Unexpected results when using raycast.GetCollisionFaceIndex with the MeshDataTool

[Petey]

Godot Version

Godot Engine v4.4.1.stable.mono.official

Question

Hi all!,

I’m using raycast.GetCollisionFaceIndex and sending that to the MeshDataTool to get information from the hit. The problem is, I seem to be getting unexpected results. In this example I’ve tried to highlight the points that make up the collided face but it doesn’t always work (as in 2 and 4).

Here is the basic script.

    public override void _PhysicsProcess(double delta)
    {
        base._PhysicsProcess(delta);
        
        // Move raycast point
        float time = Time.GetTicksMsec();
        float offset = Mathf.Sin((time) / (1000) );
        raycast.Position = new Vector3(offset * 4, raycast.Position.Y, 0);
        
        // Update collision data
        if (raycast.IsColliding())
        {
            CollisionObject3D other = (CollisionObject3D)raycast.GetCollider();
            meshInstance3D = other.GetParent().GetNode<MeshInstance3D>("Mesh");
            meshDataTool.CreateFromSurface((ArrayMesh)meshInstance3D.Mesh, 0);
            
            // Highlight points that make up the collision face
            int collisionFaceIndex = raycast.GetCollisionFaceIndex();
            for (var i = 0; i < 3; i++)
            {
                var index = meshDataTool.GetFaceVertex(collisionFaceIndex, i);
                var vertex = meshInstance3D.ToGlobal(meshDataTool.GetVertex(index));
                debugSpheres[i].GlobalPosition = vertex;
            }
        }
    }

I think the problem might be that the collision mesh has a different order to the mesh I’m giving to the meshdata tool but I’m not sure.

Any ideas?
Thanks!
Pete