cel shading

Hi all - new to SL and it's awesome!!!

I tried to use the search on the forum and didn't get any results.

Anybody have any good cel shading tutorials?

Thanks!!!!

The easiest way to make an "outline" around a prim is to make a slightly larger prim encompassing it, make that prim hollow and the inner surface black, then the outer surface invisible.

I sent you an example and the accompanying texture in-world.

I've used this method before, works great; but out of interest, is there another way?

Can anyone post a picture of the end result? I'm confused at to what cel shading means.

tks.

ahhh i see... looks like something good to shoot at! Thanks for the tip!

Cel-shading is a great way to bring a 2-d comic-book or cartoon "vision" into the 3-d world. Only downside is that it seems to requre at a minimum twice as many prims to achieve the effect. It also seems to favor shapes that have as few edges as possible.

Questions for the experienced cel-shaders out there:

1. I tried making a cel-shaded cube, but in order to get it looking "right", I wound up having to make 1 prim for each face, for both the "inner" and "outer" cube. 12 prims, for a single cube! Any shortcuts or hints on cel-shading cubish shapes?

2. What about cel-shading an avatar? I know it can be done by attaching cel-shaded objects to an avater, basically making a cel-shaded Snoopy, or Batz Maru or whatever. What if I wanted to cel-shade a basic avatar shape? Is there any combination of photoshopped clothing, textures and tattoos that could give my avatar this effect? Is it possible to do som exotic texturing to objects which woudl surround my avatar, but be mostly phantom/invisible, leaving only that visible "catoonist's line" around my avatar's body, as seen from any angle?

No.

Not so fast. I've seen tons of cel-shaded avatars. Of course, they need to have full body attachments (i.e. Snoopy). Look great, too

Yes, and he was asking about non-attachment cel-shaded avatars. Something built into baked clothing.

Ergo: No.

Thank you so much Catherine!
I never realized it was done with objects and thought it was done with textures in photoshop or something like that.

I had so much fun this weekend playing with this. I made objects with multiple cel outlines.

I am wondering now if that is how real Cel-Shading is done because it is interesting. Or even "toon-shading" which was used in Legend of Zelda: The Wind Waker where not everything had a thick black line around it but still had that cartoon look.

There are lots of tutorials and white papers about it on various web sites.

Let me break it down as succinctly as possible Some of this involves knowing about how 3D graphics work in general.

There are some terms that you have to understand to be able to understand what "Cel-Shading" really is. I prefer the term "cartoon shaded" because it's more accurate.

There are 2 parts to a cartoon-shaded image that make it different than a realistically shaded image. You can only do one of those things in SL. In the animated movie world, artists create animations by drawing with black ink on clear sheets of plastic. They then color the images by turning the sheets over and painting the back sides. This proces exteremly smooth coloration without the usual artifacts that painting causes (no texturing, for example). This complete image is known as a "cel". In order to save time, most animators don't realistally shade a moving object. It takes too much time. Instead, they usually draw one or two levels of shading, and occasionally draw in a layer of highlights.

So the totality of this image, with the inking lines and the sharp gradiations in shading becomes what we think of as cel-shading or cartoon shading.

There are easy ways to emulate this effect on 3D graphcs cards. The first is to draw the inking lines by drawing outlimes around all the shapes that make up a 3D object. To make the lines only appear around the edges, you offset the lines so that they are placed further behind in the Z-buffer. (this is how the rendering engine knows whether parts of an objecg are in front of or behind each other). you can alos simulate the effect by a technique known as "culling". Essentially, the rendering engine knows which way the faces should be visible from. It draws limes aroudm the faces that are rear-facing only. This causes the borders of the object go be "inked", but not the front. You can add accent lines by simply drawing lines on the surface of the object as textures or as separate 3D pieces.

Now the second part of true cel-shading is the *shading*. This part is really complicated, and took me a while to grasp. Essentially, you use a texture (just like the ones we use in SL for other objects) that only has black and white in it. This texture is laid on top of the object as an extra layer. In the 3D world, we call this multi-texturing. To make this shading respond to the object's position relative to the lighting in the room, we have to play a trick in the program and move the texture coordinates around to map the texure based on the relative direction of each point on the object.

the whole process isn't horribly complicated, but it IS a little more complex than standard 3D shading. Because you have to manually calculate texture coordinates for every object, the frame rate tends to drop. On the bright side, you don't need lighting (no pun intended), so that can help.

In my experiments, I lose about 1/3 to 1/2 of my frame rate by cel-shading. But since I'm intending to use this technique to render still images, it's not really a problem.