Сделано с помощьюsdf2stl.saej.in

Полный код SDF:

float sdGoursat(vec3 position, float radius) // 0 <= radius < .75 { float p4 = dot(position * position, position * position); float p2 = dot(position, position); // f(x,y,z) = x^4 + y^4 + z^4 - x^2 - y^2 - z^2 + radius float f = p4 - p2 + radius; // ∇f(x,y,z) = {4x^3 - 2x, 4y^3 - 2y, 4z^3 - 2z} vec3 df = 4.