cPoc fyi...

Just to note, and clarify, the closest point on curve script and node i mentioned is different from the one you'll find under create deformers - point on curve.

That particular point on curve deformer uses the curvePointConstraint command, which is basically constraining cvs (or partial cvs) to a locator.

My script/node will do the opposite - a locator/transform can be constrained to the curve, so if you have the curve skinned/deforming/moving, you can have something stick to the curve. again, its the same as the closestPointOnSurface node, but it works on curves.

anyway, just wanted to clarify since a couple people asked :)

Closest Point on Curve (script)

Here's a python script i wrote recently... closestPointOnCurve. as i previously posted, maya doesn't have a built in node for getting this info, so i wrote my own. this code below is just the *script* version; i'll post the plugin node version another time.

you would call this with a location (world space point) and a curve object. for example:

import jc_closestPointOnCurve as cpoc
cpoc.jc_closestPointOnCurve([0, 0, 0], "curve1")

what you would get returned is the parameterU along the curve, and then the worldspace position of that point along the curve.

import maya.OpenMaya as om
import maya.cmds as mc

# input curve
# input point
# output param
# output point

def jc_closestPointOnCurve(location, curveObject):
        
  curve = curveObject
        
        # put curve into the MObject
  tempList = om.MSelectionList()
  tempList.add(curve)
  curveObj = om.MObject()
  tempList.getDependNode(0, curveObj)  # puts the 0 index of tempList's depend node into curveObj
        
        # get the dagpath of the object
  dagpath = om.MDagPath()
  tempList.getDagPath(0, dagpath)
        
        # define the curve object as type MFnNurbsCurve
  curveMF = om.MFnNurbsCurve(dagpath)
        
        # what's the input point (in world)
  point = om.MPoint( location[0], location[1], location[2])
        
        # define the parameter as a double * (pointer)
  prm = om.MScriptUtil()
  pointer = prm.asDoublePtr()
  om.MScriptUtil.setDouble (pointer, 0.0)
        
  # set tolerance
  tolerance = .00000001
        
  # set the object space
  space = om.MSpace.kObject
        
  # result will be the worldspace point
  result = om.MPoint()
  result = curveMF.closestPoint (point, pointer,  0.0, space)
        
  position = [(result.x), (result.y), (result.z)]
  curvePoint = om.MPoint ((result.x), (result.y), (result.z))
        
  # creates a locator at the position
  mc.spaceLocator (p=(position[0], position[1], position[2]))
        
  parameter = om.MScriptUtil.getDouble (pointer)
        
  # just return - parameter, then world space coord.
  return [parameter, (result.x), (result.y), (result.z)]

feel free to email me any questions :)