Two queries for Lights- Lights in Components & Emissive Materials

[Macho3001]

Hi

I have two simple queries.

1. I am modeling a large interior office scene (which I will post upon completion) that has a significant number of Rectangular Area Lights in the False Ceiling for totally enclosed space (No Sun). I am facing a tough job tweaking them one by one; Is there any way, settings for multiple similar lights could be altered by making them as components ? I tried making area rectangle (groups) as components, but then the light doesn't function as a light anymore. & I am not getting the result I want by using Emissive material as mentioned in my query 2 below=>

2. If I 'componentalize' geometry with emissive layer & duplicate it all over the scene I'm able to tweak all lights simultaneously, but then the results come flat & washed out as compared to using Area Rectangular lights which provide a great deal of depth to the scene. Should I be using extremely low multipliers (reeeaaly low?) for emissive materials for illuminating the scene? The Manual (& many other places of the forum) I've read emissive materials should not be used as rule of thumb for principle illumination in the scene..? Or is there a workaround ?

I request the experienced users to please comment, any help is highly appreciated. Thanks.

Macho

(Afterthought edit: Also, how are the rendertimes in comparison between Area Rectangles & Emissive materials as light sources..: I have about 40-odd lights in the scene)... Thanks again.

[Macho3001]

Re: Two queries for Lights- Lights in Components & Emissive Materials

3. Is there a way to apply decay (L/I/IS) to light emitted by Emissive material ? 'coz then I could give it enough depth comparable to Omnis.

How would one go about the best way (vis-a-vis short test render times & depth of illumination provided by Light) for making CIRCULAR Recessed Ceiling Lights; from the options below:-

a) Circular hole pushpulled back in ceiling with an intersecting Area Rectangle light so that only the circular portion of the light is visible from below (my preferred; provides depth to scenes but multiple lights need individual tweaking !!)

b) Circlar Geometry being assigned emissive material (permits multiple lights editing but gives flat result due to absence of decay)

[thomthom]

Re: Two queries for Lights- Lights in Components & Emissive Materials

Emissive materials aren't meant as primary lightsources.

In the original VfSU you couldn't use lights in components, but in SR1 it does. I did a test scene where I added a point light to a road light which lit up the entire road: http://asgvis.com/index.php?option=c...25301#msg25301


Unfortunately there isn't any way to adjust multiple lights. I have previously added this to the wishlist forum. http://asgvis.com/index.php?option=c...0&topic=4920.0

[dalomar_cg]

Re: Two queries for Lights- Lights in Components & Emissive Materials

Do your best to use emissive materials as sparingly as possible...the reason is because they are sampled as a material as opposed to being sampled as a light source. This is fine if you're not using them for the main lighting of your scene, but very problematic if you are. There's no direct light from emissive materials, its all considered as GI...so it would be very hard to get the speed and crispness (whether thats a sharp shadow or a blurry one) that you would from an actual light. This also means that your only adjustment of quality is your GI algorithms, and since there's no direct light, you'll have to pay significant attention to your secondary bounces.

Since emissive materials are treated as GI, there is always an inverse square decay. However, this is by the design of the GI algorithms...since there's no direct light being traced, there's no real decay applied.

Bottom line...use Rectangular lights whenever you can...also try to avoid using very large rectangular lights above a ceiling with a few holes...this causes bad sampling problems.

[thomthom]

Re: Two queries for Lights- Lights in Components & Emissive Materials

Bottom line...use Rectangular lights whenever you can...also try to avoid using very large rectangular lights above a ceiling with a few holes...this causes bad sampling problems.

Rectangular over point lights as well?

[dalomar_cg]

Re: Two queries for Lights- Lights in Components & Emissive Materials

Rec Lights vs Point lights is personal preference. As long as they are a light (not an emissive material), then the will get sampled in the best way. Some situations are better suited for one as opposed to the other...typically, if I have a grid of lights or something, I'll try to keep those as point lights because there will be less tracing involved... also, for interiors I like using point lights with inverse decay as opposed to inverse square (rec lights only have inverse square decay)