Model Outline Rendering

[matticus01]

Ok this admittedly may be a really stupid noob question....

but does anyone know how to render out a model so an outline is presented around the model in a sort of cartoon stylised fashion?

the best example I can think of is from the newest prince of persia...
http://xbox360media.ign.com/xbox360/image/article/877/877054/prince-of-persia-20080527114815313_640w.jpg
howd they do that?!

if theres an answer to suit 3ds max or maya thatd be awesome!

cheers guys! :thumb:

[sinz]

The answer to this would be benefical to many, hope someone can shed some light.

No question is dumb!

[Maph]

Realtime or software rendering?

Realtime, there's several techniques like duplicated and inverted geometry set to a solid black color; advanced shader effects, you name it.
Neox made a wonderfull shader in UEd 3 for this effect. I suggest you check it out by searching for his airborn thread.

Software -> your standard toon style rendering. :)

[cookepuss]

There are several ways to go about this. Some old school. Some new school.

A modern solution might be to create a simple shader. A tight gradient Fresnel shader overlayed to the final textured model would give you the illusion of a toon outline. This would be very GPU friendly and probably the most efficient method.

Other older, non-accelerated methods might...

- Include running it as a in-game post effect that gets dropped on right before final frame output
- Childing a secondary outline mesh to the core mesh. I've seen a number of ways to do this. One such method is to attach a slightly larger version of your character mesh, but painted solid black and with inverted normals. Why would this work? With backface culling, the inverted faces that would normally obfuscate the character's front wouldn't get rendered and only the ones that sit behind the character would. It's an old school toon rendering trick. The downside is the penalty paid due to extra geo, which might not be such a big deal if you're going with a toony look. Most toony games don't require hyper detail anyway.

Anyway, those are a couple of ideas. This is not a new problem. Just google it.

[usersen]

In Maya you can do it if you rendering with mental ray

Create a new material
Go into its presets (little arrow beside the material name)
Under mental ray > Contours check the Enable Contour Rendering box
You can select your color and width of the line below

Got to your mental ray render settings
go to Contours and check Enable Contour Rendering box
Under Draw Contours select the type you want, you want to have the around silhouette (coverage) box ticked and only that box for an outline.

render

You should end up with something like this:

[cookepuss]

I'm guessing that he's asking about in-game because doing this inside of your 3D app is easy. Almost too easy. At this point, just about every 3D app has this sort of feature. In C4D, I'd probably use the functionality of extremely flexible Sketch&Toon module or the built-in cel rendering feature of the native renderer.