k3d/share/shaders/k3d_volcube.sl:117:    float activeVol = 0;
k3d/share/shaders/k3d_volcube.sl:120:    activeVol = active_volume(Pos,vol_mult,vol_offset);
k3d/share/shaders/k3d_volcube.sl:123:    return activeVol + (dens-2);
