Question How to access material properties of a Collider?

Hi,

I want to access the friction of a rigidbody that I got through a raycast.
This is the code I came up with. I get a pointer to the collider and can then access the friction by casting the pointer to a sphere collider pointer. This works fine if for example the hitBody is a quad collider (plane) but not for a mesh collider. I'm guessing this is because the mesh collider does not have a material property. How should I modify the code to be able to access the friction of any collider?

Thanks!

Code (CSharp):

1. RigidBody hitBody = collisionWorld.Bodies[hit.RigidBodyIndex];
2.  
3. unsafe
4. {
5.     var ptr = (SphereCollider*)hitBody.Collider.GetUnsafePtr();
6.     Debug.Log(ptr->Material.Friction);
7. }

 

You can check that a Collider has the CollisionType of Convex then cast to a ConvexColliderHeader e.g.

Code (CSharp):

1.        
2.         var collider = collisionWorld.Bodies[hit.RigidBodyIndex].Collider;
3.         if (collider.Value.CollisionType == CollisionType.Convex)
4.         {
5.             unsafe
6.             {
7.                 var header = (ConvexColliderHeader*)collider.GetUnsafePtr();
8.                 var material = header->Material;
9.                 material.Friction = newFriction;
10.                 header->Material = material;
11.             }
12.         }
13.  

We are looking into make Materials available for composite colliders, as well making this sort of Material tweaking much easier without the need for unsafe blocks.

 

Also, you can get a leaf collider by using the hit.ColliderKey and then you'll know for sure that the leaf collider is convex. Check CharacterControlerUtilities.cs, method is called IsTrigger().

 

Thank you both,

It's nice to hear that you are working to improve this. For now I managed to make it work by accessing the leaf collider as mentioned.

Code (CSharp):

1. public static Material GetMaterial(RigidBody rigidBody, ColliderKey colliderKey)
2. {
3.     Material material;
4.     unsafe
5.     {
6.         Collider* colliderPointer = (Collider*)rigidBody.Collider.GetUnsafePtr();
7.         ChildCollider childCollider;
8.         colliderPointer->GetLeaf(colliderKey, out childCollider);
9.         ConvexCollider* childColliderPointer = (ConvexCollider*)childCollider.Collider;
10.         material = childColliderPointer->Material;
11.     }
12.     return material;
13. }