Invisible 'cell shading' help needed

Hi all,
To start off i know how to cell shade, but the other day i saw someone who had the cell shading effect but with a transparent umm inner sphere.

It was basicly an invisible av but all i could see was the cell shading effect on the outsides. Dispite my efforts i'm unable to work how this is done, could someone help me out?

Thankyou!

Use the double-prim method for cell shading, not the twisted sphere method. Use a 32-bit texture on the outline prim. Use an invisiprim for the inner prim. The invisiprim will hide the avatar, and the portion of the 32-bit texture it covers, leaving you with the appearance of nothing but an outline.

Thunder, try this link:
/8/39/25130/1.html
And you may want to read this blog post as well, because it contains a pic of the effect:
http://dedricmauriac.wordpress.com/2007/02/03/a-tutorial-on-hiding/

If you see me on, IM me in world and I will give you the script.

I'm selling an avatar made that way, might be the one you saw. It was made using the standard cell-shading technique with an invisiprim as the inner of the prims.

* there's some pictures of the av here, about halfway down the page.
http://avatartoolbox.googlepages.com/Invisiprims.html

Go to my store, I have an example cell shaded sphere for sale for $0L.

Zebulon 175,75,26

Thanks all! i'm going to have a play around with this when i get online tonight

Hmm i still cant get this to work, what am i doing wrong?

1) two sphere's, one 500x500x500, the other 550x550x550.
2) small sphere has the invisprim script.
3) large sphere is textured black, them hollowed (95%) and the freebie 'totally clear' applied to the outside.
4) small sphere is placed perfectly inside the larger prim.

The result is just a black sphere *scratches head*

Try a smidge of transparency on the black.

ahaaaa, that done the job, thankyou!!