Hi Stan, I'm sorry but currently there isn't any mechanism set up for controlling the DXF, PDF, or AI options like there is for mesh exports. It's only the mesh format exports (obj, stl, 3ds, lwo, fbx, and skp) which pay attention to those passed in parameters including NoUI=true.

That is something I can add in for v4 but for v3 there isn't any way set up to control it from script.

- Michael