Cube In Cell-Shaded Style?

by sinware on 01/24/2005 08:36, 11 messages, last message: 02/03/2005 16:21, 1877 views, last view: 04/29/2024 10:29

Hey there everyone, I was wondering, wouldn't it be cool to have Cell-Shaded models/weapons and maybe even the "world" (textures, etc)

I know models can be made cell-shaded somehow, seen it working on Half Life, anyone nkow how to do this or wanna put time in finding it out?

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#1: ..

by tentus on 01/24/2005 15:45

Cell shading would probably require a lot of smplified skins, a heavily tweaked lighting system, and probably a number of subtle changes everywhere else. Don't let my doubts stop you though, it'd be fun to look at.

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#2: Its doable.

by Pxtl on 01/24/2005 18:48

I know how it works. There are two components - lighting isn't really a worry.

1) Outlined skins. This one's obvious - hard black lines everywhere. Optionally, you can use flat fills and fullbright to make a full "disney" cartoon effect, but for a nice comic-book compromise then black lines are the only skin change necessary.

2) Flipped models. Here's the trick: You take each model, and edit the model as follows:
a) clone the model on the spot.
b) invert the normals of the faces of the clone
c) push all the vertices outwards (or backwards, depending on how you look at it) by a value equal to the thickness of the black lines in the skins.
d) skin the clone in all black. You'll have to make a small black section in your skin and then stretch it to cover your whole outline clone.

The end result is that you've created a black shell around your model with its faces facing inwards. Since the inward faces effectively means only the backfaces can be seen, then the model has a black silhouette behind it at all times. This produces an outlining effect around all of the models.

Its a horribly inefficient way to do it, producing huge polycounts, flimmering, and other problems even when done well. But it works. That's the way you do it pre-shaders.

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#3: ..

by makkE on 01/25/2005 00:35

Are you sure cube will render backfaces black? As far as I know they are transparent in Cube.. .

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#4: You misunderstand.

by Pxtl on 01/25/2005 01:45

The backfaces have to be transparent - that's what you're looking at. You see the backfaces (which you don't see), then the model, then the inward-facing shell behind the model. That shell is coloured black.

You see, the shell is the model itself, but with normals reversed so you only see the part that is facing inwards, which is the part behind the model you're looking at. You colour the shell black so it provides a black outline around the edge of your model.

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#5: Re: ..

by tentus on 01/25/2005 01:56, refers to #3

You misunderstood him. He proposes to create a totally sepeate model with a black skin, whith the face normals flipped. It's really easy to do in q2modeller. This model will have to be slightly larger than the original to be seen (not at all easy in q2modeller, I've tried). They're rendered at the same place, so that you look at the original model and then see the new one as if it was behind it, outlining it. Take a look at the quad in DI or the teleport in LoZ to see examples of this.

But as pxtl said, this would be terribly, terribly inefficient. It wouldn't even properly do the job, b/c you would probably want to make outlines between surfaces in the world. I assumed that the cel shading in question would be along the same lines as Wind Waker, which is one of the very few celshaded games I've enjoyed visually.

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#6: ..

by makkE on 01/25/2005 03:10

Ahh :) Tnx now I get it :)
Well editing the skins would be more efficient I guess.
I am not a fan of that style.. think it´d look odd and bland.

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#7: As I understand it....

by Pxtl on 01/25/2005 03:47

I've heard its pretty easy to do in 3DS-MAX, or so I've heard. Pushing the vertices along their normals is a simple operation there. There are two Quake 3 models that I know of, created in this style: Snoopy, and a generic female whose name escapes me. Take a look at Polycount.com for Snoopy and you'll see a good example to play with.

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#8: Re: ..

by dcp on 01/25/2005 03:58, refers to #5

ever played XIII ?

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#9: Re: As I understand it....

by tentus on 01/25/2005 23:18, refers to #7

What makes it hard is that it must be done for all 197 to 199 frames (depends on whether you have skinning frame etc); individually for most modelling programs. Perhaps in MAX, which has the very interesting timeline-based interface, it would be easy, but such a project would still take considerable effort. I'll look into the resizing question in MAX (my school has a trial version of max available for the graphic design students like me to use).

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#10: Re: As I understand it....

by desplesda on 02/03/2005 10:53, refers to #9

I'm not sure that that's really cel shading. Would there be any way to implement the sort of shading found in XIII?

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#11: Re: As I understand it....

by Pxtl on 02/03/2005 16:21, refers to #10

A metric assload of work. Anything up to Quake 3 games will be using the pushed-silhouette method of outlining. Newer games use shaders, which would be a monstrous amount of labour to implement into the Cube engine, while you can do the pushed-silhouette method right now.

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