Mesh Reference Objects
We have added the user the option to create reference planes to be used for reference, so being objects added on the mesh, they are not mesh data, so they will not be rendered (at this moment, at least!)
Mesh references can be used to restrict user input in the plane, and can be set as snap target.
The plane is defined by (3+1) points in a plane. This points cannot be selected individually.
Creation is as usual in blender if nothing is selected. If 3 or more vertices are selected they are used in select order, so the first two defines the X vector of the plane, and third one the Y side.This mainly affects to custom transform orientations created from plane.
Changes on source are isolated via WITH_MECHANICAL_MESH_REFERENCE_OBJECTS compiler definition. also
WITH_MECHANICAL_SNAP_TO_PLANE the changes included to allow snapping on them.
Changes are similar to the ones introduced by dimensions.