Physics, Colliders and Custom Mesh

I'm very new to Unity so I hope I'm asking this question correctly...

I'm building a 2D game and want to apply physics to a game object that uses a texture that displays a 6 sided polygon. Basically I have a "stop sign" looking shape in the game. I'm a bit unclear what the best way is to get physics working against this "shape". Right now I'm using a GUITexture, applying a Rigidbody and Mesh Collider. The mesh collider is where I start getting confused. How do I assign the "mesh" property?

In general what is the proper way to go about this? Do I use a GUITexture? Do I dynamically create the mesh in script? Do I model the shape in another tool and import it?

Any insight is greatly appreciated.

If your model was imported from a 3D modeling program, and you apply a MeshCollider, it will automatically assign the mesh to the collider. MeshColliders will only collide with certain types of objects, see the bottom of this page for a table of what collides with what.

If you want your MeshCollider to collide with more types of objects, tick the Convex option. This creates a convex collider around your mesh (though, if your mesh is already convex, this doesn't present a problem), and then it will collide with more types of objects than a standard mesh collider.

And the best way to go about modelling in Unity is to create the model in another program, and then import it into Unity. Unless your stop sign is procedural and MUST be generated via code, it's just a lot easier to do it in some 3D modeling program and then import it. Unity is a great game engine, but it's certainly not a 3D modelling application. ;)