A SketchPlane3d represents a 2D planar coordinate system in 3D space, and is
defined by its origin point and X and Y directions (which are always
perpendicular to each other). Sketch planes are the primary tool for converting
back and forth between 2D and 3D coordinates:
This allows you to create algorithms that project from 3D into 2D, perform some calculations in 2D, then convert the result back to 3D.
Many 3D data types have projectInto functions that return the corresponding 2D
data type, and on functions for converting back to 3D. For example,
Triangle3d.projectInto returns a Triangle2d and
Triangle3d.on returns a Triangle3d.
These predefined sketch planes all have the global origin point as their origin point, and use the two indicated global axes as their X and Y axes.
Sketch planes can also be constructed from Frame3d values using
Frame3d.xySketchPlane etc.