The picture above was made with this demo POV file and this pen object POV file . ... The cap and pen are separate objects; put together in their default orientation, the pen is "closed". ... The "clip" of the cap is rounded on the inside, and tapers to a point, and also tapers away from the pen, just like the real object. ... The cap is 0.18 units in diameter, the little ridge is 0.197 units in diameter, and the clip extends up to 0.26 units above the central axis. ...