int outSize = 50;

field#0(3)[] F = tent ⊛ load("../../data/ring.nrrd");

strand sample (int ui, int vi, int wi) {
   real uu = lerp(-1.0, 1.0, -0.5, real(ui), real(outSize)-0.5);
   real vv = lerp(-1.0, 1.0, -0.5, real(vi), real(outSize)-0.5);
   real ww = lerp(-1.0, 1.0, -0.5, real(wi), real(outSize)-0.5);
   vec3 pos = [uu, vv, ww];
   output real val = -0.6; 

   update {
      val = F(pos) if (inside(pos,F)) else -0.6;
      stabilize;
   }
}

initially [ sample(ui, vi, wi) | wi in 0..(outSize-1), vi in 0..(outSize-1), ui in 0..(outSize-1) ];