KTOA : how to write custom AOVS from a shader

[jondiyolahe]

Hello,

How do you write custom AOVS.the input is multiple alsurface with custom massk and look, and i want to output that as an multiple aovs ?*

i tried multiple things without success

[Mike_Farnsworth · Accepted solution]

I assume this is KtoA 1.1.x? There is a built-in set of shaders: aov_write_float, aov_write_int, aov_write_rgb. Create one of those, and take the output of your other shaders (alSurface or whichever you want the output from) and plug it into the "passthrough" parameter. Then, you take the actual value you want to write to the AOV and plug it into the "input" parameter.

On the aov write shader make sure to set the name of the AOV you want.

To actually capture the AOV, you will also need to create an ArnoldOutputChannelDefine node that specifies the AOV as the channel. Set a name there as well, and then create a RenderOutputDefine node that uses that named channel.

[jondiyolahe]

Thank you Mike, this is working as magic.

Thank you

[JWRodegher]

Hi Mike, is there a way to use several aov_writes for the same shader? What I need is a set of masks that output only from one shader (characters eyes in this case), but it seems that if I input a aov_write to the passthrough of another aov_write, it doesn't work (I lose all connection to the shader btw).

So, let's say, I want to output RGB masks for iris/pupil/sclera, plus an AO pass, plus a sampler info, how should I go about that?

Thanks in advance for any insight you might offer.

Cheers.

[JWRodegher]

Actually, scratch that. The error was a duplicated name that made the whole thing crash. It's working perfectly fine now.

Cheers.