Function outward_offset 

pub fn outward_offset(
    verts: &[[f64; 3]],
    faces: &[[usize; 3]],
    d: f64,
) -> OffsetMesh

Compute an outward-offset mesh from a triangle soup.

Equivalent to OffsetMesh::from_triangle_soup(verts, faces).offset(d) for positive d, but named explicitly for clarity.