title: To what part of the object should the origin correspond in object space?
body: <p>When defining an object's vertices, I'm unsure if the origin (of the object space) should correspond to the middle of the object or some other part of the object like the top/bottom left corner. It seems to me that the middle would make rotations easier, while a top/bottom left corner origin would make positioning easier. I'm wondering what the convention is in the OpenGL world.</p>