Detail in Deep Shadows (again)

[cyphyr]

Hi gang

I'm working on a scene of a deep canyon completely covered in tropical vegetation. The trouble I'm getting is that because the canyon is so deep (2km) large areas will always be in some form of shadow. I have tried a variety of ways to get rid of the flatness of the shadowed areas. The one that offers the best results so far is to have the GI prepass padding set to just 1 (GI relative detail = 3, GI sample quality = 2). This gives enough local detail about each tree/bush to remove their otherwise flat lighting. The trouble is that this also produces a fringe about each bucket section (look at the picture to see what I mean, horizontal and vertical dark lines)). I have tried many other variates of settings including multiple fill lights (up to , GI+AO and none produce the "look" I'm aiming for as well (its still got some way to go) as having a high GI setting and very low prepass.

FILE NAMING :~ this is version deepGreen10. The following numbers refer to the GI settings, so the first image, deepGreen10.3.2.1.jpg, has a GI relative detail of 3, GI sample quality of 2 and GI prepass padding of 1 and I'm using Ambient Occlusion instead of GI

So any bright ideas, this has stumped me for a week now.

Cheers

Richard

ps: the top of the two images below is the one thats nearer where I want to go but it has the bucket "fringes"
pps: bridge models are just standins
ppps: added another version, just raised the prepass to 2. Result the fringing is slightly less but so is the shadow detail

[TheBadger]

You know I cant help.
But I can tell you that this is a really cool shot! Its easy to tell that when you workout the technical issues, its going to look great. Please share the final image when your done if you are free to.

[FlynnAD]

What does the file look like if you take your 2nd version, the one with the overly-dark shadows, save it as an exr (32-bit), and increase the shadow curves in Photoshop? Does the detail come back (i.e. is the detail in the original render but simply too dark in the tg2 exposed rendering)?

[choronr]

I sometimes find that in certain situations, increasing haze density alone may brighten the objects and terrain.

[cyphyr]

I've not had much luck with exr's, they always seem to come out grainy, and its a little difficult to tell at the moment as this is only rendered at 0.6 detail and 3 AA so grainy is kinda built in.

Hmm just tried it on a new version. It brings out the detail ok (needs al lot more serious work) but also brings back the bucket fringing.

|If this was just for a still then I'd just whack up the settings and go away for a long weekend. Its not though, its going to be animated over about 1000 frames (details still to be decided but it is animated) so I'm trying to get over the issues that will arise earlier rather than later. Render time is about an hour but that will have to drom for the final (or at very least stay near the same once I start bringing the detail and AA quality settings up).

Cheers

Richard

[Hetzen]

That's a horrible scene to light Richard. The sun is infront of the camera, and there's some hard bounces for the GI to calculate down that raveen. Funnily enough I prefer the middle render.

Haze density and glow power can lighten shadows, although I'm not sure how helpfull it will be in this scene. EXR will certainly help stretch shadow detail with a curves effect. But this might just be an exposure setting if you don't want to use EXR. Otherwise maybe a low lumen fill light behind and off centre, and another stronger one towards the sun.

Good luck, because you'll definately get GI flicker when you render those 1000 frames without some artificial help.

[cyphyr]

That's a horrible scene to light Richard. ...

Yes it sure is and it get worse! Since the sun is so high a lot of the shadows will be cast from outside the camera FoV I'm going to have the ray detail region padding set high. Already tried on 1 and it took sooo much longer to render, gave up, but it will be necessary for animation. I'd use fill lights to avoid GI flicker but they just don't cut it with the shadow detail.

So if I don't use GI/AO I get horrible shadow detail, everything is "flat"
If I do use GI/AO then it only seems to work well with a very low GI blur radius (1, 2, 3) which for some reason gives these "fringed" buckets. At default 20 it offers no improvement over fill lighting. And of course if I have a low GI blur radius I'm practically guaranteed GFI flicker.

The animation will have the camera turning 180 degrees to look behind it so the lighting levels will change from full shadow to fully lit.

Ah well I like a challenge!

Cheers

Richard

[Hetzen]

You're right, but tbh the second set up in your initial post, I think would work better.

Have you rendered what it looks like at 180 degrees?

[cyphyr]

Not yet. I'm not anticipating the same shadow problems although the fully lit trees may also be overly uniform (flat) in their shading. I'll give it a go though, good idea.
Some of the best lighting I've had so far has been with the sun almost directly overhead, this way all the trees have a more rounded, less flat appearance (although looking either straight down or up may produce similar issues) and I wont get so many of those nice volumetric shadows. None of this is in any way finalised, it'll all change I'm sure before I even start animating I expect. This is more to figure out some solutions to problems I was expecting to occur, the unexpected stuff is still to come!
Cheers
Richard

[Hetzen]

I'd be tempted to keep contrast as high as possible Richard. Your foliage, god rays, and a good tracked lens flare mask will give you highlights in those shadows that will help keep interest over that length of animation. It might be useful to see where your scene is going over those 40 seconds. Maybe run a half pixel sized animation every 50th frame over night to spot any problems.

[Kadri]

I hear that the new Alpha TG2 has some new things . Do you use it Richard ?
If no ask Planetside. Maybe it might help.
Other then this did you tried different bucket sizes?

I would definitely try it with fill lights. In animation GI makes it very hard to use.
Use higher luminosity surface settings so you get less problematic dark places.
With this you will get faster renders and if you can put EXR outputs with these settings you could get away maybe.
Edit: You could use more lights-Suns with or without shadows to bring details out. No need for real world accuracy you know.

[TheBadger]

Also remember that when you animate, the motion blur will help to smooth out the lighting a bit. To a certain degree anyway, not including flicker.

[Hetzen]

You're not going to get much motion blur over 40 seconds.

[Kadri]

You're not going to get much motion blur over 40 seconds.

Why Hetzen? Is not only the time but the speed of the camera important too (from frame to frame)?

[cyphyr]

There will be some, the camera will be turning a full 180 in a relatively cramped place.
Richard