use implement::math::vector::Mat2x1< f64 >;
use implement::math::vector::Mat3x1< f64 >;
use implement::math::vector::Mat4x1< f64 >;
pub struct SurfInteract {
_point: Mat2x1< f64 >,
_dpdu: Mat3x1< f64 >,
_dpdv: Mat3x1< f64 >,
_normal: Mat3x1< f64 >,
_dndu: Mat3x1< f64 >,
_dndv: Mat3x1< f64 >,
}