There's plenty of work being done right now using Shaders for Cell Shading effects -flattening 3d models so they look like animation cells. But I was wondering, has any work been done on a 'true' cell based rendering engine? To clarify: part of the problem I see with Cell Shading is you take a 3d model and flatten it; whereas actual traditional animation is drawn by an artist in 2d and thus is able to take advantage of stylization which is not necesarially possible or spatially consistent in 3d. I'm fairly sure that actual animation studios use CAD assist with tweening animation cells nowadays; does that same system exist anyplace for realtime tweening/morphing of 'cell models' for games?

As far as I know no one "flattens" 3D models to make them look 2D. When I've implemented it I just rendered with a select few tones on the model, so they have that 3D, but drawn look to them. You could do it without lighting at all if you really wanted to, giving simple single colours with no shade on them at all.

Another thing I'd done is draw the outline of the model as well. Nehe has a good tutorial on this for OpenGL, but the same principle applies when using another API.

Do you have any pictures of the effects you are actually trying to achieve? I'm guessing you mean everything is actually in 2D, if thats the case you should be able to tween cells ( well, 'models' ) using vertex key framing, even skeletal animation if you want to take it the step further. Although I can't really give you much more help/info, since I've only really done cel shading with 3D models to give a slightly cartoony look, but I don't touch the models geometry in doing this.

About the only game that springs to mind is Paper Mario for the gamecube, which uses hand-drawn sprites which bend and distort to give a more fluid feel than just switching between images.

However I don't think traditional animation studios actually use CAD or similar to tween frames. I thought it was largely done by outsourcing the inbetween frames to Korean animators... (Hence "it's the death of animation" outcry).

Sorry, when I said that current technique is to 'flatten' 3d models
I didn't mean literally projecting the vertices to a plane.
I meant flattening of colors shading to a few select tones.

Actually this is entirely theory and discussion, I'm not building anything at the moment.
But as to what I was hoping to see... It is usually fairly obvious the difference between a cell shaded animation and an actual 2d animation; which I see as a flaw inherent in the current approach. I was thinking that you really need to start out with a 2d based cell rendering engine, not by special shading of a 3d model.

Wondering if any work has been done to move in this direction, because if anyone does I suspect it would look superior...


as to traditional animation techniques (for non-games) the outsource of tweening to Korea statement is mostly true, but there are exceptions
for example the anime 'Fruits Basket' was entirely 'drawn' in software to reduce production cost -no physical cells exist (they stated on the dvd extras, but neglect the specifics)
also the American cartoon 'South Park' is created entirely in a Flash-like software by just a few people (crude example since the quality is inentionally bad, but it is going in the direction i refer to)

to reiterate, I'm wishing that Toon Rendering can be made indistinguishable from real animation by borrowing the same techniques; which seems to be becoming more plausible nowadays as some animation is starting to use software assist and the two fields might have a chance of converging...

So... you're suggesting that cel-shading should be done in 2D by actual animators? No 3D models at all? Isn't that just plain 2D animation?

Quote: Original post by haphazardlynamed
as to traditional animation techniques (for non-games) the outsource of tweening to Korea statement is mostly true, but there are exceptions
for example the anime 'Fruits Basket' was entirely 'drawn' in software to reduce production cost -no physical cells exist (they stated on the dvd extras, but neglect the specifics)

Lots of animation houses uses 'digital ink and paint' (Disney have been doing it for years IIRC) where physical cels don't exist - but while the content might be digitised there isn't any tweening or interpolation going on. It's still basic flipbook animation.

I agree that hand drawn does have a certain flair - but thats only because the artists are specifically working with one particular view and one particular frame at a time. The whole point of toon/cel shading is to be able to view cartoon style visuals but with the advantages of 3d, i.e. the ability to view it from any angle and any position. The two are mutually incompatible.

The only way would be to replace an animated 3d model with a whole heap of images drawn from every angle for every animation frame. Not only is that *far* too much work for anyone to realistically create, but it would consume far too much memory (and I doubt the results would be terribly good either, as you'd get all sorts of snapping/popping artifacts).

Maybe if you actually proposed some kind of approach/solution rather than just vauge, handwave-y "but it looks better in 2d" statements?

Quote: Original post by OrangyTang
Maybe if you actually proposed some kind of approach/solution rather than just vauge, handwave-y "but it looks better in 2d" statements?

Well I was hoping to hear some of Your suggestions and Existing Work on this subject... I'm not trying to tout this as my own concept; I was actually hoping to hear that it already exists and I just haven't found the paper yet...


Uhh, if I had to approach this on my own though I'd probably think:

Maybe a vector art representation for keyframe cells
with specific splines from one keyframe to another associated(by the artist) so that inbetween frames can be morphed in a controlled manner at runtime?
highly artist dependant, but you're not hand-drawing a cell for every single angle, and you're not using up insane memory space