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rawb
01-21-2011, 05:06 AM
Hello everyone,

I am relatively new to the 3d scene, maybe 4 months now. I am having some issues with lighting and consistancies and was hoping I could get some advice. My issue is primarily with lighting. I am fairly comfortable lighting an interior scene, and have found some extremely helpful tutorials and videos for that, but I am having a horrible time trying to do the lighting for an exterior scene.

Right now I am working on modeling a building for class and I find that when I render it the quality drops from the real-time model (the settings are set to production quality, and raytracing is enabled). Which is weird, as when I light an interior (using linear decay and point light usually), the objects look very nice.. but this building is not coming out as well.

There's a few issues I am having.. I am not really sure how to go about lighting an outdoor scene..which lights to use, how many, where to situate them.. I find it kind of difficult to grasp. I believe t hat this is to be a night time scene, but I don't want the image to be pitch black or anything.

Which leads me to another query.. lighting an object for display. Say with that same building, I want to have the model for my portfolio, but with no environmental lighting, is there set ups anyone can suggest? Or tutorials? I am definitely looking for some tutorials on my own, but I know that a lot of people have their own resources they may like to share.

It's really frustrating as I just can not seem to get the same quality out of my image as if I were just lighting a room with a bunch of objects or something.

IF anyone is at all curious as to the level of my 3d skill (not very high, as I am new) a few of my scenes are being dumped at amadarien.deviantart.com. Also, I can post the model I am working on tomorrow if it would help.

thanks in advance!

kanooshka
01-21-2011, 01:10 PM
Welcome to the world of 3d!

I'd start out by going through this website: http://www.itchy-animation.co.uk/light.htm to really understand how light works, the more you understand, the easier it is to replicate. I'd also recommend getting a copy of Jeremy Birn's book, Digital Lighting and Rendering. It goes through lots of concepts and how they get applied into 3d.

As far as the scene you're working on now, I'd recommend starting with a daylight render, it's a little easier to work with as far as complexity is concerned. Start out with a directional light for the sun and then add in some fill light from the sky.

In the future I might recommend just posting an issue or two with some images. It's much easier to answer questions just a couple at a time especially when there's a visual to assist.

rawb
01-21-2011, 06:18 PM
Thanks very much for the reply! I read the tutorial and found it very informative and helpful. I am still struggling a bit with HOW to set up lights for exterior scenes and for displaying a single object.. but I still appreciate the link given!

playmesumch00ns
01-21-2011, 08:57 PM
Why don't you post your renders along with a description of your light rig and/or screengrabs of it and we can probably jelp you get what you want.

rawb
01-24-2011, 01:56 PM
Hello,

Once I finish texturing it, I will post some screen grabs! Thanks!

--
Edit:

Added the image here. I am not really satisfied with it, it lacks cohesion and unity (in the texturing). I am a bit of a noob, but I don't really think it meets my expectations, BUT I did learn a lot by building it and hopefully I can use it to learn some more. If possible ANY texturing tips, design, ideas.. lighting.. any of it would be wonderfully appreciated. I am very hungry to improve.

Thanks!



http://img690.imageshack.us/img690/6233/rendertest01.jpg

Kev3D
01-25-2011, 01:07 AM
Hi Rob,

Your building looks pretty cool

First thing I noticed is that the doorway is faceted. I'd give it some kind of frame with more subdivisions. If you want to push this model further, look into adding more details like nails, pipes, different shaped panels etc.

Lighting:
First, the yellow light source has no apparent source, you might want to try including some models for the lights around the building and give them a quadratic falloff.

I'd give the sky some colour, a dark blue, maybe some clouds.

Look at as much reference as you can. For instance, check out the recent Cabin Lighting Challenge (http://forums.cgsociety.org/showthread.php?f=185&t=911006).

Hope that helps.

rawb
01-25-2011, 05:51 PM
Thanks a lot! I am going to look at the link you showed me, I am very excited to see what it as to show.

As for the sky.. I am still sort of trying to figure out what to do for those. Do I do a dome and apply an image? Do I just use a plane? If I do that.. and I am lighting an exterior scene.. then what lighting would be best?

I am trying pretty hard to figure it out.. maybe a directional light for the moon light? And have softer, point lights for the blue shadows? That's what I was playing with here.

I also agree 100% that the tunnel is distracting. I was planning to add a frame if I decide to take it any further (model/texture wise). Also, I approached t his different than I should have. I didn't have a whole lot of time to work on it so I didn't really gather a lot of reference or do much concept - which I usually prefer to do. Although.. one thing I find frustrating is trying to think of the correct words to search for things like this. I am thinking of keeping a note pad handy when I watch movies now so I can write down any interesting locations and possibly research them later.

Kev3D
01-26-2011, 05:46 AM
If this is just going to be a still, you can get away with a simple background image on a plane in the background. If you're going to make an animation, you may want to look into using a dome. The plane would be self-illuminated, doesn't need any lighting.

For the sky light you could create a dome of spotlights, or use some kind of skylight system. I think point lights should be avoided in most instances as they are difficult to control. Maybe I missed it, what software/renderer are you using?

To me this kinda looks like a Warhammer style building so that might be somewhere you could look. You could also check out computer games like Half-Life or Unreal.

rawb
01-26-2011, 01:19 PM
Hey Kev,

Thanks a lot for the response. I am using Maya 2011 right now. I know how to make a rough sky with say, a ramp shader and turning the ambient slider up, but I think I'd probably try to go with an image (I believe I'll see if there's any tuts on sky domes or what have you).

The other thing is very interesting to me. A dome of spot lights? I think I saw a glimpse of something like that in a gnomon video I watched a while back. Any suggestions for setting something like that up? Also, I read a bit about something called.. Final Gather? Still researching on that too. If you were to use a dome of spot lights would you turn fog on, or would you use an environment fog instead? Also, would you use a dome of spot lights with say, a directional light for the sun (or the moon or whatever)?

Thanks again

Edit:

I was researching final gather and came upon physical sun and sky.. which seemed kind of cool. So I looked into further and decided to test it out (my building doesn't really have a ground yet, and I haven't made any changes to it YET - I Plan to- I just wanted to test out lighting options. So, I am posting a test of it.. but can I get others opinions on Mental Ray and Sun and Sky? Is that used a lot professionally? Is it better to add additional lights to the scene? Should one ignore it entirely? Also, I notice - and this may just be the resolution - that the bump maps aren't showing up very well. Any suggestions?

Double thanks again!

http://img84.imageshack.us/img84/5968/rendertestsunandsky02.jpg

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