As part of my Python script which interfaces with Abaqus, I want to setup a predefined stress field for a model. I'm going to use a user subroutine to do this.

I have two sets of questions:

I read the documentation at Abaqus > Scripting Interface > Python Commands > Predefined Field Commands > Stress Object and I noticed that the only two options for distributionType are UNIFORM and FROM_FILE. I expected that I would be able to use USER_DEFINED for distributionType so that my subroutine would be called. What should I use? FROM_FILE? USER_DEFINED? Or maybe FROM_FILE_AND_USER_DEFINED?

I've determined that there are two general methods of setting up a relatively complicated stress field in a model. I can either partition the part into many regions and assign a uniform stress field to each region or I can use the SIGINI user subroutine to gain finer control over the stress field. I don't believe that it is possible to use a analytical field to set up an initial stress state. Is there any method I am missing? Am I correct in my assertion that an analytical field cannot be used to set up an initial stress state?

Thank you in advance for the help!