Issue with position based physic solver

Development Asset Creation
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21

Hello [mention removed]​

Thanks for the reply.

Indeed, the previous generation was impulse-based, and Chaos is using PBD.

For the sake of understanding, would it be possible for you to share a minimal project that mimics your setup and displays the behavior you are seeing?

Let me know.

All the best,

[mention removed]​

22

Hello [mention removed]​

Thank you for the repro project.

This is what I’m seeing on Chaos Visual Debugger (CVD):

[Image Removed]Am I right to assume this is the behavior you are referring to?

I’ve also noticed, by inspecting CVD, that the colliding particles don’t have CCD enabled, despite it being enabled in the Editor.

CVD:

[Image Removed]Editor:

[Image Removed]

Enabling this in the Skeletal Mesh Component did not enable it on the physics side.

This makes sense because the actual physics body comes from the Physics Asset, so I’ve gone ahead and changed it on SportsCar_PhysicsAsset:

[Image Removed]

Inspecting CVD, we can confirm CCD is enabled in the particle:

[Image Removed]

Now it looks like the cars were pushed backwards:

[Image Removed]Is this the outcome you expect from such a collision?

Let me know if this is helpful in any way.

All the best,

[mention removed]​

23

Hello [mention removed]​

I’ve been testing here, and the conclusion I’ve drawn is that the collision shape is negatively affecting the result of the collision.

I’ve changed the template PhysicsAsset in a rather extreme fashion and added a Box collider that engulfs the convex shape:

[Image Removed]With this setup, the collisions always resulted in the cars being pushed backwards.

I can only surmise that the convex shape is the culprit here.

What do you think?

Let me know.

All the best,

[mention removed]​