O-X-Y Type Attachment Modes

Here we provide more detailed information on the use of Align O-X-Y type modes in the Part Attachment editor.

These modes are:
 * Align O-Z-X
 * Align O-Z-Y
 * Align O-X-Y
 * Align O-X-Z
 * Align O-Y-Z
 * Align O-Y-X

These modes are used to attach to a specified vertex, with an orientation determined by reference to other vertices or edges.

must be a vertex. The origin is mapped to this selected point.

Note: If an edge is selected for, O-X-Y type modes are not offered.

and must be either vertices or edges. They provide direction information. For a vertex, the direction is from the origin to the selected vertex. For an edge, it is the direction of the edge. is optional.

Take mode O-X-Z as an example:
 * The O represents the origin, corresponding to.
 * The X indicates that the X-axis of the attached object is to be aligned with the direction of.
 * The Z indicates that the Z-axis of the attached object is to be aligned with the component of the direction of at right angles to the X-axis.
 * The Y-axis completes the orthogonal right-hand axis triad.

For other modes, the axes are mapped in a corresponding fashion.

If is not provided, FreeCAD makes default choices for it.