No detail in shadows.

[treddie]

I mentioned this a way back but I still feel it is an important issue and I am trying to understand it better.  I positively LOVE the Terragen system and the atmospheric effects are simply the best bar none.  My only criticism about TG is that in every render I have seen to date, the foreground contrast is always way too high...the dark areas inside plants, the shadow sides of rocks, anything where direct light does not fall, the ambient fill light drops off too quickly and goes almost black resulting in almost total loss of detail in those regions.  Is this due to a limitation in TG or is it that everyone is not taking full use of photon bounces (or the equivalent method TG2 uses) possibly due to the resulting huge time needed to do the render?  The latter case is certainly understandable...it would not represent a limitation of TG2...the math is what it is.  If this case is correct, it would just be the old problem of never having the CPU power to do what you would like to do in a reasonable amount of time.

[Dune]

You could use one or two fill lights...

[treddie]

That could work, and if TG is anything like standard photography, reflectors and lamps would be used for fill light to cut down on contrast.  But even "quick" photography w/o artificial fill, has better response in dark areas.  Can TG2 overcome this with simply more photon bounces at the expense of longer render times?

[Volker Harun]

Of course you can use higher GI settings ... The first thing you rather want to do is to play with atmospheres.
The original settings of TG2 are almost like 10am in the Sahara desert ... photographies there would have very harsh shadows, too.

A slight overcast sky ... add a cirrus layer, give it a Cloud depth of 40 to 60 and set the Coverage adjust to i.e. 2.
This darkens the overall scene, increasing the exposure inside the camera will give lighter shadows overall.

Adding fog or playing with the atmosphere will give an overall glow, that lightens up shadows, too.

[Mahnmut]

In my case it´s at least partly a question of rendertimes,
because my PC is old and I can´t sleep whyle it runs.
my experience concerning tg-shadows is the following:
The lower the gi settings, the less light and detail in the shadows, but that setting adds heavily to rendertime.
"cheaper" is the "enviro light" .

In this example I increased its strength to only about 1.7 (instead of 1 default) , and what you see here is even slightly contrast-enhanced in Photoshop:

http://forums.planetside.co.uk/index.php?topic=10833.0

I think there is quite a lot of light and detail in these shadows.
One last point concerns flatscreens, I just recently got one, and now all images I made before seem to dark in the shadows.
So I think there must be ways to get proper shadows in TG, if your cpu is just a bit faster than mine.

Best regards,
Jan

[dandelO]

Also, camera exposure and envirolight strengths can be adjusted independently of the final GI quality settings.
A luminous, or reflector setup, like you mention, also does well at bouncing and brightening up shadow areas without needing to add lots of GI detail calculation time, I think you can easily get a good balance of detail over render time by just taking those extra couple of steps before hitting the render button. http://sites.google.com/site/d4nd310/tg2gi

[cyphyr]

Three things:
Higher GI settings (relitive detail is more important than quality)
Fill lights (take a look at oshyan's Fill Light tgc).
Up the camera exposure.
Save the render as an EXR and play with the levles in post.
Ok four things
Richard

[treddie]

Thanks everybody for your responses.  Great work too! 

So my original assumption was correct then...GI for absolute realism but at the expense of render time, and also artificial fill lights to "Stand in" for GI and cut the render times down.  I'll have to go back to some of my earlier demos and experiment with GI and just let it run for a few days to see what happens.

[FrankB]

regardless of all the tips to circumvent the "black shadow" tendency in TG2, I too think that the default effect of GI seems to be way too low compared to nature - especially the fall-off with distance seems slightly but notably too strong. Just subjectively, though, but still...

[treddie]

I think so, too, but the only other option is to default it to a higher GI level which means a lot slower render times for people just starting out with the program (or for ANYBODY with a relatively slow machine).  What I would give for one of those new 12-cores in a small 3-4 machine render farm!

[dandelO]

...default effect of GI seems to be way too low compared to nature...

Agreed.

I think so, too, but the only other option is to default it to a higher GI level which means a lot slower render times

Adding/reducing envirolight strengths doesn't really add to the render time and is the best way to brighten the GI up. What does add render time is higher GI settings in the renderer node because it makes the calculation more correct with higher settings. You can brighten up the GI effect by raising 'strength on surfaces/atmosphere', this way, you can have significantly brighter GI in your scene without adding to the final quality settings.

[treddie]

I'll try that out next.  I am running an over the top GI of "6" test right now in my TG2 Demo program.  I'll then run it again with your suggestion and make a comparison.

Thank you for the tip.

[PorcupineFloyd]

Try setting GI strength higher in light settings (not in render settings). Eventually, export image as .exr and adjust curves in Photoshop or GIMP.

[cyphyr]

I've been trying something else recently. Not fill lights but two (or more) Sun lights in the same place. One is set to use soft shadows (soft shadow diameter =50), the other is set to no soft shadow or a very small one (say 1). Sunlight strength is of course halved so that the two combined suns give out the same amount of light as normal. Results look interesting so far but I think it will be scene specific.
I'll post a pic if I come up with anything worthy
Richard

[PorcupineFloyd]

Some people also prefer to use two environmental lights - one GI with strength at 1 and one with AI with strength at 0.5 to lighten up the shadows. However, this method increases render times a little.