View Full Version : Help with lighting a room


eclipze
08 August 2008, 06:12 AM
I'm currently in need of advise for lightning up this indoor scene. I'm not finished with texturing yet, but I wanted to get the lighting done first before proceeding further. I am using Maya 8.5.

Currently, I only have 1 light in the scene (spotlight). The test render is as follows: (from left to right)
a. Test Render
b. The entire scene (screenshot)
c. With ray-trace shadows (on the spotlight)
http://img381.imageshack.us/img381/9718/test1vb8.th.jpg (http://img381.imageshack.us/my.php?image=test1vb8.jpg)http://img240.imageshack.us/img240/2794/screen1ze6.th.jpg (http://img240.imageshack.us/my.php?image=screen1ze6.jpg)http://img242.imageshack.us/img242/1/test2rn4.th.jpg (http://img242.imageshack.us/my.php?image=test2rn4.jpg)

The settings I used for my spotlight/mental ray:
http://img240.imageshack.us/img240/7177/screen2yp1.th.jpg (http://img240.imageshack.us/my.php?image=screen2yp1.jpg)

I've read through several tutorials, but still can't understand how I can create proper lightings so as to render out something close to this render:
http://img157.imageshack.us/img157/4840/wip8ea3.th.jpg

The main questions that I have is:
1. How could I adjust the spotlight to give the "blur light" effect like this (taken from The Science of CG topic):
http://img299.imageshack.us/img299/7477/lightdistributionel2.jpg

2. I found a nice lighting tutorial (Illumination Tutorial)from this website: http://www.cgarchitect.com/resource...nce/default.asp, but its done in 3DS max, which is not the software that I'm using. Is there a similar tutorial done in Maya?

3. As seen above, I have problems when I turn ray trace shadows on for my spotlight - the entire scene goes too dark, hence I am unable to see almost everything. What did I do wrong here?

Any other advise regarding the lighting/render settings for the scene is also welcomed.

eclipze
08 August 2008, 11:58 PM
I stumbled upon the fantastic interior lighting tutorial from floze
(http://forums.cgsociety.org/showthread.php?threadid=657518&utm_medium=plugblock&utm_source=cgtalk)
using physical sun and sky (PSAS), and it turned out pretty good (although I had to change the ceiling in order to get sufficient light in).

a. render
b. changes
http://img122.imageshack.us/img122/1277/changesrh8.th.jpg (http://img122.imageshack.us/my.php?image=changesrh8.jpg)http://img388.imageshack.us/img388/8269/tvanimation00lf9.th.jpg (http://img388.imageshack.us/my.php?image=tvanimation00lf9.jpg)

Any tips or advise for improving the lighting?
(http://forums.cgsociety.org/showthread.php?threadid=657518&utm_medium=plugblock&utm_source=cgtalk)

BulletProof
08 August 2008, 08:30 AM
The render might be realistic regarding to the skylight system within maya. But sometimes that's not the right approach, especially when doing interieur renders. Try working with differents lights...portal lights f.ex

I'd also suggest that you work on your shaders, and adding details to your models...f.ex. small beveled edges, that will reflect the light more realistic. Adding a picture to the TV-Set..things like that.

SvenKalkschmidt
08 August 2008, 03:53 PM
you may want tot take a look at:

http://www.treddi.com/forum/index.php?showtopic=8436

and

http://forums.cgsociety.org/showthread.php?f=87&t=190232 (http://www.treddi.com/forum/index.php?showtopic=8436)

eclipze
08 August 2008, 07:33 PM
@BulletProof:
Thanks for the advise. This is the fully textured version of the scene:
http://img166.imageshack.us/img166/3843/renderedscenekm6.th.jpg (http://img166.imageshack.us/my.php?image=renderedscenekm6.jpg)

Every texture you see is accompanied by a bump map. I've also re-modeled some of the objects, especially the chair. I've added bevel to the PC monitor, TV and the notice board.

No changes in light settings, mainly due to the lack of time. I'll play around with the lighting settings once the presentation for the project is over.

@retro002
Thanks a lot! That's just what I was looking for.

Any comments on the textures and such?

