reflectance normal
Technical term in computer graphics for the surface normal used in reflectance calculations.
The reflectance normal is used to calculate the surface's reflection properties.
法線 is a general term for a normal vector in geometry; 反射法線 specifically refers to the normal used in reflectance models.
Compound of 反射 (reflection) and 法線 (normal line), a direct calque of the English term 'reflectance normal'.