#1 2016-06-22 08:55:16

Syme
Member

Global Illumination Artifacts

I was experimenting with Tesseract recently, and while playing with some larger maps I noticed that there is some strange behavior with the global illumination. Not sure if it is a bug or a limitation of the algorithm.

Here is a screenshot

It is clearly visible along the wall leading to the far corner as a large blotchy pattern and a sudden transition to a plain light color at the end. Similar effects are visible on official maps as well, to a lesser extent.

My best guess is that it has something to do with the size of the shadow maps used for calculating global illumination, but I don't understand the algorithm well enough to really know what it is.

I have two questions:

Is this specific to my system and/or configuration? I can provide more details if you want.

If not, is there anything that could be done to mitigate or improve it? Small maps like "Complex" still look good, but it would be nice to be able to make and use larger maps.

Thanks,

Syme

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#2 2016-06-22 14:10:35

chasester
Member

Re: Global Illumination Artifacts

I dont see what your seeing. There are some setting for the gi but most of it is done on its own. Check to see what setting your gi is on. If your setting arent all the way up it could just be a hack to speed up the calculation. I have seen some weird errors with the gi but most of it is with light bleeding not artifacts. You can disable gi on a pre cube level I do believe.

Your tree looks very off, are you sure you set the mdl setting up right. Cuz it looks like its not casting shadows (or at least self shadows). Or maybe its just too bright of a green or too much spec, something's really off there :)

chasester

If you could circle the spots that you see, maybe I can figure out what you are talking about.

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#3 2016-06-22 16:12:04

ThaOneDon
Member

Re: Global Illumination Artifacts

hmmm that doesn`t look that bad, maybe needs a little adjustment yeah

but i think this is interesting... (1280x800 desktop res, default settings in latest build, map - ot)

https://s31.postimg.org/cdv7kekej/image.jpg

Last edited by ThaOneDon (2016-06-22 16:39:32)

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#4 2016-06-22 16:41:14

Syme
Member

Re: Global Illumination Artifacts

I suppose I should post a video to make it more clear, maybe on a simpler map. That map isn't mine, by the way. It was just the first one I noticed it on. I'll see what I can do when I have some time later today.

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#5 2016-06-22 17:10:36

Syme
Member

Re: Global Illumination Artifacts

Hopefully this video makes it a bit clearer what I'm talking about. If not I'll try to construct a better test case.

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#6 2016-06-24 02:09:58

chasester
Member

Re: Global Illumination Artifacts

https://www.youtube.com/watch?v=r2PV1YR … e=youtu.be

i made a lil video on how to fix the problem.

Last edited by chasester (2016-06-24 07:37:08)

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#7 2016-06-24 07:54:10

sesilla
Member

Re: Global Illumination Artifacts

Hi chasester,

the video is not available! :)

Regards
Sesilla

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#8 2016-06-24 19:11:57

Syme
Member

Re: Global Illumination Artifacts

Thanks chasester! I'll go take a look at those parameters.

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#9 2016-06-24 22:34:01

chasester
Member

Re: Global Illumination Artifacts

for your map 1024 or 2048 (if you modify the source) seems to fix it (at least in my mocked up version). Though I imagine the bigger the better, I Hardly noticed a frame drop (maybe a frame or 2) by changing this from the default 383 to the 4096 so maybe setting the default a little higher probably be better so that this popping doesnt occur :)

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