SvenKalkschmidt
08 August 2008, 08:24 PM
Turn the bump factor down a LOT. It will look better, when it is way more subtle. Also your scene is very saturated with color, maybe you should lower that aswell. Take your time to read the threads I posted and do the tutorial with the scene on treddi.com. Then revisit your scene with what you learnt.

eclipze
08 August 2008, 07:42 AM
http://img525.imageshack.us/img525/7939/renderedscenev2yp6.th.jpg (http://img525.imageshack.us/my.php?image=renderedscenev2yp6.jpg)

I lowered the saturation for the textures, and decreased all of the bumps to around 0.28. The wall still looks a little too bumpy though. Should I remove the bump instead? And should I just go for a plain 1-color wall texture? (I see that in a lot of the interior render)

I'll be trying out the lighting tutorial at treddi.com soon.

BulletProof
08 August 2008, 08:33 AM
you'll just receive a realistic image, by using realistic textures. Try googeling some more or less hiress pictures of walls, floor, pick a picture from a tv-channel for your tv aso.

SvenKalkschmidt
08 August 2008, 08:55 AM
I guess much of the saturation problem is also caused by the light. You are overexposing your surfaces like the tv table, but below the desk it is too dark. The treddi.com stuff will help you further understand. The bump is still far too intense.

eclipze
08 August 2008, 04:59 PM
I've finally completed the tutorial from treddi.com, although I still need help with it.
This is the rendered image:
http://img295.imageshack.us/img295/5475/tvanimation4qw6.th.jpg (http://img295.imageshack.us/my.php?image=tvanimation4qw6.jpg)

The shadowed parts can hardly be seen, and the only way I can light up those areas was to increase photon intensity (for the spot light) to 1,000,000-1,500,000 and above, which resulted in weird shadows around the TV like these:
http://img401.imageshack.us/img401/5931/tvanimation1ds9.th.jpg (http://img401.imageshack.us/my.php?image=tvanimation1ds9.jpg)

My set-up is as follows:
Light placements:
http://img329.imageshack.us/img329/9871/ss3dh1.th.jpg (http://img329.imageshack.us/my.php?image=ss3dh1.jpg)

Lights:
http://img132.imageshack.us/img132/9823/ss1co2.th.jpg (http://img132.imageshack.us/my.php?image=ss1co2.jpg)http://img102.imageshack.us/img102/5404/ss2cy8.th.jpg (http://img102.imageshack.us/my.php?image=ss2cy8.jpg)

Mental Ray:
http://img337.imageshack.us/img337/7537/ss4uy0.th.jpg (http://img337.imageshack.us/my.php?image=ss4uy0.jpg)http://img329.imageshack.us/img329/1779/ss5rl0.th.jpg (http://img329.imageshack.us/my.php?image=ss5rl0.jpg)http://img102.imageshack.us/img102/3972/ss6rv1.th.jpg (http://img102.imageshack.us/my.php?image=ss6rv1.jpg)

eclipze
08 August 2008, 04:23 AM
Did some more test renders, but still no lead on how to solve the lighting problems of the shadowed areas.

Changes:
1) changed Final Gather's min/max radius to 2/15 from 0/0.
2) increased photon intensity of spotlight from 500,000 to 1,200,000 and 1,600,000.
3) increased Global Illumination photons from 10,000 to 80,000.

Render 1: Photon intensity 1,200,000, GI photons still at 10,000, FG radius still 0/0.
http://img329.imageshack.us/img329/3355/tvanimation5ti2.th.jpg (http://img329.imageshack.us/my.php?image=tvanimation5ti2.jpg)

Render 2: Photon Intensity 1,600,000, GI photons 80,000, FG radius 2/15.
http://img329.imageshack.us/img329/1187/tvanimation6qu7.th.jpg (http://img329.imageshack.us/my.php?image=tvanimation6qu7.jpg)

Render 3: Photon Intensity 1,600,000, GI photons 80,000, FG radius 2/15.
http://img50.imageshack.us/img50/4823/tvanimation7th8.th.jpg (http://img50.imageshack.us/my.php?image=tvanimation7th8.jpg)

I'm about to adjust the Max Photon Depth to see if it helps. Still need advise for improving this scene.

jeremybirn
08 August 2008, 04:58 AM
Work a little more on your lighting before you turn on GI or FG. Now that you have a sunbeam coming into the room, the next thing you'll want is the fill light from the sky. It should be cooler colored, dimmer, and much softer than the sunbeam.

