Save out all LightMix Layers only (with adjustments made)

[ChrisLane]

Hi Chaos / Everyone,

First off - we absolutely love the new LightMix feature, it has saved us so much time for rendering / animating lights!

Its probably best that I explain the use case as this would make sense as to the type of feature we think would be useful.

One of the main services we provide for our Lighting clients is whats called a LightSIM, where by the user / stakeholder can control the lighting in the scene and decide on different lighting presets when it comes to commissioning. See video below;

https://vimeo.com/164715976


This requires us to re-create the space in 3D and render each light as a separate layers in Vray, then add interactivity using Unity so that the user can dim or switch lights on / off with switches and sliders. For dimming lights, we traditionally just rendered one image and then the slider in the interactive would just control the layers opacity, however this would cause visual issues, as lights in reality don't dim like this and it would make the visual impression look washed out towards the lower dimming percentages.

What we realised we had to do was to render the lights in an animation from 100% to 0% so that we could see the gradual reduction in light output to the source that happens in reality.

When LightMix was released and we realised that we could do all this in the frame buffer it was like a 'hala lu ya' moment as we knew at that point we wouldn't have to render out 100s of images! Unfortunately there is no way to save out all the LightMix layers with the 5% increments we would require quickly! its very much a manual process where by we have to adjust the overall percentage, and then turn all the lights on one at a time and save them out one at a time to get the 20 frames we need per light fitting.

Do you think that it would be possible to have a button that would allow users to just save out all the LightMix layers with any changes made to the outputs / colour etc in the VFB??

Currently the save buttons only allow the user to save all the render elements separately, which doesn't include any changes made to the light layers in the VFB via LightMix.

If we have a scene with 15 - 20 different sets of light fittings which is quite common for us, it can take half a day just to manually save out the images we need for dimming.

Apologise if this is quite lengthy, I hope it all makes sense - any help with this would be pretty ace though!

Thank you!

Chris

[^Lele^]

Oh, that is most definitely something which should be scriptable.
Whether it's already a specific option or not, and how broad the capabilities are, i'm not sure of right now, but i'll be investigating this asap, and perhaps provide you with a skeleton scripted tool to execute the basics.

EDIT: While you wait for me, take a look here for a small guide to the basics, you may well be able to find a way to do what you need by yourself.

[ChrisLane]

Hi Lele - Thanks for getting back to me!

If you could help that would be ace - unfortunately i'm not the best when it comes to scripting and have no idea where i would start with something like this.

All we it to do is save each LightMix layer separately with any alterations to colour and output made in the VFB... is that something easy to do via a script?

[^Lele^]

I mean saving each LM layer as is, in solo mode, into an exr.

A word of warning, though: you mentioned you didn't get the right light decay when doing the post blending in Unity.
The method *should* work perfectly fine if the LM layers are added, 100% opacity, and their value is changed from 0.0 (black) to 1.0 (the original intensity) or higher.
This way, so long as you're using a floating point buffer/set of images, the maths is identical to using the light's multiplier and color swatches.

P.s.: there's a job section in the forums to cater for these kind of needs.
Maybe there's a scripter looking for work, and you'd surely save a ton of time if you got a tool which did precisely what you need in a few seconds rather than a day.
Regardless of what i may come up with, you could do worse than investigating this avenue.