RA

This is similar to CA command, except now you are rotating objects. Select objects, pick a base point. Then type your rotation angle to copy - rotate, or just press enter. You will have a polar array at various spacing. Type "U" to undo previous actions. Type "X" to select exit option.

CA

Select objects, pick a base point and a direction point. Then type your distance to copy, or just enter enter then enter. You will have an array of grid lines, or rebar dots etc. at varies spacings. Type "U" to undo previous actions. Type "X" to select eXit option.

7BRPURLINS

Select purlin lines and enter lapping length. The code will find crossing lines (they can be columns or beams or trusses) and break each purlin at every intersection point, extend each to both sides a distance exactly equal to your specified lapping length.