Automatically select all mesh faces facing up

[litma]

I need to make solid mesh out of a 3d scan of multiple objects and the fastest way I think is to extrude vertically all the faces facinf down or up Z axis. Is there a way to do that ?

thanks

[Joseph_Oster]

@litma

Is there a way to do that ?

Yes.

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[inno]

you can use Face Normals to get center and Normal of each mesh face:

then you can compare each Normal direction with something like the Z axis, eventually with a threshold, and filter mesh faces based on that True/False pattern:

[martinsiegrist]

I’d use the dot product

Selecting all Z-Axis planes on a Brep

The dot product is the cosine of the angle between the normal and a given vector. The cosine of 90° is 0. Two parallel vectors have a dot product of 1, opposing vectors -1… [image] I would strongly advise to use the dot product and not the angle. [image] Horizontal_Faces_dotproduct.gh (36.7 KB)