Light Include / Exclude / Multiplier: Rule Based System

[soulburn3d]

While reviewing the lighting in a shot or sequence, a director usually gets very specific about a lighting fix. They will say something like "I want you to reduce the strength of that light on that object." Achieving such a specific request is usually difficult, it frequently involves duplicating a light, setting up complex include / exclude lists that break the moment more objects are added to your scene, and possibly some compositing in layers to manage the complexity.

It would be nice if there was a more direct way to give the director what they asked for. That is why I'd like to see a Rule Based Include / Exclude / Multiplier system. This could be called "Light Interaction Rules", and be a tool that exists in Rendering Menu.

It would pop open a floater. In it, you can adjust these properties as rules. So for example, you could say...

- object Sphere01 is excluded (Shadow and Illumination) from light LightA
- object Sphere01 is included (Shadow and Illumination) in light LightA
- object Sphere03 doesn't recieve a shadow from light LightA
- object Sphere03 recieves a shadow from light LightA
- object Sphere03 doesn't recieve illumination from light LightA
- object Sphere03 recieves illumination from light LightA
- object Sphere04 recieved 30% illumination from light LightA
- object Sphere04 recieved 150% illumination from light LightA
- object Sphere04 recieved 150% illumination from selectionSet OfficeLights
- selectionSet MyBoxes is included (Shadow and Illumination) in light LightA
- layer MyLayer1 is included (Shadow and Illumination) in light LightA
- object Sphere07 doesn't cast a shadow on object Sphere08 from light LightA



Basically you choose an object (or objects), you choose a verb, then you choose another light or object, and possibly some tertiuary objects if working on shadow interaction.. The + and - icons delete or add a new rule.

The tool should include the following interactions:

- excluding/including an object from a light's illumination
- excluding/including an object from a light's shadow casting ability
- object to object shadow interaction (object Sphere07 doesn't cast a shadow on object Sphere08 from light LightA)
- excluding/including a selection set from a light. This would be an excellent way to exclude a whole set of objects from a light without having to constantly refresh your include / exclude lists every time you add a new object to a scene. Adding an object to a selectionset would automatically update the include / exclude lists.
- excluding/including a layer from a light. Similar to the selection set idea.
- lights brighten or dim on a specific object (Multiplier)

The big advantage this system has is it allows the user to directly translate the director's request to the software, and under the hood the software figures out how to wire the various include/exclude lists to achieve the provided rule. Also, since it's a single part of the interface for light rules, it's easy to access rather than hunting and pecking through a bunch of different lights in your scene to get at their individual lists.

Merging scenes would also merge these rules as well.

- Neil

[Crush]

I'm curious, isn't that kind of adjustment better solved in comp?

[soulburn3d]

I'm not sure I understand the question.

Lets say I have 2 characters and a light, I want the light to only hit one character, to do this in comp I'd need to render one character, then I'd need to turn off the light, render the second character, turn the light back on, then deal with 2 renders instead of 1. Or, I could have 1 rule in the render using the include/exclude system. I could still render the characters seperately in case I wanted to make color corrections at the comp stage, but at least I wouldn't have to worry about modifying the scene manually.

Do you have an example where the comp solution would be simpler?

- Neil

[Art48]

Depending on circumstances you could subtract a specific amount via the lightselect element.

[Crush]

Oh, I thought you guys render in multiple passes and assemble everything in comp anyway.

[soulburn3d]

I use vray for my personal projects, so there's no "you guys" And I do render out multiple passes, but like to keep as much as I can in the beauty pass to keep things simpler.

- Neil

[Crush]

I see, got thrown off by the director example.

[soulburn3d]

Ah, well, if I did work at a place that used vray, I'd like those same controls And in the case of my personal work, I am my own director, and I'd like those controls too

- Neil