Lighting for bright sun/shadows suggestions?

Started by yesmine, March 27, 2014, 01:25:06 PM

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yesmine

Being a bit new to Terragen, I'd appreciate some suggestions on how to get good bright sunlight and shadows. So far, my scene seems to be coming out a bit flat, without the pop I'd like to get from bright sunlight and shadows (i.e the kind of thing that might be fixed by adjusting levels or increasing vibrance, etc.) It's basically sandy desert and bushes, but if I put the sunlight intensity at 5 then contrast seems dull though the colors are okay, and if I move up to 10 then it seems overexposed and colors/shadows wash out. I've read about GI settings, maybe turning that off, but I don't know enough to be sure what that would or wouldn't do.

Below are some examples, images that show great 'pop' in the brights/shadows, so if anyone has pointers or knows of a lighting clip I can study, I'd very much appreciate suggestions:
Thanks.

Stone desert with nice conrast: http://www.planetside.co.uk/forums/index.php/topic,18045.0.html
Disc-shaped rocks with similar sand: http://www.planetside.co.uk/forums/index.php/topic,4580.msg48706.html#msg48706

An actual photo: http://www.hanselmannphotography.com/AllBigPages/7874,%20Poppies%20and%20Yuca.html



bobbystahr

If you post the .tgd here we can all take a stab at your scene and maybe the reposted .tgd's will be enough of a tutorial
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

gregtee

You can also just do a gamma adjustment in Photoshop or some other image processing software, which is what I do.

Supervisor, Computer Graphics
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Dune

Or experiment with the gamma in TG beforehand and exposure in camera.

bobbystahr

#4
2 good tips but as I said unless were we to see either an image or a .tgd there's no way we can really accurately get a sense of what your problem is.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Oshyan

Agree with bobby. In my opinion the default lighting is setup fairly well for "bright", if you simply increase exposure a bit, or create surfaces with light colors. Unless you add heavy clouds, turn up atmospheric density, or have the sun near the horizon, you shouldn't be having big problems with this. But I do see people coming up with fairly dull, washed out scenes more often than I'd like and I sometimes wonder why it's happening. It really must come down to settings that people are changing, and I'm sure it makes sense to them why they're doing it at the time, but the end result is often - in my opinion - not ideal. So for me the first question is always: do you have this problem in the default scene, with default lighting and atmosphere? If yes, then either we have a different definition of "bright", or maybe there's something different with our monitor calibrations or something... In the end the main problem is there are so many variables and factors, not least of which is the sheer subjectivity of "bright lighting". So yes, bobby has a good thought: post examples of the stuff you're having a problem with. :)

- Oshyan

gregtee

I've found on average that I need to pull the gamma down as much as 20% on every Terragen render I do, and that's starting with the default scene.  Perhaps it's just my own aesthetic but to my eye at least Terragen's default setup doesn't provide deep enough blacks.  I do feel that the sun to shadow ratios are good so it's not a problem with the lighting, it's all in the post processing that TG does after the render is complete. 

TG does a nice job of rolling off the high end to avoid clipping, but if you save out an .exr you'll have to handle that yourself after the fact.  Everything I render I output as .exr with the intention that I'm going to do additional color and gamma corrections in Nuke, but then again I'm used to working that way since it's highly unlikely I'm going to get exactly what I want straight out of the render.  I treat renders like plate photography to be further manipulated in some image processing software package.  Then you'll have complete control.

Supervisor, Computer Graphics
D I G I T A L  D O M A I N

yesmine

Thanks for all the suggestions, I'm still experimenting with it and I checked one render in Photoshop, which does suggest that gamma adjustment probably would have the most direct effect in TG.  Gregtee's mention of deep enough blacks is on the money with what I've been noticing. I have a version of the scene done in Maya, after countless hours recreating a realistic terrain, that I'm trying to match up with the Terragen scene, and getting the same deep blacks in the Maya image has been tricky. But I admit it may be the limits of my knowledge of TG that are more an issue than TG's capabilities. I'm actually feeling very positive about what I've been getting today.

I'll post the .tgd if I give up, I just hate asking for more help from those of you who've helped more than enough already. I tell myself that all the things we learn while we're looking for an answer to something else is where true expertise comes from. At least it eases the pain :)
Thanks..

TheBadger

I agree with Greg about the blacks. Or at least I find it difficult to get the kind of blacks he is talking about. Anyway, I sure don't get them from default settings.
It has been eaten.

archonforest

I was also wondering about the same yesmine some time ago how come some guys are posting fantastic looking scenes(like blacks are really black and contrast is just awesome...etc) as my renders were pretty washed out/dull. Then I asked one of them and it turned out that there are some post process happening on these images(probably not on all). Then I called my old friend PS and suddenly my renders turned out more pleasing for my eyes. Generally I do not like post process...like when I take photos I keep the original one without alter it in PS as that is not my picture anymore. If my photo looks good it should look good coz I am a good photographer and not coz I am good in PS. Anycow...
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Dune

So how about tuning down gamma in TG in the first place?

bobbystahr

I myself rarely post process as I feel the challenge is to do it in the program designed to do it (whatever I'm working on in whatever app), but in TG2-3 I do 'adjust' things and do many test renders, for example the exposure slider that is in Camera settings and also conveniently on the 3D preview window left side  slider, click the +/- to expand the slider, and I often adjust the contrast in the Render Tab>Effects...haven't felt the need to adjust the gamma yet. Also lately I have been enjoying the effect of the Ambient Occlusion setting in the GI tab...adds real drama some times and helps a lot with the black shadow thing.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

gregtee

The whole purpose of post processing is to speed up your workflow and allow yourself access to tools that aren't present or ideal in the app you're exporting the image from.  Terragen's tools are very crude from a post processing standpoint compared to something like Photoshop or Nuke, but then again Terragen wasn't designed to be an image processing package either so I wouldn't expect it to offer a lot in that regard.  Putting too much of that stuff in there to begin with would likely be a waste of time too since there's so many other apps out there that do it better because that's what they're designed to do. 

While it may be a fun exercise to see how far you take an image in Terragen "right out of the render" that's perfect in every way, you're probably better off rendering an image that's on the flatter side yet retains a lot of luminance and gamma info that you can later slide around post process to achieve whatever look you're after.  That's why I always work in the .exr format because I can pretty much do anything I want with it after the render.  Add in the render layers and you have pretty much complete control over the entire thing, which is a huge time saver when you're under a deadline or need to match TG renders with other packages. 



Supervisor, Computer Graphics
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archonforest

#13
Thx for expressing your view on this. I agree with you 100% :D
(I like to see the viewpoint of a Pro since usually I can learn something out of it. Thx.)
Dell T5500 with Dual Hexa Xeon CPU 3Ghz, 32Gb ram, GTX 1080
Amiga 1200 8Mb ram, 8Gb ssd

bobbystahr

Aha gregtee...Add in the Render Layers being the key phrase here. Could I but afford the full deal I'd be gung ho on the multi pass, as t'was one of the main things I requested when features were being requested IIRC,...but my pension doesn't allow for that kind of cash out lay sadly. So till I can afford the big app I think I'll just aim a wee bit lower and try and do it all in TG2 but I do get where you're coming from. Back in the Imagine3D days we had a method where we could do multi pass renders using 'States', an Imagine3D feature where all the 'passes' could be embedded in all the objects texture info and it was a simply matter of turning off all the states except for say the beauty , specular , fill light, etc. pass. It is a superior work flow and some day I'll have it available. It was the one thing that almost had me buying Vue but TG2-3's over all quality and amazingly helpful user base for learning kept me here...and all the cool folks as well..
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist