Thicken now moves faces through the same mover as Offset Surface. Spheres, cones, tori and B-spline faces thicken as well as planes and cylinders, and a thickness that would fold a curved face over is refused. Where thickened faces meet at a sharp edge, a wall closes the gap and corners are closed with flat patches. Thickening into an inside corner is still refused with a clear message.
Closes#765.
Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Offsets picked faces along their normals into a new surface body: planes and cylinders move exactly, other faces get a fitted B-spline within tolerance, and offsets that would fold over are refused. Adds the SurfaceOffset feature (noted under format 18), the surface.offset engine command and an Offset Surface dialog.
Closes#758.
Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
