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Transforming Nodal FieldOutput to Element Coord Sys (local Coord Sys)

Transforming Nodal FieldOutput to Element Coord Sys (local Coord Sys)

Transforming Nodal FieldOutput to Element Coord Sys (local Coord Sys)

(OP)
First of all I'd like to say thank you for your help.
Right now I am working on a python script to calculate a new value out of shell Section Forces (SF) and the velocitys at the Nodes (V,VR) from the fieldOutput.
Everything works fine for a simple plate but for complex structures I have the problem that the Section Forces are defined with respect to the local coord systems (calculated at integration point) of each element and the nodal velocitys in the global coord system. Therefore I need to transform the nodal valuse into the local element coordinate system, calculate the values out of SF and V and after that retransform them back into the global system.

So I need the transformation Matrix aij = ei'*transpose(ej), (ei': base vectors of element system and ej base vectors of nodes) to perform
V' = A*V
I think if got the base vectors of the local element coordinate system (e1',e2',e3') for each element (odbFile.steps[stepName].frames[i].fieldOutputs['SF'].getSubset(position=CENTROID).values[0].localCoordSystem) but I can't find any Information in the documentation or google to get the nodal base vectors...

I also think that there must be a simpler way to perform the transformation. getTransformationField doesn't help me... And set *NODE OUTPUT, GLOBAL=NO, in the input file didn't allow a retransformation (http://www.eng-tips.com/viewthread.cfm?qid=361956)...
Thank you for your help!

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