Learning lighting

Update 27/7: New scene! Read my post here

I thought i needed to get better at lighting (I’m working on a short with a friend,
and it turns out neither of us are really good at it).

I’m starting with the really basic stuff, but i think I’ll try lighting some scenes
that resemble what I’m actually going to do for the project afterwards.

The renders are all Blender internal, without AO (I restricted myself to lamps).
The first one (the one with the single glossy ball), was created following a
tutorial/making of of the movie “Pigeon: impossible”

Anyways, find five flaws, or more - or less if you feel like it :slight_smile:
I would appreciate comments and suggestions quite a lot!

Also - does anyone have some suggestions for tutorials or exercises in this area?

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I think this looks great for a BI render. I don’t know any tutorials on this sorry. But I’d love to see your light setup:eyebrowlift:

Thank you :slight_smile:

Here are the blend files. These files were designed to be gamma corrected,
so they will seem really dark before they get composited (so don’t disable compositing)
but i reckon a similar setup could be used without gamma correction, you would just
have to use lights with a higher intensity.

Attachments

01.blend (474 KB)02.blend (244 KB)03.blend (457 KB)

[quote=TobiasDN;1431286]The renders are all Blender internal, without AO (I restricted myself to lamps).quote]

It looks to me like you used radiosity. If not, can you give me any tips or pics of the setup?

BTW, nice renders!

the only criticism i have for you is that the lighting is really bland, no really light or dark parts, no interesting shadows really, a little dark on a few of them. try making the light have more of a “direction”

Probably coloured bounce lights.

Well, i posted my blends in the last post, so you can see my setup there :wink:
But yes, i use colored bounce lights. The gamma correction does add a bit too.

Brados33:
Yes, I think that is my main problem currently.
I’m not sure whether the current lighting is realistic or not, but
it is quite dull :-). Ill be moving to the more artistic side of things soon.

@YellowLambo
The ‘tutorial’ TobiasDN is refering to, can be found here.

I can see that you got a good understanding of this technique that consist of placing bounce lights and shadow lights.

The most important change I can see is that your lights are way too dim. In all of your scenes, I could increase the lighting by at least 3 times. The 3-balls scene I could increase the lighting by 8 times. This gives a much better dynamics to the scene and the uniformity of the lighting is less bothering. If it is truely dim lighting that you are looking for, then that is another story. You would then use a lower gamma correction and desaturate your render a bit.

Another observation is that you set your sun light color to blue. The sun should be yellow while the sky is blue. This adds a nice color contrast to the render.

Yet another observation is that you use colors on your walls and floor that have zeroes in some of their RGB channels. You need to avoid that as those make it impossible to color correct after the fact. Beside, real reflectance never completely absorb light for any spectral span.

Overall, though, you are using way too many lights to get the result you get. You could get as good results by using much less lights. 43 lights in your 3-balls scene is a lot. and a few of those lights are area lights. At this point, you would be better off using Yafaray. This technique of adding bounce lights will require a lot of tweaking time from you. This is where the difference between a more physically realistic texturing and rendering techniques starts to pay off. It might take longer to render but you, as a lighter / texturer, don’t have to spend hours, even days lighting your scenes. Expecially, if the end result you are looking for is realistic lighting and texturing. The other way IMO, is to not attempt photorealistic lighting but more artistic lighting and avoid having to use tens of bounce lights.

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Thanks a lot for your in-depth comments :slight_smile:
I was writing an in-depth answer too, but it ended up being longer than anybody could benefit from.

Some of your comments i immediately found to be useful, and i thank you a lot for them :-).
Especially about the sun color, and using too many lights.
Some of them, however, especially the one about tripling the lighting, made
me wonder if our screens are set up differently. I found your corrections to the 3-ball
to be way to bright, having washed out areas around the windows and so on,
and being unnaturally light. But i was going for dimmer lighting, and your suggestion
to lower gamma correction and desaturate worked quite well :wink:

Anyway, again - thank you very much for your comments!

Hmmm. “Washed out areas around the windows”? I also wonder if we have our monitor set the same way because there is no wash out on my monitor. The walls are very bright but that is because I try to use the whole dynamic range of the image. It is definitely not washed out here though.

You may want to visit this monitor calibration site est go through the test patterns to make sure your monitor is setup so you can use the whole dynamic range. This, notwithstanding the fact that you are looking for dimmed lighting.

Here’s another site that is pretty helpful :
http://www.lagom.nl/lcd-test/

Yup. Those testing patterns are very good too. I had lost the link to this page. Thanks for sharing it.

ypoissant…you could post your blend ?
Your image is very realistic…

thanks

Thank you for the links. Although there did seem to be room for improvement in my monitor calibration, it didn’t seem to change an awful lot about the image, so I’m back to thinking there is something wrong with me, rather than the screen :slight_smile:

I’m not sure “washed out” was the right way to put it :o
Well, the window sills and edges are completely white in ypoissants render ( at least on my screen) and in the top right corner of the last window, the light spreads to the wall, still being completely white. Do you see this too?
Besides that. there are small white dots between the ceiling and the back wall, though I’m not sure what causes them.

