hi
i want to render diffuse passes for each light,so I add extra image plane in mantra and use this setting.

but the rendered image is very funny~

how to deal with it?
thanks

Looks like buggy behaviour. I tried with a simlified scene here and had the same result. I've forwarded my scene to support.

–edit—

Sorry, no bugs just a lack of rtfm and on my side I assumed the in-built shaders were set up for this already.

Best regards,
Fabian

Most (if not all) of the Illumination loops inside shaders that ship with Houdini are built to accumulate all lights into a single value before exporting that value. This goes for terms like diffuse and specular for the most part.

This means that you'll have to write a custom illumination loop that outputs the value you are interested in “before” you sum it for this checkbox to work as expected.

simplified example.


illuminance(P, N, M_PI/2) {

/* other code … */

/* specular */
spec = specularBRDF(Nl, Nspec, V, rough); /* output this value */

totalillum += spec; /* sum all lights, then pass this to Cf eventually */

}


There should be a good amount of info around odforce on the subject. You can also look into the specularBRDF and diffuseBRDF functions as they can be used inside of an illuminance loop.

This is also in docs (scroll to the How To area):
http://www.sidefx.com/docs/houdini10.0/rendering/deeprasters [sidefx.com]