How to create nodal point stress results for node set in optistruct

Default stress results in OS are elemental.

You can request corner data, and in HyperView use averaging to calculate stresses in the nodes.

For solid elements you could request GPSTRESS and in this case select a specific node Set.

OptiStruct cannot export directly in unv format. Only H3D, OP2, pch, ...

thank you , i will try

thank you , unfortunately, Optistruct not generated for me separately h3d files for node sets. I defined two node sets , which is I need two seperatly h3d files. Mybe I have to define Element set ? 

You get always only ONE h3d file at the end of analysis. Use Hyperview to load results and export to H3D as many as you want.

optistrcut will generate only one result file per file type (OP2, H3D, pch,...).

you could have mentioned this upfront in your question, by the way.

it is always helpful to understand the whole picture for a better answer.

Depending on what you'll do a HV script or even Compose could be very helpful.