Transformed parents of Rigid Bodies cause problems with Bake To Keyframes #39886

New Issue

ben u · 2014-04-24T23:03:07+02:00

ben u commented

2014-04-24 23:03:07 +02:00

System Information
OS X 10.8.3
NVIDIA GeForce GTX 680MX 2048 MB

Blender Version
Broken: 2.70a Official Blender Foundation release

Short description of error
When a PARENT of Active Rigid bodies has been transformed, Bake Keyframes doesn't recognize these transforms in the children, though the real-time Cache and standard Bake methods do.

Exact steps for others to reproduce the error
In attached .blend file, play back the physics sim. Note the Suzannes fall in the box like they should.
Select the Suzannes and BAKE TO KEYFRAMES (ff 0-100). After Baking, the Suzannes fall in the wrong place.

WHAT I THINK IS GOING ON: The Suzannes are CHILDREN of the cube. The Cube has been moved from [0,0,0] to [5,5,0], and rotated from [0,0,0] to [0d,0d,90d]. This displacement seems to be magnified by the Bake to Keyframes. Scaling the parent creates even stranger results.

Applying the transformation / rotation / scale, or unparenting the Rigid Bodies removes this problem when Baking to Keyframes. However, for complicated sims, parenting is a useful technique for setting things up, and at any rate the Bake should match the Bake to Keyframes.

bakeKeyframes1.blend

**System Information** OS X 10.8.3 NVIDIA GeForce GTX 680MX 2048 MB **Blender Version** Broken: 2.70a Official Blender Foundation release **Short description of error** When a PARENT of Active Rigid bodies has been transformed, Bake Keyframes doesn't recognize these transforms in the children, though the real-time Cache and standard Bake methods do. **Exact steps for others to reproduce the error** In attached .blend file, play back the physics sim. Note the Suzannes fall in the box like they should. Select the Suzannes and BAKE TO KEYFRAMES (ff 0-100). After Baking, the Suzannes fall in the wrong place. WHAT I THINK IS GOING ON: The Suzannes are CHILDREN of the cube. The Cube has been moved from [0,0,0] to [5,5,0], and rotated from [0,0,0] to [0d,0d,90d]. This displacement seems to be magnified by the Bake to Keyframes. Scaling the parent creates even stranger results. Applying the transformation / rotation / scale, or unparenting the Rigid Bodies removes this problem when Baking to Keyframes. However, for complicated sims, parenting is a useful technique for setting things up, and at any rate the Bake should match the Bake to Keyframes. [bakeKeyframes1.blend](https://archive.blender.org/developer/F85858/bakeKeyframes1.blend)

ben u commented

2014-04-24 23:03:07 +02:00

Changed status to: 'Open'

ben u commented

2014-04-24 23:03:07 +02:00

Added subscriber: @BenU

Thomas Beck commented

2014-04-24 23:35:10 +02:00

Added subscribers: @sreich, @plasmasolutions

Thomas Beck commented

2014-04-24 23:35:10 +02:00

@sreich I think this is something for you ... As I see it, the RBs are rotated because the rotation of the cube is not applied previously...but I wonder if that is intentionally. The results of "baking" and "bake to keyframes" should be always the same I would assume - even if you didn't apply the rotation on the parent, right?!
@BenU Apply the rotation on the cubical object - all will be good then.

Greetings, Thomas

@sreich I think this is something for you ... As I see it, the RBs are rotated because the rotation of the cube is not applied previously...but I wonder if that is intentionally. The results of "baking" and "bake to keyframes" should be always the same I would assume - even if you didn't apply the rotation on the parent, right?! @BenU Apply the rotation on the cubical object - all will be good then. Greetings, Thomas

Sergej Reich was assigned by Thomas Beck

2014-04-24 23:35:42 +02:00

Thomas Beck commented

2014-04-24 23:35:42 +02:00

Removed subscriber: @sreich