Collision Shapes - Learning Game Physics with Bullet Physics and OpenGL - page 112

To see this process in action, check out the App_ConvexDecompositionDemo ap-
plication in the Bullet source code.
However, be warned that creating convex hulls from a complex shape (such as a
table or a four-legged chair) requires a lot of CPU cycles to generate accurate colli-
sion responses for them. It is wise to stick with simple collision shapes that estimate
the physical object, such as boxes and spheres, unless absolutely necessary.