hi together,
I have been trying to write a custom deformer using the maya python api which
basically is a shrink wrap deformer using a custom vector to project each
vertex to the another mesh.
The deformer works fine as is. I really would like to add one option though
which I cannot figure out how to achieve as I am new to the api and the logics
of it in general. I would like to add an array attribute to the deformer node
which for each input geometry vertex saves the index of another vertex which
should be included into the calculation of the deform function.
My question is: How do I create the array attribute and also how do I populate
and access it in the deform function?
I guess I have already somewhat figured out how to create the Array using
setArray() function and also adding child attributes to it but I still have
troubles understanding where and how to populate and access the array
attribute. There is a lot of information out there concerning MPlugs and
arrayDataBuilder but I simply have not been able to understand it. Can somebody
provide me with an example or explain me how to properly do using the python
api? Any help is greatly appreciated!
This is the code, that I was able put together with the examples available
online:
import maya.OpenMaya as OpenMaya
import maya.OpenMayaAnim as OpenMayaAnim
import maya.OpenMayaMPx as OpenMayaMPx
import maya.cmds as cmds
class surfaceSlideDeformer(OpenMayaMPx.MPxDeformerNode):
kPluginNodeId = OpenMaya.MTypeId(0x00000012)
kPluginNodeTypeName = "surfaceSlideDeformer"
bindData = OpenMaya.MObject()
sampleWeights = OpenMaya.MObject()
def __init__(self):
OpenMayaMPx.MPxDeformerNode.__init__(self)
self.accelParameters = OpenMaya.MMeshIsectAccelParams() # speeds up
intersect calculation
def deform(self, block, geoItr, matrix, index):
# get ENVELOPE
envelope = OpenMayaMPx.cvar.MPxGeometryFilter_envelope
envelopeHandle = block.inputValue(envelope)
envelopeVal = envelopeHandle.asFloat()
if envelopeVal!=0:
# get target MESH (as worldMesh)
targetHandle = block.inputValue(self.targetMesh)
inTargetMesh = targetHandle.asMesh()
if not inTargetMesh.isNull():
#get target fn mesh
inTargetFn = OpenMaya.MFnMesh(inTargetMesh)
inMesh = self.get_input_geom(block, index)
inMeshFn = OpenMaya.MFnMesh(inMesh)
inPointArray = OpenMaya.MPointArray()
inMeshFn.getPoints(inPointArray, OpenMaya.MSpace.kWorld)
# create array to store final points and set to correct length
length = inPointArray.length()
finalPositionArray = OpenMaya.MPointArray()
finalPositionArray.setLength(length)
finalPositionArray = inPointArray
# loop through all points
while not geoItr.isDone():
w = self.weightValue(block, index, geoItr.index())
point = inPointArray[geoItr.index()]
raySource = OpenMaya.MFloatPoint(point.x, point.y, point.z)
rayDirection = OpenMaya.MVector()
inMeshFn.getVertexNormal(geoItr.index(), False,
rayDirection)
rayDirection = OpenMaya.MFloatVector(rayDirection.x, 0.0,
rayDirection.z)
hitPoint = OpenMaya.MFloatPoint()
# rest of the args
hitFacePtr = OpenMaya.MScriptUtil().asIntPtr()
idsSorted = False
testBothDirections = True
faceIds = None
triIds = None
accelParams = self.accelParameters
hitRayParam = None
hitTriangle = None
hitBary1 = None
hitBary2 = None
maxParamPtr = 99999999
hit = inTargetFn.closestIntersection(raySource,
rayDirection,
faceIds,
triIds,
idsSorted,
OpenMaya.MSpace.kWorld,
maxParamPtr,
testBothDirections,
accelParams,
hitPoint,
hitRayParam,
hitFacePtr,
hitTriangle,
hitBary1,
hitBary2)
if hit:
finalPositionArray.set(OpenMaya.MPoint(point.x +
envelopeVal*w*(hitPoint.x-point.x), point.y +
envelopeVal*w*(hitPoint.y-point.y), point.z +
envelopeVal*w*(hitPoint.z-point.z)), geoItr.index())
else:
finalPositionArray.set(point, geoItr.index())
geoItr.next()
inMeshFn.setPoints(finalPositionArray, OpenMaya.MSpace.kWorld)
def get_input_geom(self, block, index):
input_attr = OpenMayaMPx.cvar.MPxGeometryFilter_input
input_geom_attr = OpenMayaMPx.cvar.MPxGeometryFilter_inputGeom
input_handle = block.outputArrayValue(input_attr)
input_handle.jumpToElement(index)
input_geom_obj =
input_handle.outputValue().child(input_geom_attr).asMesh()
return input_geom_obj
def creator():
return OpenMayaMPx.asMPxPtr(surfaceSlideDeformer())
def initialize():
gAttr = OpenMaya.MFnGenericAttribute()
mAttr = OpenMaya.MFnMatrixAttribute()
nAttr = OpenMaya.MFnNumericAttribute()
tAttr = OpenMaya.MFnTypedAttribute()
cAttr = OpenMaya.MFnCompoundAttribute()
outMesh = OpenMayaMPx.cvar.MPxGeometryFilter_outputGeom
surfaceSlideDeformer.targetMesh = gAttr.create("targetMesh", "target")
gAttr.addDataAccept(OpenMaya.MFnData.kMesh)
surfaceSlideDeformer.addAttribute(surfaceSlideDeformer.targetMesh)
surfaceSlideDeformer.sampleWeights =
nAttr.create('sampleWeights','sampleWeights',OpenMaya.MFnNumericData.k2Int)
nAttr.setArray(True)
surfaceSlideDeformer.bindData = cAttr.create('bindData','bindData')
cAttr.setArray(True)
cAttr.setStorable(True)
cAttr.addChild(surfaceSlideDeformer.sampleWeights)
surfaceSlideDeformer.addAttribute(surfaceSlideDeformer.bindData)
surfaceSlideDeformer.attributeAffects(surfaceSlideDeformer.bindData,
outMesh)
surfaceSlideDeformer.attributeAffects(surfaceSlideDeformer.targetMesh,
outMesh)
cmds.makePaintable('surfaceSlideDeformer', 'weights',
attrType='multiFloat', shapeMode='deformer')
def initializePlugin(obj):
plugin = OpenMayaMPx.MFnPlugin(obj, 'Degner', '1.0', 'Any')
try:
plugin.registerNode('surfaceSlideDeformer',
surfaceSlideDeformer.kPluginNodeId, creator, initialize,
OpenMayaMPx.MPxNode.kDeformerNode)
except:
raise RuntimeError, 'Failed to register node'
def uninitializePlugin(obj):
plugin = OpenMayaMPx.MFnPlugin(obj)
try:
plugin.deregisterNode(surfaceSlideDeformer.kPluginNodeId)
except:
raise RuntimeError, 'Failed to deregister node'
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