I’m a bit confused regarding Global illumination in Houdini. I have read many GI topics, but there one thing I hope someone will clarify to me.

Is the GI Light and Diffuse Limit in Mantra two different tools for the same thing, or is the Diffuse limit in Mantra a setting for the GI Light?

Example:
Is it possible to use the GI Light, with the Diffuse Limit set to 0?
Is it possible to set the Diffuse Limit to 2 without using the GI Light at all?

Reco

GI emit photons from light pre-rendering. you can think photons as many thousands of little lights. They bounce/refrection in the scene to fake global illumination.
In some situations such as caustics use GI is faster. Diffuse limit is that the pbr renderer trace light with brdf shader.
So,you can think gi is a light tech, and diffuse limit is a render tech.

Thank you Jerry

Than it is two separate options and technology, doing the same thing.

I’m coming from Lightwave, and used to create a background, activate Global illumination, chose GI method (Monte Carlo/Final Gather) and adjust the necessary settings.

So I added a GI light in Houdini and thought it wouldn’t work unless the diffuse Limit was set to 1 or higher.

Thank you for clarifying.

Reco