LightMix with multiple HDRi's - workflow for other render elements

[dwachonski]

Hello everyone,

I am writing with a strange question which I am truly stuck with for a few days of thinking. In my current case I have a scene of a building + some surroundings, therefore I have set 4 HDRi's, coronasun and some lights in the interior. In the interactive mode I have adjusted all the parameters of the lights so they are not overexposing the scene and now my question appears... When rendering the final scene. I am a bit puzzled about other render elements like reflections/refraction etc. After turning off other HDRi's and leaving one of them on, baking the lights to the scene, the reflection and other elements still show the lighting based on beauty, so with all the sources of light combined.

Does anyone have some effective workflow or tips how to work with this? Do you use the interactive lightmix only as a guidance to determine the light for your final scene and then just switch back to the single HDRi?
Or maybe shall I instead of putting the other hdri's off, just switch them to 0 intensity in the lightmix and then bake?

Thank you in advance for your replies!

[TomG]

LightMix doesn't affect the other render elements, which will always act to composite the Beauty rather than the LightMix. In general it's taken that if using LightMix, you won't then also be compositing and adjusting the composite in post, but using the final result from the LightMix element.

If you wanted the other render elements to work, I would envisage this kind of workflow - create scene, set up the various lightmixes and save them; save the lightmix passes as images just because; now go through each saved lightmix, use >scene, and save a new version of the scene, with that lightmix now baked in place, and render, to get the other render elements based on those light intensities (including HDRIs, with certain ones now disabled); repeat for each lightmix you created, creating a different version of the scene and saving it and rendering to get the render elements for that particular look.

Of course you could skip saving the scene multiple times, just load original scene, load lightmix, bake, render, save render elements, if you wanted to save the space of having multiple versions of the scene saved.

I think that would do what you are looking for, if I understand correctly!

[dwachonski]

Hi Tom,

thank you for the reply. I think you solved my problems more or less, however the thing is that when I adjust the lights in the lightmix (one hdri on, lights on, 4 hdris off *but not on zero intensity*) and then bake the lights into the scene, the beauty still shows the combination of each hdri at the same time and this is where my question begins. Because in that case the renderer should ignore the other hdri maps as well as coronasun and turn it off, but does not do that. So the option for me is just to switch later to single hdri map and render my scene but I'm just wondering if that is completely necessary, because it seems like a workaround.

The more logical thing would be that I choose the light sources, the others I keep unchecked, click >scene and then my beauty render only calculates these lights which were checked. Or does it work like this and I am doing something wrong if I don't see the desired effect?

[TomG]

If you have the multiple HDRIs connected through the "Multiple Maps (LightMix)" in the Scene tab of the Render Settings, then setting the intensity of one HDRI to zero and using >Scene will add a Corona Color Correct which sets the intensity of that HDRI to zero and so removes it from the Beauty pass. The Color Correct should in fact be added automatically for any intensity adjustments of an HDRI, so that it gets baked into the Beauty properly (so whether you increase it, decrease it, or set it to zero) - and you don't even need to manually add that color correct yourself :)

PS unchecking doesn't have any effect on the >Scene; even if unchecked, any changes to that light will still be baked to the scene (so if intensity is still 1, even if unchecked, it will still show in Beauty)