Jaggies in baked physics while using in Sequencer's slow motion. #49841

New Issue

Vladislav Turbanov · 2016-10-25T15:45:48+02:00

2016-10-25 15:45:48 +02:00

Open the file and hit the play button. The baked physics behaves in a weird jagged movement.
cycles-slow-motion-physics-test.blend

Open the file and hit the play button. The baked physics behaves in a weird jagged movement. [cycles-slow-motion-physics-test.blend](https://archive.blender.org/developer/F386179/cycles-slow-motion-physics-test.blend)

Vladislav Turbanov commented

2016-10-25 15:45:48 +02:00

Changed status to: 'Open'

Vladislav Turbanov commented

2016-10-25 15:45:48 +02:00

Added subscriber: @VladislavDmitrievichTurbanov

ronan ducluzeau commented

2016-12-13 15:00:25 +01:00

Added subscriber: @zeauro

ronan ducluzeau commented

2016-12-13 15:00:25 +01:00

In your .blend file, physics scene's frame rate is at 60 fps and Sequencer scene's frame rate is at 24fps.
For rigid bodies, there is no subframe support.
Physics cache step cannot be set below 1 cache step per frame.

It means that there will be a lack of frame/cache step for any slow down below a speed factor of 24/60 = 0.4.
But speed factor of Speed Strip of .blend file is set at 0.1.

Physics speed is not something that can be changed after the bake.
An acceleration is not a problem but a slow down always needs more frames.
Blender will not create subframes for physics at video editing step.

You have to anticipate slow motion and create as many frames as needed at baking time.

Keep same frame rate for both scene.
But use speed setting in Rigid Body World Panel of Scene Properties instead of confusing frame rate changes.

In your .blend file, physics scene's frame rate is at 60 fps and Sequencer scene's frame rate is at 24fps. For rigid bodies, there is no subframe support. Physics cache step cannot be set below 1 cache step per frame. It means that there will be a lack of frame/cache step for any slow down below a speed factor of 24/60 = 0.4. But speed factor of Speed Strip of .blend file is set at 0.1. Physics speed is not something that can be changed after the bake. An acceleration is not a problem but a slow down always needs more frames. Blender will not create subframes for physics at video editing step. You have to anticipate slow motion and create as many frames as needed at baking time. Keep same frame rate for both scene. But use speed setting in Rigid Body World Panel of Scene Properties instead of confusing frame rate changes.

Sergey Sharybin commented

2017-01-25 12:43:17 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2017-01-25 12:43:17 +01:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2017-01-25 12:43:17 +01:00

Sergey Sharybin self-assigned this 2017-01-25 12:43:17 +01:00

Sergey Sharybin commented

2017-01-25 12:43:17 +01:00

This is indeed a subframe interpolation issue.

Surely it'll be good to have support of that, but we are also reconsidering the whole physics integration for 2.8 series and changing the existing behavior now is not really a good time investment. Especially since there is other ways to achieve your needs in this case.

So thanks for the report, but for now it's considered a TODO.

P.S. This issue is also has nothing to do with Cycles.

This is indeed a subframe interpolation issue. Surely it'll be good to have support of that, but we are also reconsidering the whole physics integration for 2.8 series and changing the existing behavior now is not really a good time investment. Especially since there is other ways to achieve your needs in this case. So thanks for the report, but for now it's considered a TODO. P.S. This issue is also has nothing to do with Cycles.

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Jaggies in baked physics while using in Sequencer's slow motion. #49841