Function draft 

pub fn draft(
    topo: &mut Topology,
    solid: SolidId,
    draft_faces: &[FaceId],
    pull_direction: Vec3,
    neutral_point: Point3,
    angle_radians: f64,
) -> Result<SolidId, OperationsError>

Apply a draft angle to selected faces of a solid.

Tapers the specified faces by angle_radians relative to pull_direction. The neutral plane is defined by neutral_point and pull_direction: vertices on the neutral plane stay fixed while vertices above/below are moved outward/inward.

Errors

Returns an error if:

• angle_radians is zero or negative
• pull_direction is zero-length
• Any draft face is NURBS
• The solid is invalid