The next step is to duplicate the original lattice. You can do this either from the Edit menu or by the key combination Command D (Macintosh) or Control D (PC). Then take the duplicated lattice into the terrain editor and invert the lattice (one of the selections at the top left hand side of the terrain editor window).

Now hold down on the SHIFT key and carefully paint around the outside of your inverted lattice to get rid of the excess white material. As you can see from the image on the right, I also used the gradient on the right to help remove most of the unwanted background once it was painted down to black. When you are done, all that should remain is the white areas inside your window.

**For Bryce 5 users, Unpatched versions may see a line of white at the top of the inverted terrain. You can clip that section out.

You will then have to position the glass lattice inside the window frame lattice. I did this with the aid of the right view camera. The final step is now to create a suitable glass material.