Renderman shader AOV

[Creepfree]

Hey

Output Variables got to be declared as "output <type> name" in the sahder's parameters block .
Then in Maya,navigate to the Default RiOptions field,and enter:

RiDisplayChannels "<type> name"

The last thing is to add your variable to the output,you can do this as you would normally do with any custom output.So navigate to the output->Create Ouput->Custom...->"name"

shader's and DisplayChannels' type and name got to be equal.

So it will look like this:

surface shaderName(...,output varying color myColor=(1,1,1);)
{

myColor=...

}
Then in the default RiOptions: RiDisplayChannels "color myColor"

And in the Create Ouput->Custom... the name will be "myColor"

Render to "IT",now your output has to appear under your primary pass.

[NealSct]

Hey Thanks Alex
The info you have given is very useful . I have tried to extract shadow channel
i have declare Output varying color __shadow = 0; in parameters block . For Air Renderer There is a function for extracting shadow channel ie. Diffuse ("shadow",__shadow) with this you get shadow channel separately But i can't find any such function for PRman i have also tried with lightsource function but it is also not working for me .
so can you please tell me if there is any function like this or any another way to extract shadow and unshadowed channel.

[Gravedigger]

hi!

in prman the standard workflow is to create an illuminance loop.inside the loop you can do things like:

lightsource("__nondiffuse", nondiffuse);
lightsource("__nonspecular", nonspec);
lightsource("_cl_noshadow", clnoshadow);
lightsource("_shadow", inshadow);


this seperates the lights contribution as needed and you can for example:

color cldiff = clnoshadow-Cl;
color diff = DiffuseColor*Nn.Ln;
OcclusionDirect = max(OcclusionDirect, inshadow);
DiffuseDirect += diff*clnoshadow;
DiffuseDirectShadow += diff*cldiff;

same for speculars. OcclusionDirect, DiffuseDirect and DiffuseDirectShadow are standard AOVs for renderman studio so when using this your shaders integrate nicely into maya

grs
Patrik

[rendermaniac]

What light shader are you using? The light shader needs to have corresponding parameters which are filled by the light shader. eg.


light shadowed_light(color light_color = 1;
uniform float intensity = 1;
string shdmap = "":
output color __shadow;
) {

__shadow = 0;

if (shdmap != "")
__shadow = shadow(Ps, shdmap);

illuminate(Ps) {
Cl = intensity * (light_color * (1 - __shadow));
}

}


Note that the __shadow output is output only so that you can write to it in the light shader - you can query any instance variable using lightsource(). You probably want it to be a colour so you can use coloured deep/raytraced shadows.

Simon

[Creepfree]

Yep,you don't have to write anything in this case.Explore embedded output's,everything is already done.

[NealSct]

Hello
Thanks to all for reply

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