What is the right approach for slicing a 3D mesh? The mesh are all closed surfaces and the slices need to be binary images of what\'s inside the mesh. So for example, a mesh rep
I assume you are talking about triangle meshes?
What's the "right" approach strongly depends on the specifics of your use case.
The OpenGL approach suggested by Jerry might work for you.
Another approach would be to explicitly compute the cuts. You could to this with CGAL. More specifically with its 3D kernel. It features a function that can compute intersections between all sorts of primitives, including a plane and a triangle. Using this function you can accurately compute your intersection outline and render it into an image. - This way you would not depend on OpenGL but on CGAL instead.