pub fn face_normal(
model: &Model,
face: &Shape,
tol: Tolerances,
) -> OgeomResult<(Point, Vector)>Expand description
The direction a face presents, in space.
Sampled at the mean of its boundary in parameter space, which for a planar profile is exact everywhere and for a curved one is representative: a profile whose normal turns past perpendicular to the sweep somewhere across its own extent sweeps into a solid that passes through itself, and one sample is enough to decide which side the material lands on in every case this can build. A face with no boundary at all covers its whole surface, so the middle of the domain is the point to ask about.