I've heard about Cel-Shading, but.......

[Anchel]

.......what is it??
/me prepares for the upcoming laughs

[Anchel]

I know that LoZ for Gamecube uses Cel-Shading graphics (like my avatar) but I don't really know what the difference is.....

[zorbid]

Cell shading is a way of producing cartoon-like gfx. It takes ~standard 3d gfx, then calculate how to make it look as if it had been drawn by a human hand.

[Jaz]

It's wank.

[Tri-Force]

how did i know that was coming

[RatTrap]

Cel shading:.. why it's called that is bcoz it's what they draw the cartoons in.. these cellulosa based see thru panels are used on any cartoon that isn't made by computers.. some cartoons are a mix of both though..

the way it works:.. you take a 3d world with everything you want in it, disable lighting and disable blending.. this gives us a 2d scene.. what we do next is use a special type of lighting texture map..

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the one above would be a normal shade blending light map.. it's got a variety of shades.. wich would give a 3d object all it's diferent colors.. this is not the way 3d is donne though.. but i'm showing you this one so you can compare..

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this one above would be the "cel shading" texture map.. lets call it "1D cellighting map" (the funny thing is.. i don't know what they call this map bcoz it's been called diferent all over the world.. some ppl call it 'sharp lighting map' some call it 'cell lighting' and i've seen a multitude of names for it).... think of the "=" in the "maps" i created above as pixels instead.. they are gray coz they are later blended with the color of each object.. so they are gray just to shade the end result..

the rendering engine as i understand it must carrie a value for the vertex/spline facing the light(s)/camera that enables the 1d cellighting map to blend itself into the object that is being rendered.. if you've seen an anime or a cartoon.. wich i hope you have :p.. you know that cartoons allways have like 2-3 shades of each color that they have on them.. this map makes it look just like cartoons by using it's 1D lighting on the object.. i think you know what i mean now.. this is the way it's donne.. there are alot of engines now that come with a multitude of precompiled ways of creating this kind of effect.. but for me who only do things in 3dmax.. and don't own the cel shading plugins.. well.. i'm forced to do it the good old manual way .. the outlines btw are usually not donne with the help of the "1D cellighting map".. but they are modeled in a special way so it will show an outline.. some renderers create an echo object (copy of the celshaded object).. wich it gives a 100% black wireframe texture.. and look for the lines that cut the smoothnes in the object.. and makes these lines the outlines of the objects.. there's other ways but those are abit to dificult to explain.. i'm not sure i understand them fully myself ..

[pj64er]

that was a good read.

i once had a little program which showed a 3d (u can rotate/pan/zoom) cel shaded model of sonic. if i find it ill attach it for ya.

[Jaz]

Originally posted by Tri-Force
how did i know that was coming

Because I'm that predictable.

[Reznor007]

This might prove helpful...

How to use Cel-shading in OpenGL.

[RatTrap]

if you wanna use it in OpenGL you'll probably need to go read a more advanced tutorial.. i was trying to be as clear and simple as possible on my explanation above.. i didn't really explain how it works with more than 1 light.. well it's pretty simple really but also texture coordinating is kinda trycky.. eather way the whole cel-shade look can be created in more than a few diferent ways it seems.. i myself have only used an older way of doing it.. i'm sure there's better more efficient ways to do it for OpenGL.. i'd sudgest searching for tutorials on the subject.. when i looked for it long time ago there wasn't many out there but now that it's becoming alot more popular you should be able to find alot more ..