backlit or halo lit signage in MR

[Matt McDonald]

Does anyone have any tips for rendering back lit or halo lit signage? I've tried applying a self illuminated material to the back faces of the sign. This works but I really have to crank up my FG Point density, ray count and interpolation to get something which is bright, tightly constrained to the letters and not smoky.

 

Suggestions?

 

Thanks everyone

Matt

[Camby1298]

Is this something you're willing to do in post instead? A Simple Matte pass of your signage will allow you to make a mask quicky in Photoshop or Aftereffects.

[Matt McDonald]

I hadn't thought of that. It might be the way to go. The building wall which features the signage is brightly lit by parking lot lights so any thing done in engine is going to have to be cranked way up to be visible.

[Justin Hunt]

Would cranking up the FG Quality and or FG/GI multipier (in the advanced Rendering Options tab of the Ach&Design shader) help?

 

jhv

[Bruce Hart]

An old school way is to render out your text isolated, get the alpha channel, gaussian blur it and then project this bitmap through a directional light unto the wall behind the sign with the text geometry excluded from the light.

[Matt McDonald]

thanks guys. I ended up having some pretty good success by raising my initial FG denisty and switching my interpolation method to Radius. The high initial FG point density was necessary to keep the light from blobbing out all over the rendering and the radius interpolation was necessary to keep MR from over interpolating from the sign to the wall behind (which made the front of the sign appear to be illuminated as well.

 

Thank you for all the suggestions.

Matt

[Joel Gray]

Try using a standard light with a negative multiplier, like this --> http://www.cgarchitect.com/resources/tutorials/smoke3d/tutorial9.asp I've done this in Vray before, haven't tried MentalRay yet. You can control how tight the shadow is (or light in this case) by adjusting the shadow map settings.