整理一些 PDMS 常用的命令，方便自己查找。
在3D模型中添加辅助标识
- mark ce
- unmark ce
- unmark all
- pin1 at ce
- pin1 off
- aid text |$!!ce.desc| AT $!!ce.pos
- aid arrow at $!pos dir $!xdir Height $!size
- aid clear all
- enhance ce col 1
遍历选择集
!selection = object SELECTION()
!selection.getCurrent()
!selectionlist = !selection.getSelection()
do !mem values !selectionlist
-- do something
enddo