Make sure you have test-rendered your scene and love the sky fill before you use GI. When you use GI (if that's how you do your bounce light), you'll probably need a much higher photon intensity or much higher GI scale, just to make sure you can see it. Adjust that after you get more lighting done, but before you turn on FG.

You could turn down the bump mapping on the wall texture. Some reflectivity on the floor and TV screen would help too.

For MR anti-aliasing, using a min and max that differ by more than 2 isn't really useful. Try min -2 max 0 for quick test renders, and min 0 max 2 for final output.

-jeremy

SvenKalkschmidt
08 August 2008, 11:18 AM
The shadowed parts can hardly be seen, and the only way I can light up those areas was to increase photon intensity (for the spot light) to 1,000,000-1,500,000 and above, which resulted in weird shadows around the TV like these:

If I am not mistaken, the weird shadows are caused by your area light samples being too low. I am not very experienced in 3d, also I use XSI, so maybe I am wrong here, but you may want to try cranking the area light samples up to 30-40 if you want to resolve your shadow issues. Your second picture from yesterday (with the weird shadows) is actually the direction you want to go with your GI solution, the others are far too dark. There is very little light in the shadows. Also you may want to work the composition a bit, I think it can be improved.

As Jeremy says, keep your AA values low for the test renders, you can dial them up for the final render.

Keep us updated and good work so far!

SvenKalkschmidt
08 August 2008, 11:22 AM
One more thing about the textures. Your desk will stay pitch black, no matter how much light hits it, if you have dialed the diffuse completely down. Do not set the diffuse color to pure black, but instead a very dark grey. Look at black items around you, you will notice, when they are in the light, that they're actually look rather grey on the lit side. But be aware there are exceptions to that "rule".

eclipze
08 August 2008, 02:29 PM
I found out that FG was the cause for my shadowed region being so dark.
http://img56.imageshack.us/img56/4710/fgcomparisonxy3.th.jpg (http://img56.imageshack.us/my.php?image=fgcomparisonxy3.jpg)

After turning it off, and tuning my Photon Intensity to 5,000,000...
http://img410.imageshack.us/img410/5396/tvanimation10wb2.th.jpg (http://img410.imageshack.us/my.php?image=tvanimation10wb2.jpg)

I am generally happy with the lighting, although there are definitely things that I could fine-tune to improve. The current intensity for the spotlight is around 1.9, which I will lower to reduce the brightness that the lighted area seems to have, particularly around the TV.

The computer/TV screens were assigned with a glass shader that I had created by following this tutorial (http://www.spafi.org/index.php?option=com_content&task=view&id=468&Itemid=29), but it doesn't seem to work in my scene. This is why I plan to try out Mental Ray material nodes, by using this tutorial (http://translate.google.com.sg/translate?hl=en&sl=it&u=http://www.treddi.com/forum/index.php%3Fshowtopic%3D1899&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.treddi.com/forum/index.php%253Fshowtopic%253D1899%26hl%3Den%26sa%3DG). If I can't get it right, though, I'll have to stick with what I've managed to do with so far due to time constraint.

Once again, thanks for the advise retro002 and Jeremy. Of course, more c&c + advise is welcomed. :)

SvenKalkschmidt
08 August 2008, 03:52 PM
You can use the mia shader in Maya to create a sufficent glass material. Just turn the diffuse to 0 and reflection/refraction to 1. You can get further info about it here:

http://xsi.wiki.avid.com/images/7/77/Architectural-library.pdf

Also keep in mind, that how good your glass looks will always be determined by what it reflects.

eclipze
08 August 2008, 04:29 PM
Well, I tweaked the diffuse levels on the shaders a bit, and managed to get this result:
http://img520.imageshack.us/img520/6144/renderedimageux7.th.jpg (http://img520.imageshack.us/my.php?image=renderedimageux7.jpg)

I think that's it for now, as I have to pass the work down to the other members of the group. I'm fairly satisfied with the result, although I do admit that it is far from perfection.

Thanks to all who helped out with various advises and critiques.:)

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08 August 2008, 04:29 PM
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