Cloth jitters in Movie Render Queue renders when temporal sampling is enabled

The Cloth simulation time step smoothing is interfering with the substepping fix for multi Temporal Samples by changing the very variable DeltaTime and causing some large errors in the cloth simulation due to increasing/decreasing convergence.

Simulating with p.ChaosCloth.UseTimeStepSmoothing 0 fixes the issue.

This Cvar needs to be added to the MovieRenderPipeline startup sequence to solve this issue for everyone.

• Enable the Movie Render Queue plugin. Restart the editor.
• Open the ContentExample project in editor.
• Locate the asset ExampleContent/Cloth/Clothspheres_SCOn and place it in the level.
• Click on the clap icon and do Add Level Sequence. Choose a name and save.
• Open the sequence, create a new Camera cut by clicking on the camera icon. Make sure the cloth asset is visible in the camera view.
• Go to menu Window/Cinematics and open the Movie Render Queue.
• Click on the + Render and find/select your sequence.
• Click on Unsaved config to open a new setting window, in the new window click on + Setting button and choose Anti-Aliasing.
• In the Anti-Aliasing settings, use 8 for sample count and tick Override Anti-Aliasing. Click Accept to save the settings.
• Back in the Movie Render Queue window, click on Render (Local).

Actual result: The cloth simulate with weird undulating jitters.  

Expected result: The cloth simulate without jitters.

UE-172069