Selecting all the outer surfaces of a group of polysurfaces

[anders]

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

[idilgumruk]

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

[anders]

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?

[kev.r (Kevin)]

I answered this in your other post here:

Adjusting normals

Compare your normals with the Dot Product component. If you get a negative result the square needs to be flipped. Here’s a simple example that uses the Dot Product component to compare surface normals to a Unit Z vector. Positive results are colored blue, negative results are colored red, and zero results are colored yellow. [dot_prod_01] [dot_prod_02] dot_product_example.gh (38.5 KB) -Kevin

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.

-Kevin