Shadow Lightness help please

Started by buzzzzz, January 21, 2007, 09:28:54 am

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buzzzzz

January 21, 2007, 09:28:54 am Last Edit: January 21, 2007, 09:42:23 am by buzzzzz
Hi Gang!

I'm having a issue with dark shadows on the terrain. I would like to lighten the shadows just enough to be able to see terrain details. I have tried to do this with Global Lighting however when I get the shadow lightness the way I want it's to much light on the non shadow areas. I searched the database and found only one reference to this issue.

Quote from: JavaJones on December 31, 2006, 02:15:47 pm
That's probably a Global Illumination issue. Try turning off GI and see if it fixes it. If so see if it has a significant (negative) impact on your scene quality. If so you might try using a fill light setup instead (to simulate "shadow lightness" - scattered light). I can provide a fill light setup in a .tgc if needed.

- Oshyan


I would really appreciate any tips and even the fill light setup in a .tgc that Oshyan referred to in this Quote from another Thread.

Thanks!
Jay

Cyber-Angel

You know I have to agree with you on this point, there is no control right now are there was in 0.9.43 to control the shadow lightness but as with all these things the stock answer around here seems to be "It will/ should be in the final release" this is all vary well and I understand that only a limited amount of the feature set that will be present in the final version could be in the tech preview, but still it dose seem a little like the adage that is prevalent in the Motion Picture industry "We'll fix it in post" Umm, news flash some times you can't just fix it in post.

Talking of GI I have noticed that there seems to be features missing form the GI, things like:

•   Colour bleeding between surfaces

•   Sample Resolution

•   Intensity Falloff.

True Soft shadows (In real life shadows become softer proportionally to the distance form the object making the shadow, you can test this your self put on a light and put your hand next to a white wall at a close distance and you will see that the shadow of you hand is a hard shadow, now move your hand away for the wall a watch what happens to the shadow it becomes softer and less defined). Also the edges of the shadows in Terragen are two hard; there is much literature out there on shadow edges. 

And any thing else that people more familiar with GI renders then I could list as currently MIA.

if TG2TP really dose have true GI where is the look that both GI and Renderosity have it seems to be missing (or am I missing some thing?).

Also talking of shadows would it be possible to have Samples for the shadows to improve shadow quality as I have noticed errors there some times?

Regards to you.

Cyber-Angel   

buchvecny

i dont think there is way to lighten shadows, u may try selective color in photoshop ><

ProjectX

Best things I can think of are:

1. adjust gamma correction and contrast

2. Increase the global lighting brightness and lower the sunlight brightness (lowering the sunlight brightness offsets the increase in brightness from global lighting)

3. Lighten the surface shaders a bit (worst-case scenario)

Volker Harun

Hi,

if you want to have a look at the following image:


I gave the environmental light a higher impact on surfaces. I might correct me tommorow - when having a closer look at the tgd-file - but I remember to have set the environmental-light-colour to a darker tone for fine-tuning (at least I played with this setting).

In fact, the final image got a bit darker in photoshop then the render was.
Volker Harun

Cyber-Angel

There use to be a shadow lightness slider in 0.9.43, having it returned doesn't seem like to much to ask dose it, unless there are technical reasons why such a feature would not work with the current renderer?

Regards to you.

Cyber-Angel 

gradient

@Jay;
I've been having the same trouble....My workaround to this (and I've used it in almost all my TG2 renders so far) is to add a second sun directly opposite the original sun.  You will have to crank down the brightness of sun #2 substantially though because you only want to add a bit of brightness to the shadow areas.
The one big problem with doing this comes into play when you have a planet object...the light from sun#2 appears on the planet as well, producing a goofy appearance.  I haven't figured out how to eliminate the light from sun #2 from showing on the planet object...

Originally I tried to use a lightsource to achieve the same effect...but found that the light source just didn't produce enough strength or coverage....the sun did the trick though.

Oshyan

There are some bugs in the current GI system which cause unusually dark shadows in certain situations, for example when using Fake Stones. A global "shadow lightness" control is somewhat against the idea of Global Illumination when properly implemented, but it may be something we can support for convenience in the future. Certainly we will add additional control to the greatest degree reasonably possible.

In the meantime you can balance enviro light "strength on surfaces" and sunlight, use additional suns, etc. as others have suggested. There are a few workarounds, but I certainly agree they're not ideal from an ease of use and artistic standpoint. Another possibility would be to save an HDRI image as .exr and adjust it in Photoshop using levels to isolate the shadows.

I've also gone ahead and posted the Fill Light setup to the Shared Files area. I hope you find it useful. Instructions for use are in the post here: http://forums.planetside.co.uk/index.php?topic=580.0

C-A, I'm not sure what you would prefer us to be saying in regards to unimplemented features. We do our best to be clear as to what will be in the final product and that's really all the information that we can communicate at this point. I don't really see how the "fix it in post" analogy is relevant.

TG2's GI solution already supports color bleeding between surfaces. It's fairly subtle, as it is in the real world, and will often require high GI settings to be seen. But it is definitely in place and functioning at this time.

"Sample Resolution" is already handled by the existing GI detail settings, although perhaps differently than other solutions. I don't think you would complain that another GI renderer didn't have a "GI sample quality" setting though, so don't expect to always see a mirroring of familiar functions and settings in TG2. Solutions are implemented in the way that makes the most sense for TG2's specific needs and these often differ from more generalized systems in other applications.

We do intend to implement soft shadows in the future; it's definitely a noticeably missing feature in the current version. If you notice other problems or errors in the current rendering of shadows, please report them.

Gradient, Light sources need extremely high strengths at anything but the default size because the strength is proportional to light source size. Light sources do have falloff though, unlike the sun, so they'd be the preferred approach, especially in scenes with additional planets - a light source would not affect a far off planet.

- Oshyan

gradient

Thanks JavaJones.... I had already used very high strengths for the light source...around 800,000 or so...but I guess my source radius was still too small.
I will have to go back and try again with a larger radius.

buzzzzz

Wow! You all are giving me so many great ideas. I'll be sure to try them all at some point and I'll let you know which I used in the scene I'm putting together this minute. Tis a Great Group here indeed! Planetside Forum Rocks!

Thanks Gang!  ;D
Jay

buzzzzz

Update!

I just changed the Enviro Light Mode to "Ambient Occlusion" and it also seems to help lighten up the shadows. I hope I live long enough to get a handle on this?  ;)

Cyber-Angel

I was thinking about shadows in terragen and noticed some thing that is missing and really quite important for shadow realism and that is the phenomena of Penumbra and Umbra explanations for which can be found on Wikipeida:

http://en.wikipedia.org/wiki/Penumbra
http://en.wikipedia.org/wiki/Umbra

These are important phenomena and should be included in a future version of Terragen if possible.  ;D

Regards to you.

Cyber-Angel


Will

That or soft shadows will work...


Regards,

Will
The world is round... so you have to use spherical projection.

buzzzzz

Quote from: Will on January 25, 2007, 07:49:54 pm
That or soft shadows will work...


Regards,

Will


Will, is there a setting for soft shadows that I have overlooked?

Will

oh, no sorry I was speaking in responce to Cyber-Angel. Maybe increacing the GI sample but I don't know. Sorry I tend to confuse people.

Regards,

Will
The world is round... so you have to use spherical projection.