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 :)

Python - cPoC

So what is *up* with maya not including a proc or node that gives you the closest point on a curve (from a given point)? You get a node that will give you the closestPointOnSurface... and a node that will give you the closestPointOnMesh... so why leave curves out?

It makes no sense... they even give you an example .cpp plugin source to create that node yourself! crazy, huh?

well, i needed to get the info of a closestPointOnCurve in one of my rig scripts, so tossing out the idea of requiring plugins (i try to do as much as i can without them... mostly), i opted to just write something quickly for this. i'll mess with making it into a node/python plug later, but for now i just wanted to get that info and use it.

if anyone is interested in the script, gimme a shout. i'll toss it on highend3d sooner or later, when i have a moment.

OR, maybe i can train myself to blog more and actually post it with a description later... :)