[求助]：请教高手（关于面域质量特性）

yjtdkj

小弟想编一个查对象惯性矩的程序，思路是：先把选择的对象做成面域，再求到它的质心，然后以质心为基点MOVE到0，0，0上，再利用CAD中的“面域质量特性”的命令返回惯性矩。不知道是否可行？

eachy

Gets the moment of inertia for the solid.

See Also | Example

Signature

object.MomentOfInertia

object

3DSolid, Region
The object or objects this property applies to.

MomentOfInertia

Variant (three-element array of doubles); read-only
A 3D coordinate based on the current coordinate system.

Remarks

The moment of inertia is returned as X, Y, and Z coordinates defined as a variant.

xyp1964

[php]
;;;惯性矩
(defun c:test043 (/ e bt1 bt g1 g2 g3)
  (setq e (car (entsel)))
  (if (or (= (dxf 0 (entget e)) "3DSOLID")
          (= (dxf 0 (entget e)) "REGION")
      )
    (progn
      (setq bt1        (vla-get-MomentOfInertia
                  (vlax-ename->vla-object e)
                )
            bt        (vlax-variant-value bt1)
            g1        (RTOS (vlax-safearray-get-element bt 0))
            g2        (RTOS (vlax-safearray-get-element bt 1))

      )
      (if (= (dxf 0 (entget e)) "REGION")
        (progn
          (princ "\n")
          (princ (STRCAT "惯性矩: " g1 "," g2))
        )
        (progn
          (setq g3 (RTOS (vlax-safearray-get-element bt 2)))
          (princ "\n")
          (princ (STRCAT "惯性矩: " g1 "," g2 "," g3))
        )
      )
    )
  )
  (princ)
)
(defun dxf (code elist) (cdr (assoc code elist)))
[/php]