Sensor always collides with vehicle

[turanszkij]

Hi, I am trying to put a ragdoll into sensor mode to disable collisions and put in inside a vehicle's rigidbody. The problem is that the ragdoll still collides with the vehicle, and I couldn't find a way to disable it. I am using body.SetIsSensor(true) on every part of the ragdoll and it succeeds, the ragdoll can move through other physics objects, but it still collides with the vehicle, why could this be?

This GIF shows part of the problem, where kinematic ragdoll is forced inside the car from the game code, but the physics objects are pushed outside:

(Note the color of ragdoll is yellow, meaning that right now it's in sensor mode)

In my other test, other ragdolls that I want to go through with the car are stopping the car in its track instead of moving through them.

[jrouwe]

The problem is that the ragdoll still collides with the vehicle, and I couldn't find a way to disable it. I am using body.SetIsSensor(true) on every part of the ragdoll and it succeeds, the ragdoll can move through other physics objects, but it still collides with the vehicle, why could this be?

I don't see how that could happen. I tried to repro this by adding a ragdoll to the vehicle test in the samples:

VehicleTest.zip

And that seems to do what I would expect it to do:

Jolt.Physics.Samples.2025-04-02.21-47-46.mp4

Personally, I would temporarily change the object layer of the bodies in the ragdoll or temporarily remove the ragdoll from the world completely as it is cheaper than making the ragdoll a sensor. Making the ragdoll a sensor goes through the entire collision detection pipeline.

[turanszkij]

Thanks for the reply! I also tried to change the ragdolls to a different layer that specified that collisions should never happen in the callback. But that was not working either, so I guess there is definitely something off about my implementation or game code.

[turanszkij]

Sorry for this, this has been indeed a problem with my game code, and nothing to do with the physics engine. I also changed the solution to your suggestion, putting the player on to a non-colliding layer instead of using sensor mode.