If you do see these, it really must be a taste issue (though, of course, your notes on making dimmer lighting did help - so it may just be that your rendition is aiming for a different kind of lighting). Otherwise i may have to get a new screen…

sorry if I’m starting to bother y’all with this :frowning:

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Hey Tobias. Your render doesent seem to be much different from ypoissant’s. I think it must be your monitor-settings.

Hi. There is some good info in here. I also watched that podcast on the single pass lighting. So your not just learning lighting but helping teach it as well.

Here is how I did the render: There are 43 lights in this scene so I did not go and multiplied each one of them by 8. That would have been very hard to do for several lights because Blender does not allow to increase the light energy beyond a certain point. And beyond that point, I would have needed to play with the distance and with the inverse square falloff (I did not verify that but I assume you are using the inverse square attenuation on your lights except for the sun), it complicates the issue quite a bit.

Anyway, modifying the lights seemed like a too big task. So what I did, instead, is that I kept all the lights (except for the sun) as is and I added a Curve node in the composite nodes and I multiplied the whoile render by 8 with the help of that Curve node before applying the Gamma correction. This is a perfectly valid way of achieving the goal.

As for the sun light, I increased its intensity quite a bit because it was really not strong enough in the initial setup. The initial render of that scene was not only very dim but showed a sun that was totally lacking energy. So I corrected that in addition to setting the sun color to yellow.

Yup. I see that too. But I have no problems with that. I’m pretty sure that if I were to take a photograph of a real room lit only with a sun and the sky with an aperture wide enough that I could see the room illumoinated the way it is in the render, then the window sills would be saturated with light too. If there is anything that would help concerning the windows sills, though, it is that their geometry could be complexified by adding whatever it takes to hold the glass in place. But I did not worry about that. I focused on the general lighting feeling.

and in the top right corner of the last window, the light spreads to the wall, still being completely white. Do you see this too?

The light is not spreading on the wall but rather, the shadow in the top portion of the window corner is pushing the averaging of light further outside. I may have pushed the sun light a little too high though.

Besides that. there are small white dots between the ceiling and the back wall, though I’m not sure what causes them.

Those are likely antialiasing issues caused by using the RGB Curve node instead of adjusting each light individually.

BTW, I did not save the modified blend file. I will revisit it and save it this time.

Well, I thought I did not save the blend file for my previous render of this scene but I found out I saved it so here it is.

I also played with this scene a bit more.

First I tested Blender radiosity. My conclusion is that this is unusable as it implemented except for some specific purposes, I guess, but I can’t imagine one of those purposes. Whatever, the parameters does not inspire confidences from mi part. In particular the Mult and Gamma parameters make absolutely no sense to me in the context of calculating a radiosity solution.

Then I decided to relight this scene with a minimal set of lights. The result is attached as well as the blend file. This uses only 3 lights plus ambient occlusion. It is not complete IMO, and could use some more tweaks but I already spent more than my alloted time budget for this (thanks to Blender radiosity).

Some more observation about the scene setup:

  1. The room was missing double walls. This produced strong light leaking on the walls from the outside lights.
  2. Materials are way too saturated. This makes it very difficult to produce color bleeding in the scene because they basiscally all cancell each other. For example, since the blue ball have nothing in its red and green component, it becomes impossible to bleed the red from the floor.
  3. There were some lights with inverse linear attenuation.
  4. The sky colors were very dark.
  5. The main area light placed outside was not large enough and could not cast all the proper shadows from a sky through all the windows.
  6. The atmospheric settings was casting an overall yellow tint on the whole scene which defeated efforts to get nice blue/yellow contrasts.
  7. All the lights were too dim. I increased all the light intensities but in the end, I did not use most of them.
  8. The sky through the windows reflecting on the yellow ball is too dim. This I did not fix. To fix that would require a geometry as a sky dome with a strong light shining onto.
  9. The yellow ball had its reflection color set to white. I changed that to yellow. White would be plausible too for a glazed ceramic but the reflectivity would need to be handled differently with a true Fresnel effect.
  10. There were a few other minor issues but I did not note them.

You asked for lighting tutorials. I don’t know of any really good lighting tutorial. One thing you could do if you want to know how far you may be from photorealism, is to setup and render the same scene in Yafaray or LuxRender. That way, you would get to see how light bounces and bleed and how shadows are distributed. Apart from that, you could participate in Jeremy Birn Lighting Challenges on CgTalk where you would get usefull comments and criticism.

Attachments

03b.blend (455 KB)03e.blend (448 KB)


Thanks to all of you for your advice!

Ypossiant:
Thanks a lot for your time, sorry you had to exceed your budget ;).
Number 3 “inverse light attenuation”. Does that mean the negative lights? (I’m not a native English speaker, should you not already have guessed it).

Just to be clear: I am not trying to get realistic lighting as in “it looks like it would in real life”, i am rather trying to learn how to do light that is believable.
I do, however, think that your new render is quite dull, and at least quite far from what i was trying to achieve. I seems to have a sort of overcast-day feel to it, rather than the sunny day feel of your earlier render. But this may of course simply be because you felt you spent enough time on me (which you certainly did), or because your end goal was different than mine. I think this is most clear when you talk about getting rid of the yellow tint, a tint i thought added a great feeling to the scene :stuck_out_tongue: