How to define a working plane for Sketch?
To define a Working Plane select in the Main Menu New Entity – > Basic – > Working Plane or click the corresponding button in the toolbar. There are several algorithms of working plane creation. Firstly, it is possible to design a Plane, a Planar Face or a Local Coordinate System as a Working Plane. Secondly, a Working Plane can be defined by two vectors. Finally, you can select one of three basic projections of XYZ coordinate system as a Working Plane.