Basketball shader

[amurayi]

Hi im plannin to implement a basketball shader,
Till now i have created the plastic material.
Please let me know how to go for it for displacements,Help me in coding as im a beginner.

Cheers
Vigneshwwar Viswanathan 

[joojaa]

What do you have now? Sounds like a school assignemnt to me.

[amurayi]

yeah it is. :D.. I have implemented a plastic shader and implemented a shadow procedurally.Please let me know how to proceed further.
Thank u 

[joojaa]

in that case check your local library and get a book on shading. Your actually supposed to work this out on your own.

[amurayi]

yeah but could you be of any help?can you tell how to apply bumps to the grooves

[amurayi]

can somebody help me out to create bumps for my basketball shader

[nowayfra]

the grooves...
Why dont use a texture for it?

edit: a file texture of course.

Do not have any glue about renderman coding but thats how i would do it with maya shaders. You eventually translate it to renderman.
You probably try to project four ramps at the basketball. two of them need to be set to "Type->Circular Ramp" the other two are Type U or V. The color entry positions of all the ramps should represent a thin white line on black back at the mid so that the output gives white circles at the circular ramp and white lines at the U and V ramps. Have a look at a basketball so you will know how to project all the ramps. You will need to put the outputs of all projections into a plusMinusAverage that is set to add. At some points the output of the plusMinusAverage will have a value of 2, thats bad for your network, so use a clamp node to get it back to a maximum of 1. Now invert the whole thing with a reverse node and plug the output wherever you need this groove pattern.
Just as inspiration.

[amurayi]

displacement basicDisp(float bumpheight=1;)
{
float myTexture=texture("bb.tdl");
P+=normalize(N)myTexturebumpheight;
N=calculatenormal(P);
}

here bb.tdl is the texture file.

Is this the way for creating the bumps?? 

[joojaa]

Well see the obvious reason i sent you to the library is that ALL OF THIS would have been exlained on 5-10 pages on shading. Since you are a student your also supposed to learn how to get the info without relying on in the future this is important. Thats the real life lesson here (yeah it sucks but thst the way it works). Indeed you could have googled for this too.

Anyway google for worley noise for example. should give you a pretty good basis to work on. (make the noise polar as opposed to cartesian)

as a general reading i also suggest

http://www.renderman.org/RMR/Publications/sig92.course21.pdf