code: public double getScaleToUnityBox(){
          double largestEdge = 0;
          largestEdge = Math.max(largestEdge, maxX - minX);
          largestEdge = Math.max(largestEdge, maxY - minY);
          largestEdge = Math.max(largestEdge, maxZ - minZ);
          return 1.0 / largestEdge;
      }
docs: Gets the scale factor by which the box needs to be multiplied
  that it fits into a cube with edge length 1.