arb name rot fb
This command allows one to create an arb8 with the desired rotation and fallback angles. In this case, an arb8 with the name of "name" will be created with the desired rotation angle of "rot" degrees and the fallback angle of "fb" degrees.
Examples:
arb top1.s 0 90
arb sidelt.s 90 0
arb upglacis.s 0 60