Section View Plane lets you look inside a Blender model to see what is going on. For a single object, select it and hit the Add object section button, then pick a section view color; the section plane is added at the object's origin. Moving or rotating that plane sets the section view, and the Restore Object button deletes the plane and returns the object to its original shape and material or texture.
For all objects at once, the Add scene section button adds a plane at the 3D cursor, and the Restore All button brings the scene back to its original materials and textures. Later versions add a second section plane, placed at a 90-degree angle on the x-axis, for both objects and the scene. Object sections can be set to full or partial and combined with the Inverse Section button, with each sectioned object placed in its own collection. Section planes and views can be recolored, toggled transparent, and hidden or unhidden. A demo video is available.