Error with cache irradiance and baking

[NiGMa]

Hi guys, its been a while (checked last post was 2008!), I do not get much rendering work. Where is everyone getting there work from, are you guys all freelance?

So, I found an error with kray in LW, there is some weird blurring applied by kray on wall polygon edges that are rendered with the camera mode: texture baker. This only happens with cache irradiance (CI) ON, I have attached images with it ON and OFF for you all to see. Is this a known problem? CI is much faster for me so I need to use it. Also CI is fine for a normal camera render, it is just when doing the texture baking, pretty sure this is a bug. I am using 2.56, tested on LW 8.5 (dont ask) and LW 11.6.3 both 32bit.

CI OFF - edges look good

CI ON - edges are blurry/messed up

spherical camera CI ON - looks fine

[Janusz Biela]

Everything is ok. Your Final Gathering setting is far from good quality.
You have two choices:
1. Use Uncache (QMC) but this is no interpolated system (only photon map is interpolated - but sampling GI: no) so will be noise and to reduce that you need long render.
2. Use Final Gathering with high settings. Also in Bake system in Kray you have special option for extending edges. It helps to reduce Final Gathering problems with sampling: as we know in Final Gathering everything is interpolated (why is so fast) it means, Photon Map and sampling GI has size. This affect going information about light into walls, behind corners. This is normal but it doesn`t mean we can not deal with this

If you have problems please upload scene here.

[NiGMa]

Hi Janusz,

I think you're missing the point, this is a bug, not a low gi problem, see attached.

1) I know I can use CI OFF, aka QMC, but renders take way too long and even if I use best noise removal software, it is still too long for my needs.

2) I have tried final gathering with high settings, 16000 rays even, but this does not remove the error, this is a bug not low FG settings. these splotches ONLY happen on the baked renders, not on normal camera render, therefore it is a bug of some kind. If you have a close look, on some walls it is fine (no blur/smear), then part way through the wall when another poly intersects it the blurring happens.

See image below:

The attachment intwalls_bake_tst2a00014-indi.png is no longer available

[Janusz Biela]

....still you have bad settings
This is not about rays per sample but also important is density of sampling, spatial tolerance, GI resolution, Path Passes corner distance....why I told you to post basic scene

[NiGMa]

Hi Janusz,

Yes you are right, the problem was minimum FG distance, when I put it really low 0.1% no more splotches or light leaks. See the attached image. This is great because now I have full control over kray, I can now finally do low accuracy GI but without splotches/error. Previously If I wanted to do low accuracy GI I would always get splothes and problems, now I can set min dist to 0.1% and put spatial tolerance at 0.5 (yes I know very high) and get very smooth and nice GI for animations.

If I want very good contact shadows even as good as QMC I can do very extreme settings, such as spatial tolerance 0.01 and min dist 0.01% and the contact shadows are just like QMC but still much faster! I now can use kray much more, this is very pleasing!

This makes sense since before the distances between the samples was much too large. So should the options section on the FG tab below the FG settings have a title Cache Irradiance settings (i.e. spatial tolerance, angular tolerance, min/max dist/etc)? This would be more helpful and explanatory for new users I think. I now understand these options are (they are CI), since for QMC these are disabled. BTW in the latest kray version the cache irradiance button works differently, must manually make the settings 0.0, CI button on general tab has no effect.

See! min dist: 0.1%, CI ON but with no black splotches, but still very inaccurate GI. Excellent for animation or fast renders!

[Janusz Biela]

This is minimum what you have to use in Final Gathering

But for Texture Baker I suggest use QMC setting (the same settings for Path Tracing). Is very simple, more min rays more quality:

the rest of the options do not work because they are for Final Gathering.

Here small hint: after render you can use Photoshop denoiser.
Here my experiments with Texture Bake animation, time render under 1 min/frame:

[NiGMa]

Yes I know I have used those settings you provided for years but they cause problems with splotches for me when poly are intersected and I don't want to spend a day fixing models that render fine in other renders. QMC has too long render times compared with CI for baking, I have 100's of maps to bake, cant batch them, otherwise I could use QMC, but as it is I have be here and click each time to start it, so its better if I can render each in a few mins. Also when I use denoiser it removes important bump surfaces so it is not a solution for me. But don't worry, I've found the solution, Janusz you should try very low min dist. 0.1% but high spatial tolerance e.g. >0.1 works great for low accuracy but not splotches/weirdness, maybe this only is good for baking.

I now have full control over kray and this makes me very happy! Now to get some work on Elance...