# Removing coplanar surfaces

I have made a mass model of a building and have divided the exterior walls into 4x5 surfaces. I would now like to delete any surfaces that are overlapping (see image). I am using a grasshopper script for the surface division and the deletion of the overlapping surfaces cannot happen before the surface division.

overlapping surfaces.3dm (2.2 MB)

Hej Mikkel -

I’m not sure why not?
In Grasshopper, I’d turn those - what looks like - 3 buildings into one single object and then run the surface division algorithm on the result.
-wim

Hi Wim,
Thank you for such a quick reply!
I’ve tried to use a BooleanUnion before the surface division, but the faces from the smaller of the buildings are still there.
overlapping.gh (69.3 KB)
Building.3dm (148.4 KB)

BooleanUnion works in Rhino itself; I opened your GH file but there’s so much going on that I can’t quite tell what you’re trying to accomplish. Can you please simplify the definition down to the part where you’re trying to get the individual surfaces, after the union?

Hi Brian,
What i am trying to accomplish is taking the mass model and dividing it into the seperate surfaces so that i can calculate solar radiance for each surface. Later on, i am creating rooms for the surfaces with the most and the least radiance, so that i can do a indoor climate simulation. The trouble is that when surfaces are created for the overlapping walls, that will mess with my overall results. So simply put, i would like for my grasshopper script to convert a mass model into a grid of 4 by 5 meter surfaces, without overlapping.

Do you want to remove the overlapping surfaces completely, or do you want to convert the overlapping surfaces into a single surface? Again, if you can send the GH definition for the simplification process, and attach both the original file and a file with the desired results (not just a screenshot with markup, because it’s easy to misinterpret markups), perhaps we can help guide you toward an answer.

Hi Brian, and thank you for your patience. The final product should be the exterior walls divided into the individual surfaces. What the best way to do this is, i am not sure. My thinking is taht either the initial mass model has to be modified before the individual surfaces are created or a method for finding an deleting overlapping surfaces should made. Attached is my current progress and surfaces creation. I have also baked the surface division result and saved what is currently made by my grasshopper script, and what i would like for it to ideally be.

Building.3dm (139.1 KB)
Context.3dm (571.0 KB)
Current building surfaces.3dm (2.7 MB)
Desired building surfaces.3dm (2.3 MB)
Surface creation.gh (72.6 KB)

Thank you.
Mikkel