LightWave - realistic interior lighting

[The Axeman]

By some accident I find myself torn away from my comfort zone of making crazy spaceships and vehicles, and thrust into the business world making interior visualisation shots. They send me a detailed plan of a room or indoor area, details of the stuff they want built to populate it, and then I get a couple of days to make it look as real as I can.

I build all the cabinets, furniture, rooms, etc and then when it comes down to making it look believable its all in the lighting. The stuff I have done so far has no exterior lighting at all, not even windows, so I'm mainly building downlighters into the ceiling and a few small spotlights. I was smart enough to turn radiosity on and get more even lighting, but not smart enough to tweak it or to get the lights to look realistic. I've started going through radiosity tutorials and begun experimenting, but I'm still nowhere near happy.

In short, how to I make a believable spotlight or downlight? I make a simple model of the light (including lens), stick a point light in it and set off rendering with radiosity on. I still get a harsh shadow line around the walls at head height and no hotspot under the light. I tried switching to a spotlight and made it wide, then turned up the soft edge angle quite high as well. Made no odds, harsh shadows. I found the best results were with a spherical light (LW10.1) which give a nice spread of light, but no hotspot and it's larger than the physical model of the light, so I dont get a glowing light, I get a glowing ring around the light.

Check the pictures attached for reference. They show a couple of scenes, one each with point or spot, and then with spherical.

How the hell do I do this? How do you guys do it? Help?

Kenny

[Rigel]

Nice reference photos. I think you'll find it tricky to match the lighting in that room.

Drink much?



First of all, a tip about the spherical light. You mentioned that the light is larger than the model itself. Open the properties panel for the spherical light and at the very bottom you'll see two inputs; quality and size. The size defaults to 10 cm. Make that smaller and it will shrink the light so it fits inside your mesh. The quality input controls how will it renders the light scatter and has a major effect on the shadows. The lower the number, the more grain you get in your shadow. The higher the number, the smoother the shadow and softer the edges. Please note that higher settings mean longer render times.

I'm no expert on interior lighting, but Otacon has always posted the most realistic arch visuals on our site. When asked about lighting (as he frequently was) I seem to recall he said he used area lights a lot. I think the idea is to set the overall room lighting with an area light, then create the hot spots with spotlights. My own experiments have shown me that it's very difficult to get a realistic room lighting just using the "light bulbs" in the mesh and radiosity. It just doesn't work the way real light does. We have to cheat, we have to fake it.

Another big part of the realism is how your surfaces work with the light; reflections etc.

Another thing you might want to examine is the Photometric Light. It allows you to load in an .ies file (which contains the data for an actual light bulb) and it mimics that light bulb. I've used those for street lamps on a street scene and it's very effective. Finding an .ies for a street lamp was easy. I'm still trying to find an .ies for a 60 watt indoor bulb. Problem is, light bulbs don't seem to be called something simple like, 60 watt indoor bulb. But if you can find the proper .ies files, it will give you an even more realistic light scatter.

[BillS]

ies is a great way to go about it. Rigel has one thing about them sorta wrong though. Its not really the lamp that is what the ies file has data on. Its the light fixture itself. ies data shows light dispersion for a given fixture. For example. This is a basic pot light.

http://www.canlyte.com/our-brands/li...3aIncandescent

If you click on the ies icon if the first type listed you'll see the list based on the lamp that they use. ( Anything with A-19 is a bog standard incandescent. ) Clicking on the name link on the left will download the ies file for that fixture and lamp.

In case you're wondering... that site is a gold mine for anything ies.... That's why I have it bookmarked.

[The Axeman]

You'd never guess the company makes custom wine cellars, would you?

Rigel, I tried changing the size of the spherical light but it doesn't seem to change in the layout view and it had no apparent effect on the finished product. I might be doing something wrong, it wouldn't be the first time. On the first & second renders you see I have used large area lights behind the camera and through that far glass door to simulate light spill from the rooms beyond.

