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?


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

Thank you!
Sorry about only sharing a screenshot…I was in the early planning/concept stage and the building ended up much more complicated so I couldn’t use the bounding box method…but your suggestion helped me clarify the thinking a lot.

How would you recommend that I ’ compare the drawn vector with the normal of the panels’?
I working on a continuation of the same project and struggling with the comparison between two sector sets (one for the surface normal and a collections of normal vectors for squares on the same surface)…

Have a look at this process… any suggestions?

I answered this in your other post here:

Please don’t post multiple threads about the same topic. If you have additional information or questions it is better post again to the original thread.