居中布置喷头

平面消防里有很多喷头布置方式，对一般布置喷头也非常方便。但在无吊顶场合需考虑主梁、次梁位置的时候，喷头一般根据梁线布置在中间位置，此时布置喷头就有点不方便了。下面有段程序，希望对大家有用：
;;;用之前需要已经布置至少一个喷头
;;;已经有了结构梁线
(defun c:tg (/ basePT basepto basepoint firpoint secpoint midx midy)
(princ "\n居中布置天正喷头：")
(setq
basePT (ssname
(ssget "x"
'((0 . "TCH_EQUIPMENT") (2 . "$TwtSys$00000125"))
)
0
)
)
(setq basepto (vlax-ename->vla-object basept))
(setq basepoint (vlax-3d-point (cdr (assoc 10 (entget basept)))))
(while (and (setq firpoint (getpoint "\n点选长方形两个角点，第一点："))
(setq secpoint (getpoint firpoint "第二点："))
)
(setq midx (/ (+ (car firpoint) (car secpoint)) 2.0))
(setq midy (/ (+ (cadr firpoint) (cadr secpoint)) 2.0))
(setq PTcopy (vla-copy basepto))
(vla-move ptcopy basepoint (vlax-3d-point (list midx midy)))
)
(princ)
)