Selecting all the outer surfaces of a group of polysurfaces

I’m trying to select the outer surfaces of a group of poly-surfaces.
I want to measure the area and solar incidence with laydybug and I therefore only need the outer surface…not the sides, nor the inner surface…and I have no idea how to do this…Any suggestions?

rgds
anders

If this is all the geometry you have without any scripts to get you there, I would recommend to

  • first eliminate the small edges either based on their area or their normal
  • have a bounding box that covers all breps together
  • get center of the bounding box.
  • draw vectors from the center to the panels.
  • compare the drawn vector with the normal of the panels

that way you can differentiate front from back