Get all bottom faces of brep

Grasshopper
1

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)

image

2

It would be simple in Grasshopper.

3

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

4

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

The filter the faces with the negative dot product…

5

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

image
image735Ă—305 30.1 KB

6

image
image1920Ă—983 78.6 KB

brep_face_normals.gh (40.0 KB)

3 Likes
7

Thank @martinsiegrist so much
It work fine

1 Like
8

Thanks, please hit the solution button

image

1 Like