+01:00

Moolah Nasreddin commented

2013-01-17 13:59:24 +01:00

%%%--- Operating System, Graphics card ---

WinXP SP3, 32bit, NV GeForce GTS 450

- Blender version with error, and version that worked ---

r53873, don't remember if it worked properly because the tool is almost new

- Short description of error ---

Bevel with Segments more than 1 (so it's rounded) produces very noticeable distortions of the source flat surfaces. Saying simpler: what was flat becomes "not flat" but intended to be flat.

- Steps for others to reproduce the error (preferably based on attached .blend file) ---

activate Bevel
make it's Offset 1.0 or bigger (so the artifact will be really noticeable)
increase the number of segments (more than 1)

From the view in my .blend (Front Ortho) it becomes visible how it makes an undesirable "arc" in X direction.

This doesn't happens with a simple cube like forms or any meshes where adjacent faces forms 90 degree angle.

P.S. It's not crucial when you're making some organic forms or really "freestyle" designs without thinking of some precision. But for making some "flat" vehicles for games (as an example) it becomes a "time eater". Currently I use round_bevel script for this job but it's buggy, leaves some new unwanted faces and crashes sometimes. BUT it's bevel works perfectly in such cases. So maybe it can be a clue for this...

Thanks for you work, guys! :)%%%

%%%--- Operating System, Graphics card --- WinXP SP3, 32bit, NV GeForce GTS 450 - Blender version with error, and version that worked --- r53873, don't remember if it worked properly because the tool is almost new - Short description of error --- Bevel with Segments more than 1 (so it's rounded) produces very noticeable distortions of the source flat surfaces. Saying simpler: what was flat becomes "not flat" but intended to be flat. - Steps for others to reproduce the error (preferably based on attached .blend file) --- - activate Bevel - make it's Offset 1.0 or bigger (so the artifact will be really noticeable) - increase the number of segments (more than 1) From the view in my .blend (Front Ortho) it becomes visible how it makes an undesirable "arc" in X direction. This doesn't happens with a simple cube like forms or any meshes where adjacent faces forms 90 degree angle. P.S. It's not crucial when you're making some organic forms or really "freestyle" designs without thinking of some precision. But for making some "flat" vehicles for games (as an example) it becomes a "time eater". Currently I use round_bevel script for this job but it's buggy, leaves some new unwanted faces and crashes sometimes. BUT it's bevel works perfectly in such cases. So maybe it can be a clue for this... Thanks for you work, guys! :)%%%

Moolah Nasreddin commented

2013-01-17 13:59:24 +01:00

Changed status to: 'Open'

Howard Trickey commented

2013-01-17 14:58:21 +01:00

%%%Thanks, I see the problem. Will work on a fix, but not immediately (something else on the top of my things-to-work on in fixing bevel).
%%%

%%%Thanks, I see the problem. Will work on a fix, but not immediately (something else on the top of my things-to-work on in fixing bevel). %%%

Howard Trickey commented

2013-01-31 13:54:43 +01:00

%%%Fixed in svn, r54231.%%%

Howard Trickey commented

2013-01-31 13:54:43 +01:00

Changed status from 'Open' to: 'Resolved'

Howard Trickey closed this issue

2013-01-31 13:54:43 +01:00

Moolah Nasreddin commented

2013-02-01 15:17:35 +01:00

%%%Hi, Howard!
Thank you! Now it works in simple cases.

I think maybe you know about another problem but for some case I'm attaching the new file.

Bevel_distorts_Mesh_2.blend
There if you'll bevel selected loops it will give distorted surfaces and wrong forms of circles (bevel shape).

I thought about the design...
Check approach_thought1.blend

When you scale points "B" and "C" about the Cursor they "prove" the flatness of the "formed" faces around point "A".
So there is the angle "A-Cursor-B" - these edges form the triangle (at least virtually). And there is the virtual angle "D"="LocalZAxis-Cursor-B"
If we'll set the Cursor to "A" so it will be the Cursor now and there will be the new "A", "B" and "C" (adjacent points). So here will be new "D"="D2"
And obviously if it's equal to D than the face is planar. By the same approach can be checked the face on another side of the edge to be beveled.

The idea is that bevel components here can be flattened (or projected probably) on these faces if they (faces) are flat.

I'm not a math-pro (surely) but I suppose that for other issues like non-round arcs this probably requires some functions to calculate tangency of the future "slices".

Sorry if I give some not smart advices but these are just my ideas.%%%

%%%Hi, Howard! Thank you! Now it works in simple cases. I think maybe you know about another problem but for some case I'm attaching the new file. Bevel_distorts_Mesh_2.blend There if you'll bevel selected loops it will give distorted surfaces and wrong forms of circles (bevel shape). I thought about the design... Check approach_thought1.blend When you scale points "B" and "C" about the Cursor they "prove" the flatness of the "formed" faces around point "A". So there is the angle "A-Cursor-B" - these edges form the triangle (at least virtually). And there is the virtual angle "D"="LocalZAxis-Cursor-B" If we'll set the Cursor to "A" so it will be the Cursor now and there will be the new "A", "B" and "C" (adjacent points). So here will be new "D"="[D2](https://archive.blender.org/developer/D2)" And obviously if it's equal to D than the face is planar. By the same approach can be checked the face on another side of the edge to be beveled. The idea is that bevel components here can be flattened (or projected probably) on these faces if they (faces) are flat. I'm not a math-pro (surely) but I suppose that for other issues like non-round arcs this probably requires some functions to calculate tangency of the future "slices". Sorry if I give some not smart advices but these are just my ideas.%%%

Moolah Nasreddin commented

2013-02-01 16:07:07 +01:00

%%%P.S. Sorry for bothering you...
Just in a case that maybe you didn't seen this (I can't be 100% sure you did):

https://github.com/Obijuan/obiscad

There is the Bevel module. I've looked into it but didn't understood a lot :D There is some code (not a lot). Maybe you'll get some ideas looking into it.%%%

%%%P.S. Sorry for bothering you... Just in a case that maybe you didn't seen this (I can't be 100% sure you did): https://github.com/Obijuan/obiscad There is the Bevel module. I've looked into it but didn't understood a lot :D There is some code (not a lot). Maybe you'll get some ideas looking into it.%%%

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Bevel tool produces unwanted distortion with "skewed" meshes #33906