internal lighting

[ZFact]

Hi all;

I have been creating external stills for a few years now and can

honestly say im happy with what i am producing... every image i do

improves slightly on the one before it... i think its the fact that my

images are improving that gives me the drive to better...

 

unfortunatley, I cannot say the same thing for my internal still images.

My lighting always looks really flat and i struggle to get any sense of

depth into my scenes... especially scenes which have no windows

and no external lighting streaming in... ie... a bar or restaurant at night.

 

can anyone give me any advice on improving... perhaps a step by step

guide of how you guys light up your scenes... i think my biggest problem

is that i generally have to much of an even spread of light across the hole

scene... not enough dark areas to highlight the broght areas etc..

 

do you use omnis.. areas or spots... or a combination...

do you get your direct lights sorted out first and then place fill lights where you want more brightness... etc etc

do you enclose your scene to keep bouncing light in

 

any tips would be great

Thanks

[STRAT]

aye, interior lighting in the AR is an art in itself, but most satisfying when done correctly and in reasonably decent render times.

 

speed is your main concern - whatch out on blurry materials and high sampled area shadows. Also, i dont personally use area light for general lighting. slower than normal lights and not needed imo.

 

Also, do you want to use gi or not? because of render speeds i'll use both. And i'll use the gi as a general infil backround light, NOT the main lighting.

 

so generally, for a gi lit internal.......

 

1) set up the general external lighting, ie, a sky object with a luminance channel for the general sky emitting gi. and an infinite light (with shadows) as the sun.

 

2) start putting in lights in your scene where there are actual lights in the design. ie, wall spots, ceiling lamps, table lights etc etc. make these lights individual omnis with falloff or distance clipping. (i'd always use far distance clipping personally). again, dont use area lights.

 

3) if it's too dark (it'll more than likely be too dark than too light) add 1 or 2 omni lights in the middle of the room(s), at maybe 5 or 10% strength, turned to ambient mode, with soft shadows. These are your fill in lights.

 

4) a ball park figure for your gi settings might be -

 

strength - 100

accuracy - 70

prepass - 1, 2 or 3

diffdepth - 1 (no more than 1)

stochsamps - 700+ (whatever the highest you can afford)

min - 50

max - 250 (or higher if you can afford)

 

thats about it. Change the lighting levels by changing the ambient omni levels, and NOT the relevant gi settings. Same applies for a non gi settup - the above instructions will work but you'll probably need more or higher infill omni ambients.

 

Also, gi or not, run an AO pass over it to help enhance the shadow contrasts. and dont forget your levels/curves/contrast settings in photoshop at the end either.

 

here are a couple of past examples i've done to show you the results of rendering internals on the AR with and without gi, using the above instructions as a guide -

 

WITH BACK ROUND GI ON -

 

 

 

 

WITHOUT ANY GI -

 

 

[Billabong]

Strat, your work is beautifull, and thanks for all the tips, I do have one question, what is back round GI, are you just talking about regualr GI?

[STRAT]

thank you.

 

yup, backround gi is just regular gi. i just use gi with regular (not high) settings to give my imagery that 'real' gi feel. i rely on local lighting to be the star of the show. thats usually ambients or attenuated omnis. i hardly (if ever) use area lights to illuminate my scenes.

Thants why i call it backround gi.

[Billabong]

I don't mean to steal this thread, if i am, just tell me and ill start another one, i just thought since it was relevant, just to ask in here, can you explain a little more on your ambients, Im pretty sure with omnis, you use falloff, with soft shadows, but im not to familiar with the ambient term

[STRAT]

i wouldn't personally use falloff, i find it a bit harsh. i use far distance. it's a lot softer and more subtle.

 

ambients - select your omni light, then in the light's 'general' tab, tick off diffuse and specular and tick on ambient. (you might need to turn the intensitys down a bit too).

[ZFact]

thanks for the advice Stephen

I'll play around with it and see how i get on.

 

Do you know anything about lighting setups using

FR2.. do you generally use the sanme technique?

 

Do you evr use IES lighting?

 

Thanks again

[STRAT]

dunno much about FR2. i have it sitting on my shelf. i played around with it initially, but it wasn't stable enough for me to rely on. but in vray i use a similar technique, only i use gi more than ambient omnis.

 

jup, i'll use ies lighting where it warrents it.

[jo3]

im coming into this conversation a bit late, but i have a question about gi as well. i have noticed different colors in the prepass, green, white, red, pink. i havent been able to find a description of what each one means. im assuming white is a sample looking for a light source and has found it, red is one that has not, but green and pink im not sure. any ideas?

 

thanks

 

jo3

[gdrakakis]

Also, do you want to use gi or not? because of render speeds i'll use both. And i'll use the gi as a general infil backround light, NOT the main lighting.

 

hi STRAT,

does this mean that you exclude the main lighting from the gi calculation with comp tags?

it sounds interesting as a method, but aren't you missing the advantages of gi? (-> spreading the main lights illumination according to the diffuse depth?)

i guess the answer is no if the diffuse depth is set to 1, as you often suggest, but i would really like to know.

 

dunno much about FR2. i have it sitting on my shelf.

any chance to sell it?