Inflate tool for Dynamic Topology creates extra geometry that blobs out the backside of the mesh. #38121

New Issue

marc dion · 2014-01-08T09:47:42+01:00

marc dion commented

2014-01-08 09:47:42 +01:00

System Information
OSX 10.9.1

Blender Version
I noticed the issue using build 54ebaad and confirmed it for the official 2.69.0 r60991 release as well.

Short description of error

Create a plane, go to Sculpt, activate Dynamic then set the Inflate/Deflate brush to 1.0.
Draw out a few strokes, and you should now expect to see messy blobs of geometry built up on the backside of the mesh.
For me this has worked every time I tried to do it. I reset to factory defaults for both builds and it still happens.

One quick test showed that the tumors that form can end up having an absurdly high poly count.
On an area that only had about 5000 triangles, the extra blobs that were formed made up about 35000 triangles.

I tried to attach a .blend file but I received an error message that the file size limit was exceeded. (.blend ~7.5MB)

**System Information** OSX 10.9.1 **Blender Version** I noticed the issue using build 54ebaad and confirmed it for the official 2.69.0 r60991 release as well. **Short description of error** Create a plane, go to Sculpt, activate Dynamic then set the Inflate/Deflate brush to 1.0. Draw out a few strokes, and you should now expect to see messy blobs of geometry built up on the backside of the mesh. For me this has worked every time I tried to do it. I reset to factory defaults for both builds and it still happens. One quick test showed that the tumors that form can end up having an absurdly high poly count. On an area that only had about 5000 triangles, the extra blobs that were formed made up about 35000 triangles. I tried to attach a .blend file but I received an error message that the file size limit was exceeded. (.blend ~7.5MB) ![Inflate.png](https://archive.blender.org/developer/F63794/Inflate.png)

marc dion commented

2014-01-08 09:47:42 +01:00

Changed status to: 'Open'

marc dion commented

2014-01-08 09:47:42 +01:00

Added subscriber: @MarcClintDion

Warren Bahler commented

2014-01-08 16:39:40 +01:00

Added subscriber: @WarrenBahler

Warren Bahler commented

2014-01-08 16:39:40 +01:00

I could be wrong but I don't think its a bug, its just that the inflate brush expands faces based on there normal, so as soon as dynamic topology creates a face pointing downward, it goes crazy with the opposing normals.using the smooth brush frequently during the sculpt helps prevent this.

I find that the inflate brush works best on manifold meshes, for a flat plane, I'd use the draw brush to block out the shape, then refine it with the other brushes.

hope that helps...

I could be wrong but I don't think its a bug, its just that the inflate brush expands faces based on there normal, so as soon as dynamic topology creates a face pointing downward, it goes crazy with the opposing normals.using the smooth brush frequently during the sculpt helps prevent this. I find that the inflate brush works best on manifold meshes, for a flat plane, I'd use the draw brush to block out the shape, then refine it with the other brushes. hope that helps... ```

Brecht Van Lommel commented

2014-01-08 17:08:24 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2014-01-08 17:08:24 +01:00

We really need a .blend file to reproduce the issue. If it's too big you could try uploading on pasteall, or removing parts of the mesh or other data in the .blend file that does not influence the bug.

marc dion commented

2014-01-09 08:43:28 +01:00

I'll do the paste all thing. For future reference, what is the file size limit for this site?

marc dion commented

2014-01-09 08:47:13 +01:00

http://www.pasteall.org/blend/26182

Brecht Van Lommel commented

2014-01-22 17:29:08 +01:00

The limit is 5mb. I can confirm the problem, I'm not sure how difficult it is to fix but the random flipped faces seems like they shouldn't be happening.