Thank you for usefull information. I found a script that does exactly what I need. http://polycount.com/discussion/174582/adn-modeler-tools-smart-modeling-scripts-for-maya/p2 ADN modeller + Automap function
You can planar map the mesh or part of the mesh you'd like to do this to, then run this script to select hard edges: polySelectConstraint -mode 3 -type 0x8000 -sm 1;resetPolySelectConstraint; And then just use the Cut UV Edges tool, and unfold the resulting islands.