Smooth normals from contact collision points

Unity Engine
1

Hi there,

Just wondering if there’s a way to get the actual smooth surface normal from a collision contact point?
The only way I can think of to do this is to raycast back out to the collision mesh and use the data from the hit to get the normals based off the barycentric coordinate of the hit.

It feels like double handling though and a potentially error prone way to go about it, but the contact points seems to give me very little to work with.

Any help would be great!
Thanks,
Pete

2

I think it is… I don’t think those vertex normals are “processed” anywhere except in the shader.

But I don’t think you’ll get vertex info off the texture, unless you bake it in there…

3

The vertex normal data is stored in the mesh, if you iterate through the points you can access it all. But, yeah I think raycasting back is an okay way to go. If I use Collider.Raycast and feed in the collider geo from the collision point. Just thought I might be missing out on an easier way.

4

If you have two cubes hitting each other at an angle, what is the normal of the collision?

5

Well you can get a bunch of data back from the collision contacts. Really I just want to get mesh data from the point on a mesh that the contact has occurred. You get the both meshes from the collision.contacts data and can easily use that to build a raycast. Just felt like it might be a little crude a method, but it seems fine.