View Full Version : Help for shading

02 February 2012, 11:20 PM
I've been wondering how necessary it is to use CgFX shaders for movies ... lately I've been researching and all I find is how to use it for video games, but I'm sure that is also used for film, but I do not know which way they use it. I'm on a project and I am in charge of the area of ​​shaders, I've been looking for the best way to make procedural texture for Maya, I wonder if you can share ways to make procedural texture. Pixar's looking is my "goal"

My main problem is I need to know if you really need to program shaders for better results, especially for procedural texture, and where can i find useful tutorials or books. Thanks! Sorry for my English, I'm from Mexico

03 March 2012, 12:55 AM
You don't need to use CGFX shaders at all really, ever. mental ray's shaders render much more accurately, realistically, and generally faster and more predictably.

For procedural shaders, you basically just make simple or complex shader trees using Maya's native procedurals. The "3D textures" such as Granite, Marble, etc. are pretty much all you need - you just have to layer them in Hypershade and link them up together! Start with a Granite base, and in the color slots plug in other fractal shaders, and even image maps when you like. It can be as complex or simple as you need it to be.

You don't have to program any shaders to get great results. I've never written a shader in my life, but made a career out of texturing/lighting/rendering, just the same!

03 March 2012, 12:39 PM
The difference between games and film is that Cg shaders are used in the final output in games. For film your final output is rendered files on disk - usually from a CPU renderer than a GPU one (putting fancy graphics cards on a render farm is still very expensive).

Interactive shading is definitely a useful feature, but usually not an essential component in getting an image rendered.

Graphics cards are more likely to be used for helping vfx simulations, but they are starting to help in final image rendering such as Weta's Pantaray. Both of these (I think) use GPGPU computing rather than CgFX.

There are many capable renderers out there which you should try out. If you feel there is a need for programmable shading then RenderMan obviously springs to mind. But also check out Mantra (very tightly tied to Houdini), Arnold and Mental Ray (not the easiest to write shaders for). I think Vray may have some options too - I'm not very familiar with it. I'm sure I've missed a few too.

It does help a lot to know in the background - you may want to get a copy of Texturing and Modelling - A Procedural Approach and/or Advanced RenderMan

But as has already been said most of the skill is getting good parameters, layering and good use of textures.


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03 March 2012, 12:39 PM
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