Function intersect_plane_torus 

pub fn intersect_plane_torus(
    torus: &ToroidalSurface,
    normal: Vec3,
    d: f64,
) -> Result<Vec<IntersectionCurve>, MathError>

Intersect a plane with a toroidal surface.

The section is a degree-4 curve, but for each v the u values solve in closed form (see plane_torus_crossings), so it is sampled by a v-scan and each connected loop is fitted to a NURBS curve.

Errors

Never returns an error today (curve-fit failures drop the affected loop); the Result is kept for signature parity with the other plane-analytic intersectors.