0001233: Unable to process a scene using DAZ 3D Millenium Dragon 2

(0003412)
Lord Crc (administrator)
2012-05-15 15:17

From what I can gather, issue 1 is due to numerical issues. It seems some of the vertices are just too close to each other.

In at least one case a subdivided vertex, which should be between the two source vertices, actually ends up being located at the exact position of one of the source vertices.

This creates a degenerate triangle which the code fails to identify and handle.

I haven't looked into issue 2 yet.

(0003413)
AGriffiths (reporter)
2012-05-15 23:27

Thanks for the feedback. That makes sense - The SPIKES are set to a value of 0 which morphs them to a position where the are not seen. So by setting the parameter to 0.001 was just enough to avoid that issue. I guess that the rotation/scale of the character must have played a big factor in causing this as well. That would be called Murphy's law.

Thanks,
Andy

(0003440)
AGriffiths (reporter)
2012-06-23 10:42
edited on: 2012-06-23 10:43

Not wishing to be a pain, but has there been any progress on these issues?

Lookng forward to trying this scene out with Lux, but need the fixes.

Cheers,
Andy

(0003441)
Lord Crc (administrator)
2012-06-27 02:35
edited on: 2012-06-27 02:48

Unfortunately this is a tricky issue.

I managed to change some code so that it handles the numerical precision issues better, however this is just a bandaid fix.

I would like to make the code properly handle degenerate edges, so that it will never crash for geometry like yours. I'm still working on that.

The fix for issue 1 may or may not solve issue 2, so I will have to wait with the investigation into that until 1 is resolved.

(0003442)
AGriffiths (reporter)
2012-06-27 08:37

Much appreciated - thanks for the update.

Cheers,
Andy

(0003458)
Lord Crc (administrator)
2012-07-05 02:56

I think I'll solve issue 1 by detecting the erroneous condition and simply prevent further subdivision. We may later make the code more robust to these conditions, however for now this should prevent the infinite loops.

I've not yet figured out exactly how to handle issue 2. I know what the problem is, so hopefully I can figure out something soon.

(0003459)
AGriffiths (reporter)
2012-07-05 19:44

Thanks for the update - much appreciated.

(0003941)
jeanphi (administrator)
2013-05-21 14:33

Issue 1 should now be fixed (I can render the scene here in GPU mode.
Issue 2 seems to be fixed too, Lux now aborts with a nice error message when doing hybrid rendering, and renders ok on CPU.

Issue History
Date Modified	Username	Field	Change
2012-05-14 21:15	AGriffiths	New Issue
2012-05-14 21:15	AGriffiths	File Added: LuxIssue1.zip
2012-05-14 21:17	AGriffiths	File Added: LuxIssue2.zip
2012-05-14 22:43	Lord Crc	Assigned To	=> Lord Crc
2012-05-14 22:43	Lord Crc	Status	new => assigned
2012-05-15 15:17	Lord Crc	Note Added: 0003412
2012-05-15 23:27	AGriffiths	Note Added: 0003413
2012-06-23 10:42	AGriffiths	Note Added: 0003440
2012-06-23 10:43	AGriffiths	Note Edited: 0003440	View Revisions
2012-06-27 02:35	Lord Crc	Note Added: 0003441
2012-06-27 02:48	Lord Crc	Note Edited: 0003441	View Revisions
2012-06-27 08:37	AGriffiths	Note Added: 0003442
2012-07-05 02:56	Lord Crc	Note Added: 0003458
2012-07-05 19:44	AGriffiths	Note Added: 0003459
2012-08-21 07:12	jeanphi	Target Version	=> 1.0
2012-09-11 06:07	jeanphi	Target Version	1.0 => 1.1
2012-10-08 00:19	jeanphi	Target Version	1.1 => 1.2
2013-02-25 05:11	jeanphi	Target Version	1.2 => 1.3
2013-05-21 14:31	jeanphi	Assigned To	Lord Crc => jeanphi
2013-05-21 14:33	jeanphi	Note Added: 0003941
2013-05-21 14:33	jeanphi	Status	assigned => feedback

Notes
(0003412) Lord Crc (administrator) 2012-05-15 15:17	From what I can gather, issue 1 is due to numerical issues. It seems some of the vertices are just too close to each other. In at least one case a subdivided vertex, which should be between the two source vertices, actually ends up being located at the exact position of one of the source vertices. This creates a degenerate triangle which the code fails to identify and handle. I haven't looked into issue 2 yet.

(0003413) AGriffiths (reporter) 2012-05-15 23:27	Thanks for the feedback. That makes sense - The SPIKES are set to a value of 0 which morphs them to a position where the are not seen. So by setting the parameter to 0.001 was just enough to avoid that issue. I guess that the rotation/scale of the character must have played a big factor in causing this as well. That would be called Murphy's law. Thanks, Andy

(0003440) AGriffiths (reporter) 2012-06-23 10:42 edited on: 2012-06-23 10:43	Not wishing to be a pain, but has there been any progress on these issues? Lookng forward to trying this scene out with Lux, but need the fixes. Cheers, Andy

(0003441) Lord Crc (administrator) 2012-06-27 02:35 edited on: 2012-06-27 02:48	Unfortunately this is a tricky issue. I managed to change some code so that it handles the numerical precision issues better, however this is just a bandaid fix. I would like to make the code properly handle degenerate edges, so that it will never crash for geometry like yours. I'm still working on that. The fix for issue 1 may or may not solve issue 2, so I will have to wait with the investigation into that until 1 is resolved.

(0003442) AGriffiths (reporter) 2012-06-27 08:37	Much appreciated - thanks for the update. Cheers, Andy

(0003458) Lord Crc (administrator) 2012-07-05 02:56	I think I'll solve issue 1 by detecting the erroneous condition and simply prevent further subdivision. We may later make the code more robust to these conditions, however for now this should prevent the infinite loops. I've not yet figured out exactly how to handle issue 2. I know what the problem is, so hopefully I can figure out something soon.

(0003459) AGriffiths (reporter) 2012-07-05 19:44	Thanks for the update - much appreciated.

(0003941) jeanphi (administrator) 2013-05-21 14:33	Issue 1 should now be fixed (I can render the scene here in GPU mode. Issue 2 seems to be fixed too, Lux now aborts with a nice error message when doing hybrid rendering, and renders ok on CPU.

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