选择最长和最短的曲线

Question

我正在尝试创建一个将选择一堆NURBS曲线的脚本，并测量这些曲线的长度。
因此，理想情况下，我可以选择最短的曲线，而较长的曲线则未选择（或相反）。到目前为止，我都有：

import maya
import string
    for i in maya.cmds.ls(selection=True):
        shapeNodes = maya.cmds.listRelatives(i,shapes=True)
        for shape in shapeNodes:
            if maya.cmds.nodeType(shape) == "nurbsCurve":
                print "Curve: %s is %s units long" % (shape, maya.cmds.arclen(shape,))
                cvs = mc.getAttr(string.join(shapeNodes) + '.spans')+1
                print "The: %s  has %s cvs" % (shape,cvs)
            else:
                print "Wrong: %s is a %s" % (shape, maya.cmds.nodeType(shape))

Answer 1

您可以在列表理解的情况下摆脱循环。将所有形状及其长度收集到（长度，形状）对的列表中，然后排序 - 这给您最短的曲线：

import maya.cmds as cmds
sel = cmds.ls(sl=True)
shapeNodes = cmds.listRelatives(sel,shapes=True)
shapeNodes = cmds.ls(shapeNodes, type= 'nurbsCurve', l=True)  # long paths to avoid confusion
selectable = [ ( cmds.arclen(item), item)  for item in shapeNodes]
if selectable:
   selectable.sort()
   cmds.select( selectable[0][-1])
else:
   cmds.select(cl = True)

您也可以将其放入函数中，然后返回selectable列表以在其他地方处理。

Answer 2

我建议出于简单和轻松的明显原因开始使用pymel

import pymel.core as pm
curveInfo = pm.createNode('curveInfo')
for thisCurve in pm.ls(sl=True):
    #get the shape node
    thisShape = thisCurve.getShape()
    #connect the world space to the curve info
    thisShape.worldSpace >> curveInfo.inputCurve
    #this is how you get the value
    print curveInfo.arcLength.get()
    #from here you can put the value in whatever you need
#delete the curve info
pm.delete(curveInfo)