AOVs in VEX shaders

[j00ey]

Hi

 

This is probably a dumb question, and makes me realise how little I really know about SHOPs.

 

I have a scene with various shaders that I built myself with material shader builder nodes and I'm exporting a few AOVs inside. I just attached a constant shader to something though and realised I have no idea how to get it to output my additional image planes, and also I don't really know what this type of shader is and why it has a Surface Shader output... The only thing I can attach it to seems to be an Output Shaders node but I can't figure out what else I can plug into that to get my AOVs.

 

Does anyone have a couple of minutes to explain A - what they are [the shaders with the stripy baseball icon - VEX shaders?] and B -how to get them to write extra planes? I know I can go in the type properties and see the code but I'm uncertain whether that's the way to go about it or if I'm missing something obvious...

 

I hope someone can enlighten me...

[altbighead]

It's a big subject but luckily you can thank Peter Quint.

https://sites.google.com/site/pqhoudinitutorial/home/videos-on-the-basics-1

Basics : Surface Shader I on Vimeo

Basics : Surface Shader II on Vimeo

Basics : Surface Shader III on Vimeo

Basics : Surface Shader IV on Vimeo

Materials 11 I

Edited March 18, 2015 by altbighead

[j00ey]

Hi

 

Thanks for the reply. Good old Peter Quint!

 

I had a quick scrub through those and I may be missing something but they appear to be about VOP materials, it's the ones that you can't dive inside and edit that I'm a bit confused about, see pic. I know how to edit VOPs and get my AOVs out of there but how would I go about getting say an ID pass out of something with Gingham Checks applied?

[danylyon]

Hi

 

Simply define the variable as export in the surface shader and assign a value. For example:

#pragma hint uv hidden
#pragma hint Cd hidden
#pragma hint myAOV hidden

surface mySurfaceVEX(
// IMPORTS
vector  uv = 0;
vector  Cd = 0;

// PARAMETERS
float   ior_i = 1;

// EXPORTS
export vector myAOV = 0;)
{
myAOV = normalize(N);
}

The #pragma's are "cosmetic", this tells Houdini not to show those variables as parameters.

[j00ey]

Thanks Dany. I will look into that.

 

By the way I haven't had chance to try your layered PBR shader on my new machine yet in case that clears up the errors. I'll do that soon as I get chance, after the weekend probably.