Bullet Physics question:
**Can you use the grouping tool to help you select which vertices to constrain in the Bullet physics simulations. You CAN do this in the Cloth room to add constraints to areas of a cloth object. So if you want to constrain a button to a shirt you can find the button material on the shirt using the grouping tool and add that button to the rigid constraint group of a cloth object. Like the Cloth Room the Bullet Physics controls will allow you to add a rigid constraint to a cloth object, but you would do this by painting the vertices. Can you just add the material that those vertices are assigned to to the rigid constraint group using the grouping tool?
I do not think so. At least I haven't been able to. Like you said painting is the only way I have found.