Hi

in my INP file, I added *Element Output,POSITION=AVERAGED AT NODES, directions=YES in order to have nodal stress result.  I think I only have unique nodal stress result and I don't have elemental stress result in odb. After this, I got a lot problems when plotting the data. For example, 

I like to create a session field of volumetric strain(E11+E22+E33). My model has 4 instances. I decided to use Python as below. Yes I can create the session field of volumetric strain. But when i plot the field, it shows me an error of selected primary field variable is not available to the current frame in the current display group.  For the same code, if I replace E by U and E11 by U1, everything is fine. I don't know what is going on for this nodal stress field.

Can you help me take a look at the below script? Thank you so much for your help. I appreciate it.

Also, is it possible to output both Node Average and Integration Point stress results from INP file?

import os, os.path, sys
from odbAccess import *
import visualization  
from abaqusConstants import *

odb_name ='Job_Dayfr3_to255_72A_4Part_UnDrainSide_DrainTop_NodeStress.odb'  
odb_object = session.openOdb(name=odb_name ,readOnly=False)

frame=odb_object.steps['Step_180'].frames[2]
E_thisframe = frame.fieldOutputs['E'].getSubset(elementType='C3D8P',position=NODAL)
EvolField = E_thisframe.getScalarField(componentLabel="E11")+E_thisframe.getScalarField(
    componentLabel="E22")+E_thisframe.getScalarField(componentLabel="E33")
scratchOdb = session.ScratchOdb(odb=odb_object)
#scratchOdb = odb_object
sessionStep = scratchOdb.Step(name='Session Step', description='Customized Step for Evol', domain=TIME, 
    timePeriod=1.0)
sessionFrame = sessionStep.Frame(frameId=0, frameValue=0.0,description='Session Frame')
FieldOutput_Evol = sessionFrame.FieldOutput(name='EVol',description='Customized Step for Evol', field=EvolField)
                
session.linkedViewportCommands.setValues(_highlightLinkedViewports=True)

print 'Done Processing'​​​​​​​