Guys, I never even knew the photometric light existed until just now. I wondered how I might emulate a genuine lights specs, as I have made everything else in the room to the exact measurements provided. I didn't want to stick lights all over the place and give the wrong impression to the client, who ends up getting a suntan from putting way too many lights in a room. I've changed the lights in the first scene to photometric 5" downlighters, but now I cant see a damn thing as its so dull. Are there specific settings I should have on to make it look correct?

[Andrew March]

Have you thought about using self illuminated objects that are invisible to the camera?

Would you like me to take a look for you Kenny, I'm not doing anything so really wouldn't mind mate.

[The Axeman]

I am already using glowing patches in the cabinets to fake LED lighting, and it works quite well. If I ever get one of these with an outside window I'll probably make a skydome and have it glow and self illuminate.

I replaced the IES file with one from a different type of light which works way better, so I'm rendering out a test now. I think photometric lights may be the way to go, I just need to get my surfaces fixed now. I have no info on what they're made of apart from one wall which is polished limestone tiles.

[Eden]

I would agree with the others on this if your looking for realism then IES lights are the way to go, although they may push your render times up quite considerably depending on what you are trying to achieve.

Here a nice little set of 30 IES Lights for you and any one else that wants to play with photometric lighting. The RAR has two files one with the date the other file has icons so you can see what the lighting looks like….

[The Axeman]

Cheers for the IES lights, I'll check them out tonight. I've attached a redo of the scene with photometric lights, and it does give a better feel to the thing. Before the lights were rather too intense on anything nearby, and now there's a more even feel to it. I dont think this scene really lends itself to good lighting, but it's worth a try. After doing some radiosity work and reading up on it, I managed to get the render time down by a third, even using photometric lights.

[3D_CG]

Cool Renders

[today]

Assuming that the final product is meant to be a still image (or set of still images), have you considered using post processing to achieve the desired result?

Depending of course on what look you're going for.

edit: A little contrast enhancement coupled with some levels adjustments and some color grading could really add some extra "pop" to that last render

edit2: if you don't mind me giving it a shot:



Obviously postwork is a matter of taste.. I prefer things a bit more contrast-y, but that's not the only way you could go with it.

[The Axeman]

Yeah, I just have to provide stills at this stage, so I usually run it through Photoshop to play with contrast, etc. With a couple of the first ones there was a chandelier as well, and I added small lens flares rather than try to do it in Lightwave. I also usually give it a gaussian blur of 0.2 or 0.3 pixels just to take any edges off. It's easier than doubling the render time with more passes.

Edit: just checked out your redo, interesting but probably not what the clientwould want. :-) I'm an old B&W photographer and I roo love contrasty, moody looking lighting in my stuff, but I have to restrain myself for this. They wanted even, bright lighting (but not too bright) to suit the Spa environment, not the Batman style Gotham look I might give it. I'm awaiting feedback on this room anyway, I didn't have a lot to go on as it was a rush job.

[today]

edit: ah, back-to-back edits.

edit2: How about turning off all the lights and ramping the radiosity to something crazy like 1000% with a dozen or so bounces. It's somewhat hit or miss, but if you're modeling in the light sources anyway it may work out ok. You just have to make sure to keep the surface luminosity pretty low, and keep ramping up the radiosity until it looks right.. VPR is pretty useful for this if you've got it.

[Omnipotent]

Originally Posted by today

edit: ah, back-to-back edits.

edit2: How about turning off all the lights and ramping the radiosity to something crazy like 1000% with a dozen or so bounces. It's somewhat hit or miss, but if you're modeling in the light sources anyway it may work out ok. You just have to make sure to keep the surface luminosity pretty low, and keep ramping up the radiosity until it looks right.. VPR is pretty useful for this if you've got it.

why are you doing it that way? radiosity can actually produce some real good resutls without having to turn the intensity up and still getting more then managable rendertimes given you know how to use it correctly.

[The Axeman]

I have used crazy amounts of intensity on luminous surfaces in order to get them to light an area when using radiosity, but I would never ramp the radiosity itself to those levels. After experimenting with tutorials and some test scenes I actually render radiosity most of the time with a 100% intensity but only 50% multiplier to speed things up greatly without really hurting the quality.