一.
CEX, CEY, CEZ :The centroid of the input
centroid(surface_node, type):
The centroid is the center of the bounding box of the points, not the average position of the points.
在获取当前对象中心点时,centroid和$CEXYZ是相等的
二.
CTRL+SHIFT+CLICK 撤销参数中的表达式,并获取表达式当前值赋予参数