getClosetVertsToObj.py

from maya.api import OpenMaya
from maya import cmds

def getDistance(x1, y1, z1, x2, y2, z2):
	sq1 = (x1-x2)*(x1-x2)
	sq2 = (y1-y2)*(y1-y2)
	sq3 = (z1-z2)*(z1-z2)
	return math.sqrt(sq1 + sq2 + sq3)


def getClosestVertToObject(obj, surface, distance_max=2):
  	for each in [obj, surface]:
		if not cmds.objExists(each):
				raise Exception('%s does not exists'%each)

	space = OpenMaya.MSpace.kWorld

	## Get Object Position
	mSelect = OpenMaya.MSelectionList()
	mSelect.add(obj)
	obj_dagPath = mSelect.getDagPath(0)
	obj_MFnTransform = OpenMaya.MFnTransform(obj_dagPath)
	obj_MPoint = obj_MFnTransform.rotatePivot(space)
	obj_pos = [round(x, 3) for x in obj_MPoint][:3]


	## Get Surface MFnMesh
	mSelect = OpenMaya.MSelectionList()
	mSelect.add(surface)
	surface_dagPath = mSelect.getDagPath(0)
	surface_MFnMesh = OpenMaya.MFnMesh(surface_dagPath)

	## Get Vertex ids of surface
	vertIds = surface_MFnMesh.getVertices()[1]

	closest_vert_list = []
	for each in vertIds:
		vert_pos = surface_MFnMesh.getPoint(each)
		vert_pos = [round(x, 3) for x in vert_pos][:3]

		## Get distance of objects
		distance = getDistance(*obj_pos+ vert_pos)

		if distance< distance_max:
			  closest_vert_list.append(each)
				  
	vert_list = []
	for ii in closest_vert_list:
		node = surface+ '.vtx[%s]'%(ii)
		vert_list.append(node)

	## Select Vertex
	cmds.select(vert_list)