If you are using a ruler and compass to draw something - for example, a perpendicular bisector of a line or bisecting an angle - make sure you clearly show the compass arcs in your construction.

Three simple end treatments are supported, "flat" (the default), "round" and "pointed". The "flat" treatment cuts off the ends perpendicular to the path and the "round" treatment applies a semicircle ...

In the former case, the principal axis is always perpendicular to the base plane, while in the latter, the principal axis either aligns with the bisector of the bonds or is close to perpendicular to ...