advice for lighting

[Tim Saunders]

I have been asked to do a night-time rendering with the exterior lights that will be used in construction. They want as accurate of a display that the actual lights will be as possible. That is why I have used the apropriate ies lights. My problem is I am not sure how to set up my "atmosphere lights" like the moon, other reflective lights from the city. So far I am using a daylight system, but it is set up for night time, so i'ts not really doing anything. To symbolise other lights I have used an ies sky. When I render with my current set up, I don't really see the lights on the building much. I have included my current settings. Any suggestions would be great. I am using stock viz 2005 and radiosity.

[Tim Saunders]

one more image so you know which lights i'm concerned about. i do plan to have the interior lit and some other exterior lights, but i just started with these and wanted to get this problem worked out before i get all the lights in hte scene. thanks for any help.

[William Alexander]

It's all there, just way under exposed. Might want to try the exposure controls. This rendering may benefit from the linear control or uncheck the daylight exposure in the log controls.

 

You can use PS and adjust the levels also

 

 

WDA

[Tim Saunders]

yeah i can do all the post editing in ps, but most of the scene is brightened and that's not what i'm looking for. it's not realistic to what the lights are actually doing. i'm not so much just trying to make the picture look good this time, but it's almost an experiment to show EXACTLY what the ies lights will do. my question is, what other lights would be the most accurate in simulating moonlight, and other reflective lighting from the city? you know real world settings. maybe there is no way to do this.

[raysyu]

night lighting is more conplicated than day light. I have one critical experience, that is: you have to take care of the ceiling right after setting up the ambient light, because ceiling is the brightest spot in the night view and it is the only place that is directly lit. so if you using scanline renderer, the spotlight should shoot to the ceiling insteat of the floor. if you use mental ray or vray, the light could shoot the floor and it bounces back to ceiling.

[Tim Saunders]

usualy i just use screen mapping in my environment. are you suggesting that i set up a dome for a ceiling and any atmospheric light will come from a light reflecting from the dome? just not sure what you mean by ceiling.

[raysyu]

ok, seems like my answer is out of you question. if you wanna moon ambience, better use HDRI map, which echoes the moon environment. pick the hdri upon both sky light and environmental map. use spherical environmental sample in coordinates section of material editor.

[enigma]

as for me, with regards to night environments, i seldom use GI, i just fill in a mix attenuated lights and some omnis to stand for the environment ambience as it would render faster i guess.

 

post the scene lets try it out....

[raysyu]

yes, i totally agree, i used that way pretty often. But in mental ray, for exterior view, i don't use GI, which takes forever. Only FG is good enough if you arenot picky about details. Further more, the speed is not slow at all for test rendering, however, the result is just stunning. It is hard for me to turn my sight away from HDRI right now, it is so cool.

[Tim Saunders]

not sure what hdri is.

i sure apreciate the direction and willingness to help. i'll post the scene if it helps. if you have any problem accessing the ies files, i'll post them seperately. of coarse you will be missing some materials, but i'm not too concerned about that because i'm not even done with that stuff.

[Brian Cassil]

Hi Tim,

 

When I've done night renderings, I usually turn everything off and set the environment up. Then, I'll go and add all the bling bling and sparkle. The suggestions here are good ones. I know your client wants to see what it will "really" look like, and thats fine for the artificial lighting, but for the environment, that could be anything: Full moon cloudy, full moon clear, no moon, partial, dusk, etc. You need to just get the look you want, then go and add all the extra lighting.

[Tim Saunders]

good point brian. i was just talking to a fellow who sits near me and she said the same thing. any night can look different from another. i was kind of aproaching it backwards. i first set up the artificial lights because they were a new type of light for me, so i wanted to get them all figured out. then i put in the natural lighting. maybe i'll turn them off for now and see what i can come up with.

[William Alexander]

yeah i can do all the post editing in ps, but most of the scene is brightened and that's not what i'm looking for. it's not realistic to what the lights are actually doing. i'm not so much just trying to make the picture look good this time, but it's almost an experiment to show EXACTLY what the ies lights will do. my question is, what other lights would be the most accurate in simulating moonlight, and other reflective lighting from the city? you know real world settings. maybe there is no way to do this.

 

 

Moon light / sun light works exaclty the same. Moonlight is 10,000x less than sunlight in intensity and a different temperature of light. So with moonlight you have 1 fc illumination from the moonlight and a fraction of that if the stars are out for the skydome, partly cloudy maybe a bit more reflected light from the city lights. At low light levels the realistic 'mechanics' of physical lighting are not the controlling factors of how real it looks, it's perception. The human eye, Film or digital response's to the light. Perfect lighting will only get you so far, the rest is understanding the media of perception you are trying to emulate. Nightime lighting is more of an art than a science. I'd collect some reference pictures of night shots and work your lighting from those.

 

I'd start with an ies sun (moon), skydome (sky influence) and direct or area light light, for the 'city lights'. Then comp a sky image or rendering of a sky into the scene in post. You need to keep contrast and saturation lower than a daylight scene. If you have lighting on the buildings those need to be the inverse.

 

My 2 cents. Keep posting your results, this can be a very interesting topic

 

WDA

[Tim Saunders]

i tried a few suggestions that have been giving with not much success. the image below has the natural light that i am looking for. i don't want it lit much more at all. i doo however want to see some hot spots at least from the artificial lights in the scene. the viz help says to not change the candelas of ies lights because they are designed to show the same luminence of the real thing. but i am not seeing the effect of all these lights in my scene at all. the only thing lighting it is the natural lighting wich is an ies sky with an multiplier of 0.5, and an ies sun with an intensity of 2. the second image shows all the lights i have in the scene that should be "shining." the only thing that really changed is the rendering time. it took 15 minutes to render this at 800x600. like 3x as long as it dd without the artificial lighting, but no new effect.

[Tim Saunders]

okay. here's an update. i think i have just about the effect i am looking for. the architect want to see the building in the middle of the night. i ended up trying out running the render through eith vray free. i took out my "natural light" and just left the lighting up to the artificial lights and gi. i do want to get rid of the little glows where the actual lights are radiating onto the upper facia. maybe i'll just exlude those areas from the lights? i haven't tried that yet. i assume the gi effect will still hit those areas even if i exclude the lights from them right? any other suggestions would be appreciated.

[Tim Saunders]

and yes, i'll be fixing the pavement and parking stalls.

[Brian Cassil]

Gettin there Tim. The thing that stands way out to me is the scale of the parking lights. They look way too squatty.

[Tim Saunders]

okay.

other than any vegitation that needs to be in the scene and some foreground on the second image, i think this is about done. plus i won't be rendering these so tall, i just used 800x600 for these test renders. thanks all for your input.

 

brian,

i agree about the light posts, but the specs have them, at the height they are modeled. so, i think i'll leave them since i'm trying to please some pretty picky "lighting-realistic" people this time around.

[John Dollus]

I know I'm late to this paty but...

 

The IES file you are using comes in at 600 lumens which is less than 20% the amount out of a standard office flourescent ceiling fixture so it won't be very bright at all or give a very pronounced effect across the surface.

With IES lights, the data is taken from a certain mounting angle as well so you will have to look at the actual fixture to determine if the ies data is coming in with the proper orientation. Additionally, the ies data is coming in as a rather generic white color. Outdoor lighting is usually a bit different than that but you will have to check the lamp type. Using the actual color temp will probably give you the best results.