Maniphest T49324

Displacement > True crash blender in this file
Closed, ResolvedPublic
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Description

System Information
Kubuntu Linux 14.04, GTX 960

Blender Version
Broken: 2.78 from buildbot ( 96f28f9 )

Short description of error
This problem is related to this 'asphalt.blend' test file from this user:
https://blenderartists.org/forum/showthread.php?396697-Cycles-new-microdisplacement-build-and-testing&p=3097111&viewfull=1#post3097111

asphalt.blend521 KB

It seems that 'Ffrima' does not reported yet, so I do the report.
Blender crash when you change Displacement to True

Exact steps for others to reproduce the error
Open 'asphalt.blend' file and change Bump to True in Displacement.

Details

Commits
rC59b8b9a0b8d1: Fix T49324: True displacement crashes when shader returns NaN
rBef8ad66aa2d2: Fix T49324: True displacement crashes when shader returns NaN
Type
Bug

Related Objects

YAFU (YAFU) edited the task description. (Show Details)Sep 11 2016, 5:00 PM
Sergey Sharybin (sergey) triaged this task as "Confirmed" priority.Sep 12 2016, 5:21 PM
Sergey Sharybin (sergey) added subscribers: Mai Lavelle (maiself), Brecht Van Lommel (brecht), Sergey Sharybin (sergey).

Settings used for musgrave texture are quite insane, they are causing some floating point overflows, resulting in really nasty (inf, nan, fltmax) positions for vertices. This confuses BVH builder a lot.

Not sure what would be a real solution here. On the one hand BVH could become more robust perhaps (binning of such a number wouldn't be fun tho) or maybe we should clamp displacement, or maybe we should clamp node settings..

@Brecht Van Lommel (brecht), @Mai Lavelle (maiself) any ideas here?

Mai Lavelle (maiself) added a comment.Sep 12 2016, 7:33 PM

I don't think its good that the node produces such results, but maybe this could be fixed by skipping displacement of vertices when the displacement is inf/nan?

Brecht Van Lommel (brecht) added a comment.Sep 13 2016, 11:59 PM

Definitely reject non-finite displacements. Fixing texture node(s) would be nice too, though I think we have to be robust to such values coming from the node system.