Assigning UV for aniso tangent hangs Blender when rendering starts. Probably in rare cases only. #49384

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CarlG · 2016-09-17T17:38:33+02:00

CarlG commented

2016-09-17 17:38:33 +02:00

CrashObject.blend
Attached file (also avail here if it doesn't work will hang Blender, and have at least one confirmation that it happens to others. Not sure what is wrong with it, but will hang Blender when doing the steps below:

Initiate screen render in lower right window with shift+z.
In the material window, switch from radial mode to UV map.
Instant hang, the selection doesn't even update. If render was not initialized, Blender will allow switching to UV based, but will hang once you start rendering.

CPU/GPU doesn't matter. Something went kind of awry when I made of the "lamps", in that when I enabled subsurf (>0) some faces just wouldn't show up. Normals seemed okay, no doubles, everything unhid, no verts seemed loose, and I could select and move the face. I had to delete a few loops and recreate them to get it back. That's the first time that has ever happened to me (I build it on the Disney version, not sure if it matters), and I've had no issues before using UV based tangents. That's no guarantee though that I didn't mess up this time.

Both objects was previously operated like this:

Part of tube was separated to own object.
Merged loops to form single points, points merged.
Converted the mesh (now basically a curve of vertices) to a curve object.
Reshaped, points added, smoothed etc.
Added thickness to it and converted back to mesh.
Merged with object it came from.
UV Unwrapped to form a nice square suitable for UV tangents.
Added subsurf (not 100% sure I did it here of if it existed beforehand). Now I noted the missing part and fixed that.

The converting mesh->curve->edit&refine->mesh process has caused frequent crashes, and also did it this time. On next restart everything seem normal again and conversion process will work. I believe the full mesh isn't UV unwrapped, but it would still crash if I select all and did a simple unwrap.

Bug as posted on blenderartists:
https://blenderartists.org/forum/showthread.php?406850-Blender-2-78-Release-Candidate-2&p=3099588&viewfull=1#post3099588

Tested on 2.78RC2, one Disney shader build (which is the one I use most often) and others. Seems to be something that's been around for a while, but it's the first time it has struck me (and I'm usually using UV based tangents for aniso shading).

I'm suspecting something in the data structure to be partly cause, because of what happened to my mesh during the editing process. Not the UV tangent command itself, but what it reads from attached file.

[CrashObject.blend](https://archive.blender.org/developer/F361803/CrashObject.blend) Attached file (also avail [here ](http://pasteall.org/blend/index.php?id=43612) if it doesn't work will hang Blender, and have at least one confirmation that it happens to others. Not sure what is wrong with it, but will hang Blender when doing the steps below: 1) Initiate screen render in lower right window with shift+z. 2) In the material window, switch from radial mode to UV map. Instant hang, the selection doesn't even update. If render was not initialized, Blender will allow switching to UV based, but will hang once you start rendering. CPU/GPU doesn't matter. Something went kind of awry when I made of the "lamps", in that when I enabled subsurf (>0) some faces just wouldn't show up. Normals seemed okay, no doubles, everything unhid, no verts seemed loose, and I could select and move the face. I had to delete a few loops and recreate them to get it back. That's the first time that has ever happened to me (I build it on the Disney version, not sure if it matters), and I've had no issues before using UV based tangents. That's no guarantee though that I didn't mess up this time. Both objects was previously operated like this: 1) Part of tube was separated to own object. 2) Merged loops to form single points, points merged. 3) Converted the mesh (now basically a curve of vertices) to a curve object. 4) Reshaped, points added, smoothed etc. 5) Added thickness to it and converted back to mesh. 6) Merged with object it came from. 7) UV Unwrapped to form a nice square suitable for UV tangents. 8) Added subsurf (not 100% sure I did it here of if it existed beforehand). Now I noted the missing part and fixed that. The converting mesh->curve->edit&refine->mesh process has caused frequent crashes, and also did it this time. On next restart everything seem normal again and conversion process will work. I believe the full mesh isn't UV unwrapped, but it would still crash if I select all and did a simple unwrap. Bug as posted on blenderartists: https://blenderartists.org/forum/showthread.php?406850-Blender-2-78-Release-Candidate-2&p=3099588&viewfull=1#post3099588 Tested on 2.78RC2, one Disney shader build (which is the one I use most often) and others. Seems to be something that's been around for a while, but it's the first time it has struck me (and I'm usually using UV based tangents for aniso shading). I'm suspecting something in the data structure to be partly cause, because of what happened to my mesh during the editing process. Not the UV tangent command itself, but what it reads from attached file.

CarlG commented

2016-09-17 17:38:33 +02:00

Changed status to: 'Open'

CarlG commented

2016-09-17 17:38:33 +02:00

Added subscriber: @CarlG

Brecht Van Lommel commented

2016-09-17 21:33:07 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2016-09-17 21:33:07 +02:00

Confirmed. In fact Blender internal crashes as well if you use a tangent space normal map with this mesh, it uses the same mikktspace library as Cycles.

Brecht Van Lommel commented

2016-09-17 22:27:59 +02:00

This mesh has NaN vertices. If you select all vertices and look in the 3D view Transform panel you can see this. We can fix the crash for this specific case, but the main bug is in the tool that led to these NaNs, and being able to reproduce that from scratch will probably not be possible.

blender-admin commented

2016-09-18 13:06:15 +02:00

This issue was referenced by 0552d5820b

This issue was referenced by 0552d5820b70d2bc60a703af23cdea6828317ab4

Brecht Van Lommel commented

2016-09-18 13:39:12 +02:00

Crash fixed now.

If you can find a way to create NaN vertices you can create a new bug report. The simple way to fix this existing mesh is to select all visible vertices with something like border select or linked select, then invert the selection to delete the NaN vertices.

Crash fixed now. If you can find a way to create NaN vertices you can create a new bug report. The simple way to fix this existing mesh is to select all visible vertices with something like border select or linked select, then invert the selection to delete the NaN vertices.

Brecht Van Lommel commented

2016-09-18 13:41:06 +02:00

Changed status from 'Open' to: 'Resolved'

Brecht Van Lommel closed this issue

2016-09-18 13:41:06 +02:00

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Assigning UV for aniso tangent hangs Blender when rendering starts. Probably in rare cases only. #49384