Get all bottom faces of brep

nguyentheta2002 · August 23, 2021, 3:50pm

Hi Guy,
I have one Brep as in attachment. How I can get all face bottom of this brep
Thanks
Select all bottom face of brep.3dm (151.1 KB)

martinsiegrist · August 23, 2021, 3:52pm

It would be simple in Grasshopper.

nguyentheta2002 · August 23, 2021, 3:59pm

I use deconstruct brep then sort by Z value of center point
But it only get for one face bottom.
In my brep have three faces

martinsiegrist · August 23, 2021, 4:05pm

You can calculate the dot product of the face normals and a Z-vector.

The filter the faces with the negative dot product…

nguyentheta2002 · August 23, 2021, 4:08pm

Hi
For this Brep I found 3 faces but Z vector not same direction

martinsiegrist · August 23, 2021, 4:19pm

nguyentheta2002 · August 23, 2021, 4:32pm

Thank @martinsiegrist so much
It work fine

martinsiegrist · August 23, 2021, 4:34pm

Thanks, please hit the solution button