5 Responses to “Chapter 9”

1. Hi,

   Im currently working through this book (loving the book.. ) and even started to experiment with Maya API. Im a little stuck and was wondering if someone could please help me out. Im writing a script to find the average edge length but I cant seem to get it in world space. “getLength(doublePtr, NOT SURE WHAT I NEEDS HERE)”

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

   #
   #GET POLYGON SELECTION
   selection = om.MSelectionList()
   om.MGlobal.getActiveSelectionList( selection );
   iter = om.MItSelectionList ( selection, om.MFn.kGeometric );

   while not iter.isDone():
   dagPath = om.MDagPath()
   iter.getDagPath( dagPath )
   mObj = om.MObject()
   iter.getDependNode( mObj )
   dagPathHandle = dagPath.fullPathName()
   iterEdge = om.MItMeshEdge( mObj )

   while not iterEdge.isDone():
   edgeIndexListHandle =[]
   edgeIndexListHandle.append(iterEdge.index())
   print edgeIndexListHandle

   util = om.MScriptUtil()
   doublePtr = util.asDoublePtr()
   iterEdge.getLength(doublePtr)
   length = om.MScriptUtil.getDouble(doublePtr)
   print length
   iterEdge.next()
   iter.next()

   francois said this on February 12, 2012 at 4:51 pm | Reply

   • Hi Francois,

     Looks like the second parameter for MItMeshEdge.getLength() is an MSpace (enum) value, whose default value is object space. To do world space, you should try passing om.MSpace.kWorld.

     Adam said this on February 12, 2012 at 7:20 pm | Reply

2. When i try to pass om.MSpace.kWorld I get the following error:

   RuntimeError: (kInvalidParameter): Must have a DAG path to do world space transforms #

   Im a bit stuck on how to get this

   francois said this on February 13, 2012 at 1:56 pm | Reply

   • When you initialize your MItMeshEdge iterator, you must pass it an MDagPath (dagPath) rather than an MObject (mObj). When you initialize with an MObject, there may be multiple paths to the object (e.g., if it is instanced) and so it needs a unique DAG path in order to know where it is in world space.

     Adam said this on February 13, 2012 at 4:24 pm | Reply

3. Thanks Adam that did the trick

   francois said this on February 14, 2012 at 7:17 pm | Reply