Search Issue Tracker

Feature Request

Votes

2

Found in

2021.3.47f1

2022.3.54f1

6000.0.31f1

6000.1.0a8

6000.2.0a1

6000.3.0a1

Issue ID

UUM-91016

Regression

No

Physics behavior changes when the accumulation API is used in the recorder

-

How to reproduce:
1. Open the “IN-90529-HDRP6.zip“ project
2. Open the “RecorderBug“ Scene
3. Enter Play Mode
4. Observe the Cubes collapsing in the Game view
5. If the Cubes do not collapse, exit Play Mode, add a Cube above the others, and repeat steps 3-5
6. Open the Window > General > Recorder > Recorder Window
7. Check the Accumulator checkbox and set the Sample count to 6 in the Recorder Window
8. Start recording for 300 frames (to ensure there is a reproduction)
9. Observe the recording

Reproducible in: 3.0.4 (2021.3.47f1), 4.0.3 (2022.3.54f1), 5.1.1 (6000.0.31f1, 6000.1.0a8)

Reproduced on: Windows 11 Pro (23H2)
Not reproduced on: No other environment tested

Notes:
- The number of Cubes and Sample count could vary based on the power of the machine it is reproduced on
- If in the recording the Cubes collapse the Sample count should be increased

  1. Resolution Note:

    This is a valid concern from our users, but the reduction of the fixed timestep used in Physics computations was part of the original API design, in order to make rigid bodies produce physically accurate motion blur.

    Changing the implementation to use interpolation might break some applications that were relying on the more accurate physics simulation that that results from using a smaller timestep, so in order to avoid that, we would have to implement this by introducing a new option in the API. This still requires some non-trivial changes, so I'm marking this as a "feature request" and not a bug.

Add comment

Log in to post comment

All about bugs

View bugs we have successfully reproduced, and vote for the bugs you want to see fixed most urgently.