Display shows physics object original location during playback, not simulated location. #100601

New Issue

Stephen Imhoff · 2022-08-24T02:39:17+02:00

Stephen Imhoff commented

2022-08-24 02:39:17 +02:00

System Information
Operating system: Ubuntu 22.04.1
Graphics card: Nvidia RTX 2080

Blender Version
Broken: 3.2.2
Worked: unknown

Short description of error

I have a file/simulation where, during playback, physics objects briefly are displayed in their original (non-simulated) location. Manually advancing frames doesn't appear to cause the effect to occur (or occurs to briefly for me to notice). The initial sim that builds the cache doesn't cause it to occur (although that runs about as fast as the playback).
This doesn't appear to affect rendering. The physics simulation itself appears otherwise correct.

Screencast from 08-23-2022 04:53:18 PM.webm

Exact steps for others to reproduce the error
I don't have a "safe" file to share publicly, despite attempts at a repro - these are corporate assets. I can probably share them privately, if necessary. The problem is that the issue appears at least partially resource-dependent, so may not reproduce on other machines anyways....

Both of the meshes in the scene are convex hull rigid bodies, with an additional collision modifier (to interact with softbodies). They have a child body with a geometry node tree.

**System Information** Operating system: Ubuntu 22.04.1 Graphics card: Nvidia RTX 2080 **Blender Version** Broken: 3.2.2 Worked: unknown **Short description of error** I have a file/simulation where, during playback, physics objects *briefly* are displayed in their original (non-simulated) location. Manually advancing frames doesn't appear to cause the effect to occur (or occurs to briefly for me to notice). The initial sim that builds the cache doesn't cause it to occur (although that runs about as fast as the playback). This doesn't appear to affect rendering. The physics simulation itself appears otherwise correct. [Screencast from 08-23-2022 04:53:18 PM.webm](https://archive.blender.org/developer/F13414483/Screencast_from_08-23-2022_04_53_18_PM.webm) **Exact steps for others to reproduce the error** I don't have a "safe" file to share publicly, despite attempts at a repro - these are corporate assets. I can probably share them privately, if necessary. The problem is that the issue appears at least partially resource-dependent, so may not reproduce on other machines anyways.... Both of the meshes in the scene are convex hull rigid bodies, with an additional collision modifier (to interact with softbodies). They have a child body with a geometry node tree.

Stephen Imhoff commented

2022-08-24 02:39:17 +02:00

Added subscriber: @Clockwork-Muse

Pratik Borhade commented

2022-08-25 06:26:29 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-08-25 06:26:29 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Pratik Borhade commented

2022-08-25 06:26:29 +02:00

Thanks for the report. Simple .blend file will help us to investigate this further

Stephen Imhoff commented

2022-08-25 06:28:28 +02:00

Sure, is there a way to privately upload/share the file? I don't want it on the public tracker.

Pratik Borhade commented

2022-08-25 07:21:11 +02:00

Hi, I would suggest to make a simple version of file so that it'll be available publicly and more people can look into the issue.

Stephen Imhoff commented

2022-08-26 00:52:30 +02:00

Also reproduces on:
System Information
Operating system: Windows 11 - Dell XPS 15 9500
Graphics card: Nvidia GeForce GTX 1650 Ti

Blender Version
Broken: 3.2.2
Worked: unknown

Okay, I've managed to remove the original mesh geometry, and as much of the file as I can. If I change anything else the issue stops reproducing.

If I remove the Geometry Node modifier; delete the driver, or give it a valid path; change the "container" input away from the hidden internal bounding box
If I remove the Collision modifier
If I remove carton.001 (the mesh that doesn't display this issue).

There appears to be a dependency cycle due to the use of the collision modifier; however, this doesn't seem to be the sole cause, because as near as I can tell it's intended to have both the collision modifier and rigid body physics on an object, plus the start of this file had multiple objects with both, but only carton.002 showed this behavior...

