How to change the CollisionFilter at Runtime

Unity Engine
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1

I want my character to collide with A when he is in the air but not when he is on the ground.
So I have looked for a way to change the CollisionFilter during the runtime but could not find it.

How do I change the CollisionFilter at runtime?

2

I was able to solve this problem with the help of this post.

using Unity.Physics;
using Unity.Physics.Systems;
using Unity.Physics.Extensions;

BlobAssetReference<Collider> ColliderBlobReference = physicsCollider.ValueRO.Value.Value.Clone();
CollisionFilter oldFilter = physicsCollider.ValueRO.Value.Value.GetCollisionFilter();
PhysicsCollider newCollider;

ColliderBlobReference.Value.SetCollisionFilter(new CollisionFilter
{
BelongsTo = 0b_0000_0000_0000_0000_0000_0000_0000_0000,
CollidesWith = 0b_0000_0000_0000_0000_0000_0000_0000_0000,
GroupIndex = oldFilter.GroupIndex,
});
newCollider = ColliderBlobReference.AsComponent();
ECB.SetComponent(sortKey, entity, newCollider);

It seems costly to copy the PhysicsCollider, which is a BlobAsset, apply a new CollisionFilter and SetComponent again, but I think I will go with this.

Note that I first tried to turn the Collider on and off by preparing two children and applying a different CollisionFilter to each, and setting the CollisionWorldIndex to a value not used (such as 10) depending on the situation, but this failed.

Thank you very much.

3

It worked!