Convert MObject to MMatrix in python

[avogad]

Hi,

I'm looking for the best way to convert the worldMatrix of a MPxLocatorNode to a MMatrix in python but don't really know how to do it properly...

Does anyone have an idea ?!

Thanks 

[joojaa]

Depends if your evaluating it in compute or draw. If your doing this in draw, which is more likely, you could use:

        thisNode = self.thisMObject( )
 
        plug = OpenMaya.MPlug( thisNode, self.worldMatrix )
        plug = plug.elementByLogicalIndex( 0 )
        matrixObject = plug.asMObject(  )
 
        matrixData = OpenMaya.MFnMatrixData( matrixObject )
        matrix = matrixData.matrix( )

But off course you would need to figure out what number instance the node actually is, in case somebody instances you.

[avogad]

Thanks for the answer !

I want to do it in the compute function as I want to transform some points coordinates into the locator worldMatrix.
Actually, I'm rather looking for a way to get the worl matrix from its transform node... How should I do that ?

[joojaa]

Then you get the plug form the datablock. No maya at hand.

[avogad]

Indeed, I can get the locator's worldMatrix this way :

outWorldMatHandle = data.outputValue( self.worldMatrix )
outWorldMat = outWorldMatHandle.asMatrix()

However, here is the node's path : 

| transform1 | myLocatorNode1

and what I would like to get is, for example, the xFormMatrix from transform1.

Is there a way using the datablock to do this ?

Thanks