Silhouette People Shader?

[Artcrimes147]

Hi everyone; first of all, what a great community!

Long time lurker here - have benefited from a lot of you guys, but now I have a question I simply can't find an answer to.

How would you go about making a material that is a flat color rendition of a 3D form, but does not show the "backside" of the geometry?

Often an effect for archviz, the completely black person silhouette with a 50% opacity, but you don't see the arms or legs geometry through on the otherside?

Attached image, the problem in question!

A million thanks in advance!

[Njen]

To be honest, I would do this in comp. Render out the people held out against the scene, then merge in a constant colour using the alpha channel of the people as a mask. That way, if you want to change the opacity of the faded people, you don't need to rerender anything, just a 1 minute tweak in comp.

[sprayer]

you need rayswitch material
http://imagizer.imageshack.com/img921/6742/Gsqu1W.jpg

[James]

If you want them to be in the render it would be easier to use 2d people set to always face the camera (i.e how things work by default in sketchup).  Give them a bit of thickness so that the materials behave how you want.

The sketchup warehouse would be the best place to find the 2d people as well.

https://3dwarehouse.sketchup.com/model/ud6e26057-e163-44d4-afee-b64eec499988/Face-Me-people-in-50-opacity-Black

[Artcrimes147]

Njen, you are right, this is a fantastic way to do it ~ was hoping for an alternative, if for nothing else in the end than just to satisfy my curiosity for the problem at hand!

sprayer, I was thinking there was something in the Rayswitch Mat that could work, and this looks very promising, but is there something I am missing? I can't seem to get it to render the way you're showing it...

James, I totally hear you, but unfortunately all of the people will also be animated and it would be central to the style of the animation not to have them be billboards.