Local Blend Shapes using ICE Attributes through scripting

[Eric Thivierge]

Hey all,

I'm trying to create local relative blend shapes using Python and I am 
getting some strange results when applying them back. I'm getting the 
PointPosition and PointReferenceFrame ICE Attributes for speed / 
convenience. If I do the same math via ICE I get the correct results so 
it's either I have a mistake somewhere in the math in the python or 
there is a discrepancy in the data when getting it through Python.

Any thoughts?

# Python
def createLocalShape(tgtObj, srcObj):

    clstr = tgtObj.ActivePrimitive.Geometry.Clusters("Shape")
    if not clstr:
        clstr = 
tgtObj.ActivePrimitive.Geometry.AddCluster(constants.siVertexCluster, 
"Shape")

    tgtPointPosICEArray = 
list(tgtObj.ActivePrimitive.Geometry.GetICEAttributeFromName("PointPosition").DataArray)
    blendVector = XSIMath.CreateVector3()
    utilXfo = XSIMath.CreateTransform()
    utilMat3 = XSIMath.CreateMatrix3()

    srcPointPosICEArray = 
list(srcObj.ActivePrimitive.Geometry.GetICEAttributeFromName("PointPosition").DataArray)
    srcPointRefFrameICEArray = 
list(srcObj.ActivePrimitive.Geometry.GetICEAttributeFromName("PointReferenceFrame").DataArray)

    newShape = clstr.AddProperty("SimpleDeformShape", 0, srcObj.Name + 
"_shape")
    newShapeValues = list([list(x) for x in newShape.Elements.Array])

    for i, eachItem in enumerate(srcPointPosICEArray):

        blendVector.Sub(srcPointPosICEArray[i], tgtPointPosICEArray[i])
        refFrame = srcPointRefFrameICEArray[i]
        refArray = refFrame.Get2()
        utilMat3.SetIdentity()
        utilMat3.Set(refArray[0], refArray[1], refArray[2], 
refArray[3], refArray[4], refArray[5], refArray[6], refArray[7], 
refArray[8])
        utilMat3.InvertInPlace()
        utilXfo.SetIdentity()
        utilXfo.SetRotationFromMatrix3(utilMat3)

        blendVector.MulByTransformationInPlace(utilXfo)

        newShapeValues[0][i] = blendVector.X
        newShapeValues[1][i] = blendVector.Y
        newShapeValues[2][i] = blendVector.Z

    newShape.Elements.Array = newShapeValues
    xsi.FreezeObj(newShape)

    return newBlendShapes

Thanks,
Eric T.