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Cel Shading

Posted: Sat Oct 19, 2002 12:04 am
by heavycat
A while back we did some experiments with a cel-shading texture in Blender, and while the results were interesting, we're wondering if there is a more general purpose capability available:

Is it possible to adjust lighting in Blender such that instead of a gradient shading model, there is a two level model: 1) the texture color 2) A slightly darker shade of the texture color? I know there is a Lightwave plug-in that will do this.

Is this possible with the Python scripting, or is it something that has to be adjusted within Blender itself? This would be massively useful for a variety of projects. Any help or ideas would be appreciated.

Posted: Sat Oct 19, 2002 6:02 pm
by beatabix
not possible in python, now and for a long time in the future, i would presume.

but that doesn't matter, because the source is open now. i remember seeing a BMRT surface shader somewhere that worked as a very basic toon shader, that might be a good start to look for ideas.

cel shading is alot more complicated than it looks, however, especially when it comes to edging. maybe some like-minded people could get together and do some research, or even try and come up with a new method of creating cel shaded images.

BEAT

its a little closer then you think

Posted: Wed Oct 30, 2002 2:17 am
by Sutabi
I've messed with the texture with blender a lot to try to get a decent toon style shading.

I think it would be easier to just imply shadless to no recive light but still be able to cast shadows. As well as material to be able to reflect base apon a light(s).

So then you could just create a blend texture and refine it to display sharp blend shading to look like toon shading then apply it to a simple material and adjusting the Col to some thing decent to match the color you wish. As well as selecting the shadless button. Although you can already reflect material based apon an object it cant really cast a shadow with the shadless feature on.

Posted: Wed Oct 30, 2002 4:10 pm
by Dani
I wrote a french tutorial three months ago about cel shading, shadow casting and animation.
Uses textures.
Do you want me to translate it?
I'll can do it in english and I can try in spanish (no garantees :)

Dani

Posted: Thu Oct 31, 2002 12:22 am
by beatabix
here's a nice collection of resources:

http://www.red3d.com/cwr/npr/

i'm already trawling through this. so many pdfs, it'll take me days to download on dialup.

some of these could even be worked into the realtime engine.

BEAT

Posted: Fri Nov 08, 2002 1:06 am
by jeotero
i can do a revision in the spanish version :)

Posted: Fri Nov 08, 2002 3:51 am
by kino
Hi all
Ciao Dani :)

here is my italian version
Blender Cel shading by Dani

google translate seem the better :roll:
Blender Italian Blender Cel shading by Dani google translate

no time to fix the code e' read as is , necessita' as need

hope can help, if someone do a better translation please send me
i pleased to include on kino3d

Ciao
Kino

Posted: Fri Nov 08, 2002 9:26 pm
by Dani
Hi guys!

tomorrow I'll fetch the code from the translated to english version and correct it. Then I'll send it back to you.

Joetero: I'd appreciate a lot your help, for I'm kind of over booked lately.
You need which language to start from?

Dani

Posted: Fri Nov 08, 2002 11:50 pm
by Dani
Hello!

Finished the to-english translation... shood be up soon.

I found several ways to improve this technique, make it easier, but I'm not sure if it's worth a tut, with all of blender's evolutions.
I also found a limit: the technique works when the camera is the same side the tracked-lamp is regarding the toon object. If it's the opposite side you'll have problems.
I.E. : you have a toon caracter with camera and lamp facing it >> all will render fine.
Now you put the camera behind the caracter so it looks at it's back: here you'll have shading problems.
This can be prevented by moving the lamp too: needs preparation.

Oh! something I forgot in the original tut: you can play with the envmap's "filter" value to change to sharpness of the effect

There are lots of ways to play with this shading technique, i even manage some refraction. (quite complicated and rather slow). Anyway, have a look (by the way, the original ice cube isn't mine... if the author recognizes his work... tell me!):

http://dani1.chez.tiscali.fr/compiled.html
http://dani1.chez.tiscali.fr/sequence.html

have fun!

Dani

Posted: Mon Nov 11, 2002 12:13 am
by heavycat
Sorry folks. I set it to notify by e-mail if there were replies, but I didn't get any e-mails. grrrr..

Thanks very much for the new information. It would be particularly cool if "toon shading" were available in Blender, because we just produced our first (of many) 3D anime models. 8)

Posted: Tue Nov 12, 2002 4:22 pm
by kino
Hi
here the english version from Dani

Cell shading English version

any suggestion and or contribue are appreciated

Ciao

kino