Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: lacilaci on 2013-01-31, 20:49:20

Title: light samples
Post by: lacilaci on 2013-01-31, 20:49:20

Trying different values at different scenarios and I often see this behaviour... All at default just different lightsamples, note that both images are pretty much just ca. one minute initial passes and the scene is lit only by a HDRI image.

Title: Re: light samples
Post by: lacilaci on 2013-01-31, 20:52:06

Now I currently think that in both situations corona would in time converge to identical results and that it is just difference in priorities in sampling... But I might be wrong and I'd like to ask what's happening differently when using higher light samples... Just to be sure that it is nothing wrong going on... :)

Title: Re: light samples
Post by: maru on 2013-01-31, 21:11:49

You mean "light samples multiplier" or "Max. sample intensity"?

Title: Re: light samples
Post by: lacilaci on 2013-01-31, 21:14:53

multiplier. Max sample intensity is set to 50 in both cases...

Title: Re: light samples
Post by: Ondra on 2013-01-31, 23:19:54

you are using HD cache here, aren't you...?

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 07:48:09

I am. How it relates to light samples?

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 08:23:52

just in case it wasn't apparent from previous images...

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 08:57:48

And one more... this is a little noisy since it's PT+PT and pretty much only initial passes 64PTsamples, but the same difference should be pretty apparent and I'm afraid it wouldn't change in due process as it did not with HDcache.

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 09:22:22

Another thing... If I would consider a BiDir as some lead to what lighting/Brightness I should look for, then it seems that renderings with lower(2) lightsamples gets me very close to what BiDir renders... So I have no idea what's happening when using high lightsamples value with PT+PT or HDcache...

Now I'm fine with using 2 samples if I can cause its "20min vs 50min for 16samples in those renderings at 2000x1500" but there might be something wrong going on when you need to up the samples in certain cases...

Title: Re: light samples
Post by: Ondra on 2013-02-01, 11:29:23

HD cache can give you different random brightness in each try. Buf if there is a systematic difference in path tracing, then it is probably a bug. Can you please upload the scene?

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 11:45:46

well I can't but I'll recreate very simple scene with this effect apparently happening and will upload it here....

Title: Re: light samples
Post by: lacilaci on 2013-02-01, 16:27:23

lol, what actually happens if I turn lightsamples multiplier to 0,0? Cause it looks just pretty much the same but renders quite faster:D

Title: Re: light samples
Post by: maru on 2013-02-01, 16:34:17

I guess it makes sampling more uniform?

Title: Re: light samples
Post by: Ondra on 2013-02-01, 16:52:02

Quote from: lacilaci on 2013-02-01, 16:27:23

lol, what actually happens if I turn lightsamples multiplier to 0,0? Cause it looks just pretty much the same but renders quite faster:D

then only single light sample is used. Direct lighting then gets sampled mostly by path tracing.

Title: Re: light samples
Post by: Ondra on 2013-02-03, 21:53:32

Just as I've suspected, there is environment override active. The fakes are not fully finished right now

Title: Re: light samples
Post by: lacilaci on 2013-02-04, 08:04:59

Alright, I'll try to avoid it for now :)