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Differential D8762

Make rigidbody simulation handle animated objects gracefully
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Authored by Sebastian Parborg (zeddb) on Aug 31 2020, 5:06 PM.

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Reviewers
Brecht Van Lommel (brecht)
Jacques Lucke (JacquesLucke)
Commits
rB1aa54d4921c2: Make rigidbody simulation handle animated objects gracefully
Summary

The animated objects was not updated for each internal substep for the rigidbody sim.

This would lead to unstable simulations or very annoying clipping artifacts.

I've updated the code to use explicit substeps and tie it to the scene frame rate.
(This is how it is done in the cloth sim for example)

We would also have issues with the simulated objects becoming "magnetic" and sticking together with other general simulation stability issues.

This was solved by updating the bullet library to the latest version and switching to double precision.

I've created pull a pull request for the custom bullet code that we had. So hopefully we can soon build blender with a upstream release.
https://github.com/bulletphysics/bullet3/pull/3018

This fixes: https://developer.blender.org/T47402

Diff Detail

Event Timeline

Sebastian Parborg (zeddb) requested review of this revision.Aug 31 2020, 5:06 PM
Sebastian Parborg (zeddb) created this revision.
Brecht Van Lommel (brecht) added a comment.Aug 31 2020, 5:14 PM

Please make separate code reviews for the Bullet upgrade and Blender changes.

Jacques Lucke (JacquesLucke) added inline comments.Aug 31 2020, 5:18 PM
release/scripts/startup/bl_ui/properties_scene.py
388–389

This API change should be mentioned in the commit and release notes.

source/blender/blenkernel/intern/rigidbody.c
2217–2218

probably outdated comment

source/blender/blenloader/intern/versioning_290.c
532

Why not use /=?

source/blender/bmesh/operators/bmo_hull.c
31

Should the folder be in the include dirs?

Sebastian Parborg (zeddb) edited the summary of this revision. (Show Details)Aug 31 2020, 5:27 PM
Sebastian Parborg (zeddb) updated this revision to Diff 28336.Aug 31 2020, 5:53 PM

Removed bullet upgrade.

Sebastian Parborg (zeddb) updated this revision to Diff 28337.Aug 31 2020, 5:54 PM
Silas Opel (Schamph) awarded a token.Aug 31 2020, 5:59 PM
Sebastian Parborg (zeddb) updated this revision to Diff 28338.Aug 31 2020, 6:07 PM
Sebastian Parborg (zeddb) marked 2 inline comments as done.
Sebastian Parborg (zeddb) updated this revision to Diff 28339.Aug 31 2020, 6:10 PM
Sebastian Parborg (zeddb) updated this revision to Diff 28341.Aug 31 2020, 6:21 PM
Sebastian Parborg (zeddb) marked an inline comment as done.
Sebastian Parborg (zeddb) added inline comments.Aug 31 2020, 6:26 PM
release/scripts/startup/bl_ui/properties_scene.py
388–389

Right, I'll should only do that after this patch has been accepted though?

Sebastian Parborg (zeddb) updated this revision to Diff 28344.Aug 31 2020, 7:17 PM
Sebastian Parborg (zeddb) updated this revision to Diff 28394.Sep 1 2020, 10:55 AM
Sebastian Parborg (zeddb) updated this revision to Diff 28401.Sep 1 2020, 12:06 PM
David Vogel (Dadido3) awarded a token.Sep 1 2020, 1:07 PM
Jacques Lucke (JacquesLucke) accepted this revision.Sep 1 2020, 2:57 PM
Jacques Lucke (JacquesLucke) added inline comments.
source/blender/blenkernel/intern/rigidbody.c
1936

LISTBASE_FOREACH

1938

snake case

2220

const

This revision is now accepted and ready to land.Sep 1 2020, 2:57 PM
Brecht Van Lommel (brecht) added inline comments.Sep 1 2020, 3:06 PM
source/blender/blenkernel/intern/rigidbody.c
1887–1890

Is there a reason scale is not interpolated for substeps, while position and rotation are?

Sebastian Parborg (zeddb) updated this revision to Diff 28413.Sep 1 2020, 4:27 PM
Sebastian Parborg (zeddb) marked 3 inline comments as done.
Sebastian Parborg (zeddb) updated this revision to Diff 28420.Sep 1 2020, 6:35 PM
Sebastian Parborg (zeddb) marked an inline comment as done.

Now also taking into account scale changes with additional checks to avoid recalculating collision shapes when scale doesn't change.

Sebastian Parborg (zeddb) updated this revision to Diff 28424.Sep 1 2020, 7:19 PM

Updated the scale changed check to be a bit fuzzy so that we don't update the scale because of floating point precision issues.

Sebastian Parborg (zeddb) added inline comments.Sep 1 2020, 10:30 PM
source/blender/blenkernel/intern/rigidbody.c
1682–1684

Reminder: Only do this check at this point for non kinematic objects!

Sebastian Parborg (zeddb) updated this revision to Diff 28437.Sep 2 2020, 12:24 PM
Brecht Van Lommel (brecht) added inline comments.Sep 2 2020, 12:38 PM
source/blender/blenlib/intern/math_vector_inline.c
1378 ↗(On Diff #28437)

Don't use an assert, make the code work for zero size:

for (int i = 0; i < 3; i++) {
  if (v2[i] == 0.0f) {
    if (v1[i] != v2[i]) {
      return false;
    }
  }
  else {
    if (fabsf(v1[i] / v2[i] - 1.0f) > limit) {
      return false;
    }
  }
}
Sebastian Parborg (zeddb) updated this revision to Diff 28438.Sep 2 2020, 12:55 PM
Sebastian Parborg (zeddb) marked an inline comment as done.
Brecht Van Lommel (brecht) accepted this revision.Sep 2 2020, 2:12 PM
Closed by commit rB1aa54d4921c2: Make rigidbody simulation handle animated objects gracefully (authored by Sebastian Parborg (zeddb)). · Explain WhySep 2 2020, 2:21 PM
This revision was automatically updated to reflect the committed changes.
Sebastian Parborg (zeddb) added a commit: rB1aa54d4921c2: Make rigidbody simulation handle animated objects gracefully.

Revision Contents
Changeset List

PathSize
extern/
bullet2/
13 lines
intern/
rigidbody/
4 lines
6 lines
43 lines
10 lines
83 lines
release/
scripts/
startup/
bl_ui/
4 lines
source/
blender/
blenkernel/
8 lines
intern/
163 lines
blenloader/
intern/
18 lines
bmesh/
5 lines
operators/
2 lines
makesdna/
4 lines
intern/
1 line
makesrna/
intern/
12 lines
modifiers/
8 lines

Diff 28420

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extern/bullet2/CMakeLists.txt

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intern/rigidbody/CMakeLists.txt

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intern/rigidbody/RBI_api.h

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intern/rigidbody/RBI_hull_api.h

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intern/rigidbody/rb_bullet_api.cpp

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intern/rigidbody/rb_convex_hull_api.cpp

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release/scripts/startup/bl_ui/properties_scene.py

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source/blender/blenkernel/CMakeLists.txt

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source/blender/blenkernel/intern/rigidbody.c

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source/blender/blenloader/intern/versioning_290.c

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source/blender/bmesh/CMakeLists.txt

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source/blender/bmesh/operators/bmo_hull.c

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source/blender/makesdna/DNA_rigidbody_types.h

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source/blender/makesdna/intern/dna_rename_defs.h

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source/blender/makesrna/intern/rna_rigidbody.c

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source/blender/modifiers/CMakeLists.txt

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