Unity Issue Tracker - Sweep-based CCD behaviour changed for some fast-moving objects (ccd threshold minimization)

Won't Fix

2023.3.X

2023.3.0a2 onwards

2023.2.X

2023.2.0b1 onwards

2022.3.X

2022.3.8f1 onwards

2021.3.X

2021.3.30f1 onwards

Not a bug, we improved ccd so that the fast small objects would have less chance of penetrating obstacles.

In this particular case, a change in physics made it so that some behaviours need re-tweaking but the change is a legit improvement and we believe that now simulation matches theoretical results much closer and the players will appreciate that too. We were considering to introduce an optional switch here indeed, but in the end decided not to. Thank you for your understanding, and sorry for the caused troubles.

Not a bug, we improved ccd so that the fast small objects would have less chance of penetrating obstacles.

How to reproduce:
1. Open the “Repro” project
2. Open the “SampleScene”
3. Enter the Play Mode
4. Observe the Console

Expected result: The Console shows consistent results of max height being 16.93414
Actual result: The max height results are dependent on versions

Reproducible in: 2021.3.30f1, 2021.3.33f1, 2022.3.8f1, 2022.3.15f1, 2023.2.4f1, 2023.3.0a18
Not reproducible in: 2021.3.29f1, 2022.3.7f1

Reproduced on: Windows 10
Not reproduced on: No other environments tested

Note:

The max height is 16.44284 in 2021.3.X and 2022.3.X reproducible versions
2023.X.X presents different results than expected but not the same as in the 2022.3.33f1 and 2022.3.15f1 version
The differences in the applied velocity might be related to the fixes done in this issue: https://issuetracker.unity3d.com/issues/objects-are-not-colliding-when-time-dot-fixeddeltatime-is-smaller-or-equal-to-5-ms

Sweep-based CCD behaviour changed for some fast-moving objects (ccd threshold minimization)

Unity: PhysX

Won't Fix

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Sweep-based CCD behaviour changed for some fast-moving objects (ccd threshold minimization)

Unity: PhysX

Statuses

Won't Fix

Resolution Notes

2023.3.XWon't FixNot a bug, we improved ccd so that the fast small objects would have less chance of penetrating obstacles.

2023.2.XWon't FixNot a bug, we improved ccd so that the fast small objects would have less chance of penetrating obstacles.

2021.3.XWon't FixNot a bug, we improved ccd so that the fast small objects would have less chance of penetrating obstacles.

Description

Prioritise and Follow this issue

Have a workaround or additional info about this issue?