I have a tag plugin that changes the position of the children of the object where the tag is attached to.
This works ok in the viewport, but when rendering it does not work.
I assume that the tag is not 'executed' during rendering?
What should I do to make it working?
I did some ore testing and now I guess it is a programming error.
So, I guess my assumption was wrong.
without seeing your code or any error message it is impossible to give any advice.
But "works in viewport but not in rendering" sounds like you are using c4d.documents.GetActiveDocument() somewhere. See also BaseDocument Manual.