Dependency cycle detected:
  OBcarton.002/Transform Component/TRANSFORM_FINAL() depends on
  OBcarton.002/Transform Component/TRANSFORM_SIMULATION_INIT() via 'Simulation -> Final Transform'
  OBcarton.002/PointCache Component/POINT_CACHE_RESET() via 'Point Cache -> Rigid Body'
  OBcarton.002/Geometry Component/GEOMETRY_EVAL_INIT() via 'Geometry Init -> Point Cache'
  OBcarton.002/Transform Component/TRANSFORM_FINAL() via 'Collision Modifier'
Dependency cycle detected:
  SCScene/Transform Component/RIGIDBODY_SIM() depends on
  OBcarton.002/Transform Component/TRANSFORM_SIMULATION_INIT() via 'Object Transform -> Rigidbody Sim Eval'
  OBcarton.002/PointCache Component/POINT_CACHE_RESET() via 'Point Cache -> Rigid Body'
  OBcarton.002/Geometry Component/GEOMETRY_EVAL_INIT() via 'Geometry Init -> Point Cache'
  OBcarton.002/Transform Component/TRANSFORM_FINAL() via 'Collision Modifier'
  OBcarton.002/Transform Component/RIGIDBODY_TRANSFORM_COPY() via 'Rigidbody Sync -> Transform Final'
  SCScene/Transform Component/RIGIDBODY_SIM() via 'Rigidbody Sim Eval -> RBO Sync'
Detected 2 dependency cycles

During simplification there were times when manual frame advance did retain the original item location. However, I haven't been able to check whether it would render with the incorrect location.
repro_simplified.blend

Also reproduces on: **System Information** Operating system: Windows 11 - Dell XPS 15 9500 Graphics card: Nvidia GeForce GTX 1650 Ti **Blender Version** Broken: 3.2.2 Worked: unknown Okay, I've managed to remove the original mesh geometry, and as much of the file as I can. If I change anything else the issue stops reproducing. - If I remove the Geometry Node modifier; delete the driver, or give it a valid path; change the "container" input away from the hidden internal bounding box - If I remove the Collision modifier - If I remove `carton.001` (the mesh that doesn't display this issue). There appears to be a dependency cycle due to the use of the collision modifier; however, this doesn't seem to be the sole cause, because as near as I can tell it's intended to have both the collision modifier and rigid body physics on an object, plus the start of this file had multiple objects with both, but only `carton.002` showed this behavior... ``` Dependency cycle detected: OBcarton.002/Transform Component/TRANSFORM_FINAL() depends on OBcarton.002/Transform Component/TRANSFORM_SIMULATION_INIT() via 'Simulation -> Final Transform' OBcarton.002/PointCache Component/POINT_CACHE_RESET() via 'Point Cache -> Rigid Body' OBcarton.002/Geometry Component/GEOMETRY_EVAL_INIT() via 'Geometry Init -> Point Cache' OBcarton.002/Transform Component/TRANSFORM_FINAL() via 'Collision Modifier' Dependency cycle detected: SCScene/Transform Component/RIGIDBODY_SIM() depends on OBcarton.002/Transform Component/TRANSFORM_SIMULATION_INIT() via 'Object Transform -> Rigidbody Sim Eval' OBcarton.002/PointCache Component/POINT_CACHE_RESET() via 'Point Cache -> Rigid Body' OBcarton.002/Geometry Component/GEOMETRY_EVAL_INIT() via 'Geometry Init -> Point Cache' OBcarton.002/Transform Component/TRANSFORM_FINAL() via 'Collision Modifier' OBcarton.002/Transform Component/RIGIDBODY_TRANSFORM_COPY() via 'Rigidbody Sync -> Transform Final' SCScene/Transform Component/RIGIDBODY_SIM() via 'Rigidbody Sim Eval -> RBO Sync' Detected 2 dependency cycles ``` During simplification there were times when manual frame advance did retain the original item location. However, I haven't been able to check whether it would render with the incorrect location. [repro_simplified.blend](https://archive.blender.org/developer/F13417525/repro_simplified.blend)

Pratik Borhade commented

2022-09-02 04:34:41 +02:00

Changed status from 'Needs User Info' to: 'Needs Triage'

Stephen Imhoff commented

2022-09-02 04:40:27 +02:00

Side note - I have now gotten instances where it renders in the initial placed location as well. Note that parented objects may or may not be affected - some with geometry nodes show the nodes where I expect the simulated location to be, but some cases where there are multiple sub-objects have only some of them in the simulated location (and the rest in the initial location).