Well, I'll try to cut it to just one question.
I tried my best, and I think someway it should be working, but still the
*output
array attribute* is empty (all the values are set to the default value
0,0,0).
So I think there's something wrong in the way I fill up the output array
attribute. I've been striving for days now, but I can't get out of this bog.
Can somebody please help me on how the *MArrayDataBuilder *works?
I shortened the code and bolded the questionable parts to make it more
readable:
thank you guys!
class AttachToMesh(OMMPx.MPxNode):
def compute(self,plug,dataBlock):
if plug == AttachToMesh.a_outPosition:
inMesh = dataBlock.inputValue(AttachToMesh.a_inMesh).asMesh ()
positionOffsetValue = dataBlock.inputValue(AttachToMesh.
a_positionOffset).asFloat()
* dataHandleArrayOutPosition *
*= dataBlock.outputArrayValue(AttachToMesh.a_outPosition)
dataBuilderOutPosition = dataHandleArrayOutPosition.builder()*
geoIterator = OM.MItGeometry(inMesh)
mFnMesh = OM.MFnMesh(inMesh)
vertexPosition = OM.MPoint()
normals = OM.MFloatVectorArray()
mFnMesh.getVertexNormals(False, normals)
while not geoIterator.isDone():
vertexPosition.x = geoIterator.position().x + ( normals[
geoIterator.index()].x * positionOffsetValue )
vertexPosition.y = geoIterator.position().y + ( normals[
geoIterator.index()].y * positionOffsetValue )
vertexPosition.z = geoIterator.position().z + ( normals[
geoIterator.index()].z * positionOffsetValue )
* dataHandleOutPosition *
*= dataBuilderOutPosition.addElement(geoIterator.index())
dataHandleOutPosition.set3Double(vertexPosition.x, vertexPosition.y,
vertexPosition.z)*
geoIterator.next()
* dataHandleArrayOutPosition*
*.set(dataBuilderOutPosition) dataBlock.setClean(plug)*
def nodeInitializer():
AttachToMesh.a_inMesh = mFnTypedAttr.create("inputMesh", "inMesh", OM.
MFnData.kMesh)
AttachToMesh.a_positionOffset = mFnAttr.create("positionOffset",
"posOff", OM.MFnNumericData.kFloat, 0.0)
* AttachToMesh.a_outPosition = mFnAttr.create("outPosition", "outPos",
OM.MFnNumericData.k3Double, 0.0)*
mFnAttr.setKeyable(0)
mFnAttr.setWritable(0)
mFnAttr.setArray(1)
mFnAttr.setUsesArrayDataBuilder(1)
Il giorno mercoledì 30 luglio 2014 01:21:38 UTC+2, Enrico Losavio ha
scritto:
>
> Hi everyone!
>
> I'm trying to write a sort of River node, but I ran into some difficulties
> (obviously :) ) and any help would be greatly appreciated!
>
> Basically i want a DG node that can
>
> - accept geometry as an input
> - retrieve mesh information
> - make up his own calculations based on the mesh information and a few
> custom attributes
> - have an array of MPoints (or k3Double i guess) as output to be piped
> into each locator
> - have the output updated every time an attribute or the mesh itself
> changes
>
> As far as I know, the MPxDeformerNode is the only way to access the
> geometry data. But I don't want to deform the mesh, just query information.
> And yet I don't fully understand how the push-pull mechanism works in this
> case. In a custom DG node i would use the "if plug == attribute" to force
> the evaluation, but in this case...?
> I've already jot down the basic structure for the node, but it doesn't
> work as it should.
> In Maya I loaded the plugin, applied the deformer to a simple cube, and
> fed each value of the array into the Translate attribute of specifically
> created locators (that thus went in the correct position, one on each
> vertex)
> If I tweak the mesh, the locators remain in the same position, don't
> follow the vertices. If I change the value of the positionOffset attribute,
> nothing happens.
> But I noticed that if i tweak the mesh and then change the value of the
> attribute, the position of all the locators suddenly updates as though the
> mesh is read properly, but the positionOffset value remains the previous
> one.
>
> Here's a simplified version of the code I wrote...:
>
> class AttachToMesh(OMMPx.MPxDeformerNode):
>
>
> mObj_positionOffset = OM.MObject()
> mObj_outPosition = OM.MObject()
>
>
> def __init__(self):
> OMMPx.MPxDeformerNode.__init__(self)
>
>
> def deform(self, dataBlock, geoIterator, matrix, geometryIndex):
>
> # RETRIEVE GEOMETRY DATA
> input = OMMPx.cvar.MPxDeformerNode_input
> dataHandleInputArray = dataBlock.outputArrayValue(input)
> dataHandleInputArray.jumpToElement(geometryIndex)
> dataHandleInputElement = dataHandleInputArray.outputValue()
>
> inputGeom = OMMPx.cvar.MPxDeformerNode_inputGeom
> dataHandleInputGeom = dataHandleInputElement.child(inputGeom)
> inMesh = dataHandleInputGeom.asMesh()
>
>
> # POSITION OFFSET
> dataHandlePositionOffset = dataBlock.inputValue(AttachToMesh.
> mObj_positionOffset)
> positionOffsetValue = dataHandlePositionOffset.asFloat()
>
> # OUT POSITION
> dataHandleArrayOutPosition = dataBlock.outputArrayValue(
> AttachToMesh.mObj_outPosition)
> dataBuilderOutPosition = dataHandleArrayOutPosition.builder()
>
> vertexPosition = OM.MPoint()
> mFnMesh = OM.MFnMesh(inMesh)
>
> normals = OM.MFloatVectorArray()
> mFnMesh.getVertexNormals(False, normals)
>
>
> while not geoIterator.isDone():
>
>
> vertexPosition.x = geoIterator.position().x + ( normals[
> geoIterator.index()].x * positionOffsetValue )
> vertexPosition.y = geoIterator.position().y + ( normals[
> geoIterator.index()].y * positionOffsetValue )
> vertexPosition.z = geoIterator.position().z + ( normals[
> geoIterator.index()].z * positionOffsetValue )
>
> dataHandleOutPosition = dataBuilderOutPosition.addElement(
> geoIterator.index())
> dataHandleOutPosition.set3Double(vertexPosition.x,
> vertexPosition.y, vertexPosition.z)
>
> geoIterator.next()
>
> dataHandleArrayOutPosition.set(dataBuilderOutPosition)
>
> #here I'm not sure which setClean function I'm supposed to use...
> in this case I chose dataBlock.setClean
> #dataHandleArrayOutPosition.setAllClean()
>
> dataBlock.setClean(AttachToMesh.mObj_outPosition)
>
>
> def nodeInitializer():
> mFnAttr = OM.MFnNumericAttribute()
>
>
> AttachToMesh.mObj_positionOffset = mFnAttr.create("positionOffset",
> "posOff", OM.MFnNumericData.kFloat, 0.0)
> mFnAttr.setKeyable(1)
>
> AttachToMesh.mObj_outPosition = mFnAttr.create("outPosition", "outPos"
> , OM.MFnNumericData.k3Double, 0.0)
> mFnAttr.setKeyable(0)
> mFnAttr.setWritable(0)
> mFnAttr.setArray(1)
> mFnAttr.setUsesArrayDataBuilder(1)
>
> AttachToMesh.addAttribute(AttachToMesh.mObj_outPosition)
>
> AttachToMesh.attributeAffects(AttachToMesh.mObj_positionOffset,
> AttachToMesh.mObj_outPosition)
>
>
>
> Thank you in advance for any reply!!
>
>
>
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