Soft body physics much slower in 2.69 compared to 2.68a #37686

New Issue

Joshua Dolan · 2013-12-03T06:33:15+01:00

Joshua Dolan commented

2013-12-03 06:33:15 +01:00

Mac OS X 10.9.0
MacBook Pro (2011) 2.2 GHz Intel Core i7 16 GB 1333 MHz DDR3
AMD Radeon HD 6750M 1024 MB

Blender Version
Broken: Blender 2.69.0 r606991
Worked: Blender 2.68.0 r58536

Short description of error
Soft body objects in 2.69 slow down considerably when collisions start happening compared to 2.68a. CPU usage is not noticeably impacted in 2.68a at the most "intense" part of the running scene, showing 5% peak in the "Physics" debug output where in 2.69 the same scene peaks at 90%+.

Enabling cluster collisions seems to help speed up the calculations in 2.69 and keeps the frame rate up but causes many undesirably effects such as the object suddenly "exploding" or flying away from its original position making it difficult / impossible to use reliably.

Exact steps for others to reproduce the error

Set the default cube in a scene to use Rigid Body physics and lock the translation on all three axis.
Add a plane above the cube and in edit mode do several basic subdivisions to add more faces.
Set the plane to use Soft Body physics turning "Shape Match" down to near zero and disabling "Bending Constraints"
Add a "Generic 6 DOF" Rigid Body Joint constraint to the Plane with the Cube as the Target. (Leave the Pivot location - It is only there to keep the Plane from slipping away.)
Run the scene in the BGE in both 2.69 and 2.68a and compare the results.

Soft_body_bug.blend

Mac OS X 10.9.0 MacBook Pro (2011) 2.2 GHz Intel Core i7 16 GB 1333 MHz DDR3 AMD Radeon HD 6750M 1024 MB **Blender Version** Broken: Blender 2.69.0 r606991 Worked: Blender 2.68.0 r58536 **Short description of error** Soft body objects in 2.69 slow down considerably when collisions start happening compared to 2.68a. CPU usage is not noticeably impacted in 2.68a at the most "intense" part of the running scene, showing 5% peak in the "Physics" debug output where in 2.69 the same scene peaks at 90%+. Enabling cluster collisions seems to help speed up the calculations in 2.69 and keeps the frame rate up but causes many undesirably effects such as the object suddenly "exploding" or flying away from its original position making it difficult / impossible to use reliably. **Exact steps for others to reproduce the error** 1. Set the default cube in a scene to use Rigid Body physics and lock the translation on all three axis. 2. Add a plane above the cube and in edit mode do several basic subdivisions to add more faces. 3. Set the plane to use Soft Body physics turning "Shape Match" down to near zero and disabling "Bending Constraints" 4. Add a "Generic 6 DOF" Rigid Body Joint constraint to the Plane with the Cube as the Target. (Leave the Pivot location - It is only there to keep the Plane from slipping away.) 5. Run the scene in the BGE in both 2.69 and 2.68a and compare the results. [Soft_body_bug.blend](https://archive.blender.org/developer/F36165/Soft_body_bug.blend)

Joshua Dolan commented

2013-12-03 06:33:15 +01:00

Changed status to: 'Open'

Joshua Dolan commented

2013-12-03 06:33:15 +01:00

Added subscriber: @jdolan

John Roper commented

2013-12-08 21:23:17 +01:00

Added subscriber: @JohnRoper

John Roper commented

2013-12-08 21:24:31 +01:00

I do not know what this is. I have noticed this same problem myself and have been looking into it but can not find the reason. I will keep looking though.