Selecting bottom faces of exploded geometry

Hi everyone,
I’m trying to select the the bottom face of each box (volume) after exploding them. (these boxes (geometry) were resulted from the intersection of columns with floor elements retrieved from revit).

I’m doing so by:

  • getting the center point of each face for every single box.
  • extracting the z values from these center points
  • find the minimum z value in a surface for each box
  • finally sorting the faces according to the lowest z values.

But for some reason I can’t achieve the desired results. The final step is what I think I’m not doing properly, or maybe the whole approach is just not good, idk.


Try using the surface normal - the bottom face should have the negative Z vector (0, 0, -1)


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Thanks a lot Mike, that was helpful

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