Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate (Z) ...

This file provides functions and modules that construct shapes from a list of cross sections. In the case of skin() you specify each cross sectional shape yourself, and the number of points can vary.

The term "involute" refers to the shape of the teeth: the curves of the teeth are involutes of circles, which are curves that optimize gear performance. Figure 1.1.2: The three marked circles are key ...