Can you clarify, what matrix do you get? Is it the matrix of the correct
object, but not the frame you want? Or is it all wrong?
I ran your Python code under Python API 2.0 and it worked for me, except I
skipped the part about inputMeshAttribute, and got my MFnMesh by getting a
MDagPath from an MSelectionList, using a utility function I have.
import maya.api.OpenMaya as om
import maya.api.OpenMayaAnim as oma
import maya_utils as mu # Sorry, this is a library I use at work.
meshFn = mu.mFnMeshFromName('pSphere1')
transFn = om.MFnDagNode(meshFn.dagPath()); print 'transFn:', transFn.name()
matrixPlugArray = transFn.findPlug("worldMatrix", 0)
matrixPlugArray.evaluateNumElements()
matrixPlug = matrixPlugArray.elementByPhysicalIndex(0)
time = oma.MAnimControl.currentTime()
timeContext = om.MDGContext(time); print 'time:', time
matrixO = matrixPlug.asMObject(timeContext)
fnMat = om.MFnMatrixData(matrixO)
matrix = fnMat.matrix(); print list(matrix)[12:16]
timeContext = om.MDGContext(time-1); print 'time-1:', time-1
matrixO = matrixPlug.asMObject(timeContext)
fnMat = om.MFnMatrixData(matrixO)
matrix = fnMat.matrix(); print list(matrix)[12:16]
and it prints
transFn: pSphereShape1
time: 2 kNTSCFrame
[-138.33162561773997, -552.7601891996619, 0.0, 1.0]
time-1: 1 kNTSCFrame
[-138.33162561773997, 185.2440600553723, 0.0, 1.0]
which matches what I have in my scene.
So it seems likely that the problem is your incoming MFnMesh. My guess is
that you either need to use MDataHandle::asMeshTransformed, or find a way
to get a dag path instead of a mesh. Perhaps you could link either a matrix
or a transform node to your plug, instead of linking a shape node.
I hope that helps :)
On Monday, 1 May 2017 19:29:20 UTC+10, David DeJuan wrote:
>
> Hi,
> thanks so much for answering. I have tried what you said, I read thet
> getValue is not possible to use in python, and that asMObject has to.
> But the results are the same. I'm having the translation of the current
> frame.
> Here it is my code in python:
>
> if( pPlug == DirectionMovNode.dirXAttribute ):
> # Get our custom input node attributes and values.
> inputMeshHandle = pDataBlock.inputValue(
> DirectionMovNode.inputMeshAttribute
> )
> inputMeshObj = inputMeshHandle.asMesh()
> meshFn = OpenMaya.MFnMesh(inputMeshObj)
>
> transFn = OpenMaya.MFnDagNode (meshFn.dagPath())
> matrixPlugArray = transFn.findPlug("worldMatrix")
> matrixPlugArray.evaluateNumElements()
> matrixPlug = matrixPlugArray.elementByPhysicalIndex(0)
> time = OpenMayaAnim.MAnimControl.currentTime()
> timeContext = OpenMaya.MDGContext(time-1)
> matrixO = matrixPlug.asMObject(timeContext)
> fnMat = OpenMaya.MFnMatrixData(matrixO)
> matrix = fnMat.matrix()
> result = '% .06f, % .06f, % .06f, % .06f,\n% .06f, % .06f, %
> .06f, % .06f,\n% .06f, % .06f, % .06f, % .06f,\n% .06f, % .06f, % .06f, %
> .06f,\n'
> print result % (matrix(0, 0), matrix(0, 1), matrix(0, 2),
> matrix(0, 3), matrix(1, 0), matrix(1, 1), matrix(1, 2), matrix(1, 3),
> matrix(2, 0), matrix(2, 1), matrix(2, 2 ), matrix(2, 3), matrix(3, 0),
> matrix(3, 1), matrix(3, 2), matrix(3, 3))
>
> # Set the output data.
> dirX = pDataBlock.outputValue( DirectionMovNode.dirXAttribute
> )
> dirX.setFloat(matrix(3, 0))
>
>
>
>
>
> El lunes, 1 de mayo de 2017, 6:06:11 (UTC+2), Michael Boon escribió:
>>
>> I've done a similar thing successfully in Python, but I used
>> MPlug::asMObject and MFnMatrixData::matrix instead of MPlug::getValue. I
>> don't remember if I tried using getValue, but I do remember that I found it
>> extremely finicky and I tried a lot of approaches before I found one that
>> gave me a result. Maybe this approach will work for you too.
>>
>> This is in Python, but I think it will translate to C++:
>>
>> matMObj = matrixPlug.asMObject(timeContext)
>> mat = om.MFnMatrixData(matMObj).matrix()
>>
>>
>>
>>
>> On Monday, 1 May 2017 04:50:34 UTC+10, David DeJuan wrote:
>>>
>>> Hi,
>>> I'm trying to do a Node, where the input is a mesh and get the
>>> translation matrix of it in the previous frame. But I don't get it.
>>> I have tried using the MPlug getValue setting the MDGContext one frame
>>> before, but it doesn't work.
>>> This is the code, it is in C++
>>>
>>> MStatus node::compute(const MPlug& plug, MDataBlock& data){
>>>
>>> if (plug == dirX) {
>>> MDataHandle dirXHandle = data.outputValue(dirX);
>>> MDataHandle dirXHandleOld = data.outputValue(dirXOld);
>>> MTime time = MAnimControl::currentTime();
>>>
>>> MDGContext timeContextOld(time - 1);
>>>
>>> MObject inputMeshObj = inputMeshHandle.asMesh();
>>> MFnMesh meshFn(inputMeshObj);
>>>
>>> MDagPath dagPath;
>>> dagPath = meshFn.dagPath();
>>> MFnDagNode transFn(dagPath);
>>>
>>> MPlug matrixPlugArray = transFn.findPlug("worldMatrix");
>>> matrixPlugArray.evaluateNumElements();
>>> MPlug matrixPlug = matrixPlugArray.elementByPhysicalIndex(0);
>>>
>>> MObject matrixO;
>>> matrixPlug.getValue(matrixO, timeContextOld);
>>> MFnMatrixData fnMat(matrixO);
>>> MVector res = fnMat.transformation().getTranslation(MSpace::kWor ld);
>>>
>>> // Set the output data.
>>> dirXHandle.setFloat(0.0);
>>> dirXHandleOld.setFloat(res.x);
>>> }else {
>>> return MS::kUnknownParameter;
>>> }
>>>
>>> return MS::kSuccess;
>>> }
>>>
>>>
>>> I am wondering also how the cacheFrame node works.
>>> Can anyone help me?
>>> Thanks
>>>
>>
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