Many third-party renderers will have some clip plane or a shader that will let you create renders of cross-sections of models. With Arnold, that is the Clip Geo Shader. Check out this quick step-through for working with the shader in Arnold and how Arnold’s rendering specialist Lee Griggs rendered this amazing-looking animation of an android’s head.
The render shows a nice mix of Arnold’s toon shader and the clip shader.
The Clip Geo shader in Arnold allows you to designate a shape that will cut away from other objects at render time based on the intersection.