I am printing parts for my Tevo Tarantula in purple so that it can have a purple/black theme going on. To that end, I wanted a purple knob. So... I made one. Or rather, I made two. The first version is a straight sided knob with a hollow interior like the original knob, with a slight indent on top. The second version is tapered, like the original, but is filled in instead, with a flat top.

On the second version, I still had the wall thickness set to 0.5mm (from the first version) so you can see a ring around the knob where the hollow portion and the solid portions meet. Thicker walls should prevent that, but I like the way it looks - kind of like a top hat - so.... it stays.