So, assuming we''re building something with cell shaded graphics, how would we go about making an outdoor (grass and hill) environment that the user can actually interact with. The primary concern I have is that cell shaded graphics rely on relatively flat colors and dark lines which are only applied to edges where one polygon is visible and the other is not. With terrain this doesn''t seem to work, since you couldn''t see the edge of hills, and thus you could really only see the tops of everything. Any ideas on how to make the terrain distinct enough the the user can meanfully navigate it?

There are many ways I think.

In some japanese movies, the background art is just awesome. But I guess doing that quality in realtime is out of the question.

Mostly, when you see landscapes in cartoons, you see the far-away mountains, some green, big hills just below, then the woods. And after that you don't see much more terrain.

The shading is pretty special. I don't know how to animate it, but the shadows are sketched with crossed lines or are furiously dotted. So, on the terrain, you could add some controlled noise on the darker sides of the hills or add a fading overlayed criss-cross texture. Also, depending on the lighting strength, you can use different shading-techniques.

It depends a lot on the type of game you're doing. An adventure game would look great with cel-shaded objects in very detailed environments, but in an FPS, it'd look better if pretty much everything was cel-shaded.
I had a go at the XIII-demo yesterday, and the detailed environments killed the whole idea behind cel-shading. Just looked like they had put some lazy effect on the characters and that's it. Pretty sluggish too, but lots better than Uneal 2 :D I like the potential stealth-games, so now I got another game to wait for...

EDIT: Some syntax errors

[edited by - coelurus on August 14, 2003 4:25:59 AM]

[Off-topic]
Isn't it 'Cel' insteading 'Cell'?
[/Off-topic]

You could do a diffuse color, and add light or drker color shortlines together, randomly on a few spots.

0 = nothing
1 = grass

000000000000
000100000010
101000111000
001011001000
010001011100

Also add some ovals of lighter green.
You can study some cartoons and see what they did.


.lick


[edited by - Pipo DeClown on August 14, 2003 5:16:05 AM]

It''s definitely "cel". The term comes from traditional hand drawn animation were the characters were drawn on transparent cels to keep them separate from the static background image. Anyway, depending on the style of your game you could either go with simple textures and some sort of NPR lighting or with something more complex. It''s fairly easy to either create lighting with distinct lighting levels (just a couple maybe three or so) or transform the lighting into some form of hatching in real time.The light levels approach is dead easy just look up N.L in a 1d texture with the levels (you might want to us enearest filtering). Real time hatching is more complex but still not terribly so.

quote:Original post by OrangyTang
What kind of viewpoint for the game? Something battlezone style and close to the ground? Or more Warcraft 3 style and a decent distance above the ground?

Think about a buggy racing game. Your viewing position is close to the ground, and you need to be able to tell where changes in the terrain height are (both close and far). In tradition cartoons the backgrounds are normally drawn differently. While the characters are "cel shaded" the backgrounds are normally more painted with textures and detail (detail really depends on budget). I just don''t know how well either normal computer terrain would look with cel shaded objects or if it would be possible to create that "painted" look (or if there is a way to do the more simple shaded approach). For instance the lego demo has a scene (boat scene) where there are cel shaded hills. However those are far away, and don''t really convey useful information (the hills are there, but you can''t tell where they begin)