Blotchy and yucky GI

except · Post by **except** » Thu Jan 31, 2008 1:13 am

I've been using Kray for a while so am aware of its basic operations... but for this scene I can't get the GI to become smooth no matter what.

It's a very dark scene that I pull out of darkness by saving to an HDR and then re-exposing. I always get these filthy walls.

I've tried high photon numbers with N values from 500 to 3000, FG rays from 300 to 2000, small prerendering percentage, big one, and so on...
can't get it solved.

Any hints?

Captain Obvious · Post by **Captain Obvious** » Thu Jan 31, 2008 3:02 am

Do you mean you used FG with min 300 max 2000? It could be that the adaptive sampling for the final gather is failing due to the low light level. If you set it to min 2000 as well, maybe that'd help.

What does the precomputed irradiance look like?

except · Post by **except** » Thu Jan 31, 2008 3:19 am

Precomputed looked fine in various configurations...

I've tried a high number of low rays too. It all just really doesn't matter any one bit. It's strange...

except · Post by **except** » Thu Jan 31, 2008 6:42 pm

Well, I can't solve this one.
I've tried everything I can think of. 50 test renders later I've changed the whole scene, put area lights in the windows, brightened the lights changed the surfaces tweaked all of Kray's settings, but it doesn't help one bit, except that it just doesn't look atmospheric anymore.

I've uploaded the scene here... www.except.nl/overig/uploads/Condo.zip
If anyone want to give this one a shot, please do. It's a copyrighted scene that's not supposed to leave the office, but I really have no clue how to tackle this.

except · Post by **except** » Thu Jan 31, 2008 10:17 pm

Nope... nothing helping.

I've got some geometry emitting light too (stepladder) for some odd reason.

Captain Obvious · Post by **Captain Obvious** » Thu Jan 31, 2008 10:27 pm

What happens if you do a non-cached path trace render?

except · Post by **except** » Thu Jan 31, 2008 10:47 pm

I would most likely be waiting until the end of the new millenium, no?
It looks fine in Fprime.

darickster · Post by **darickster** » Fri Feb 01, 2008 2:28 am

with minor adjustments i am reaching 42000 cells, which should be enough. Added a luminous dome to the scene, maybe luminous panels instead of area could be helpfull too, though i am no expert on the topic.

Using the 2 pass prerending in tailer, raised N to 3000, bigger precache distance going from 40% to 85% (think this one makes sure you get enough cells). Precache blur to 220%

probably you used all that and my dualcore is just sweating for nothing right now, really hope you find a solution..

cheers

ps: prerender looks clean to me already

there at 50000 cells in first pass alone, letting it cook now

upping trace corner distance, just in case.. paths to 1 though i am sure the model is watertight

except · Post by **except** » Fri Feb 01, 2008 3:47 am

Phew...

this is supposed to be for an animation. 7 minutes per frame max...
Kray is definately losing it here from LW itself and Fprime

I have no idea what precache distance or blur do...

except · Post by **except** » Fri Feb 01, 2008 3:50 am

Ah, just to aid anyone willing to test this... the wall has the KraySurfaceOptions shader applied to control the number of FG rays... in case you go nuts over that and hadn't realized...

acidarrow · Post by **acidarrow** » Fri Feb 01, 2008 5:10 am

Okay,

I removed the extra area light
Turned off the GL light (not sure if it mattered)
Removed luminosity from everything
Removed the kraypanel from the walls (left it on the plant)
Set tone mapping to gamma with 2.2 / 2.2
Picked the medium preset
Tweaked the AA settings (grid 2 and .2 on detection)

and did a render on my "not that fast" laptop.

The result is this
(Now, it doesn't look very good, the AA is pretty bad and the settings could use a boost in general, but I think the GI looks clean enough.)

except · Post by **except** » Fri Feb 01, 2008 5:21 am

That looks okay although its a bit hard to see... It's a lot darker than mine. Once you brighten it up the noise really starts to show.

The luminosity is only on stuff that actually glows (LED's etc)...
That area light is gone for me too...
Removing Kraysurface from the wall doesn't help
Tone mapping is only relevant if you render to non-hdr (which I don't)
And the AA is okay...

Boo, I don't understand

The noise really comes out when you do a 1440x800 render too.

acidarrow · Post by **acidarrow** » Fri Feb 01, 2008 5:27 am

Did another one, a bit brighter and post processed it to look a bit like the original, at least the light levels (I'm not sure what's going on on the right side).

EDIT: ok I'll try rendering at bigger res then.

except · Post by **except** » Fri Feb 01, 2008 5:35 am

I think I'm already seeing some blech between the couch and the painting...

You know what, there's a bumpmap on that wall.
Removing it makes it better (although not fantastic).

Edit:
Cleaning up the model helped a lot for me too, not so much with the noise but with weird lighting. The stairs were starting to emit light at some point and random areas would just be very bright all of a sudden. Most of these models are converted from sketchup and are not so perfect...

acidarrow · Post by **acidarrow** » Fri Feb 01, 2008 5:59 am

Also, apart from the bump, you had a gradient by bump on color which I think is buggy with kray. Anyway I also removed the bump from the wall and did a 1440 render and I think that wall is pretty clean now.

If you use lumi lights make sure they are a different part each.

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Blotchy and yucky GI

Blotchy and yucky GI