Shaping Subdivision Meshes with Curves

        int num = nprimitives(1);
vector pos[] = {};

vector p = prim(1, 'P', 0);
append(pos, p);

for(int i = 0; i < num; i++){
    p = primuv(1, 'P', i, v@uv);
    append(pos, p);
}

p = prim(1, 'P', num - 1);
append(pos, p);

v@P = spline('bspline', v@uv[1], pos);