Make edges of a wall emanate a color

Hi, I'd like to know if it's possible for edges of a brush to have a different color or be in some way more distinguishable from its polygons.

For example, instead of this:
http://i.imgur.com/Bvgek.jpg

I'd like something like this:
http://i.imgur.com/tvTJu.jpg

Thanks

if it is for building stuff then i would just make a simple texture with a black square around the sides?

go to your content browser search for PostProcessChain'FX_HitEffects.UTPostProcess_PC' click on the AmbientOcclusionEffect Node. play around with the occlusion power. you can also change the occlusion color. It wont do what you want but you can tweak the effect you have posted in your first screenshot.

Thanks but as you said it's not quite it. I tried doing it with an outline but that didn't work so well either.

Need I just build the black lines with separate brushes? Tedious but oh well.

Do you want this only your BSP brushes, or on everything (like a Borderlands style effect)? To me it sounds like you want to do Sobel Edge Detection - which you can learn about here: Development Kit Gems: Sobel Edge Detection