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Iain
10-13-2008, 02:32 PM
Inspired by my own partially successful results and some recent examples posted here, I've been trying to up the quality of my LW interiors.

The times are great and the light quality is good but in certain circumstances, I just can't get rid of artifacts (see at the ceiling joists in the attached).

This was using 2000 RPE and MIN PS of 1, MAX PS of 20.
I've tried everything from 250 RPE up and loads of MPS permutations and this is the closest I can get to a clean render.

Any ideas?

jameswillmott
10-13-2008, 04:48 PM
Oh I see, the little crackles along the edge where the joist meets ceiling... what are your secondary rays set to? Or are you just using one bounce?

Iain
10-13-2008, 05:01 PM
I've got 3 bounces and 50 secondary.

Messed around with that too but nothing seems to work.
(Think I've tried all the AA options too.)

jameswillmott
10-13-2008, 05:03 PM
Can you post the scene for us to play with it?

Weepul
10-13-2008, 06:08 PM
Try a higher secondary RPE (100-200) and/or a Min PS of 0.5...

MooseDog
10-13-2008, 06:52 PM
...when min and max come closer together the samples start representing more of a grid in relation to the camera. Setting them further apart allows samples to crowd around areas of higher importance and large even areas to have only a sparse distribution. But don't overdo it, 0.5-500 would be an unlikely setting for any kind of situation but the most unusual. min. PS is often happy anywhere between 1.0~4.0, and max MPS between 40.0~200.0. But do your own experiments...

maybe your mps's of 1-20 is too close a range, so the radiosity samples are not crowding close enough to the abrupt geometry changes between the ceiling and the beams.

Iain
10-14-2008, 03:41 AM
Thanks for the replies.

A combination of the suggestions from Weepul and Moosedog seem to do the trick but my render time has gone from the sublime to the ridiculous. And that's without some of the raytracing options enabled.

Exception
10-14-2008, 04:06 AM
Yes those kinds of geometry still remain an issue for the radiosity engine... however you could try your original settings and with monte carlo instead. if you're not using directional rays it is practically the same render speed but MC blends much nicer. It also avoids certain other issues FG has and is more physically accurate.

Let me know if that helped.

Iain
10-14-2008, 04:19 AM
Thanks Tom-I'll try that today.

Matt
10-14-2008, 04:47 AM
Iain I'm in the exact same situation here, I can't get rid of those horrible splotches and keep a reasonable render time.

For all the work done in 9.5 on the GI engine, it still needs a lot more.

This is why I still use FPrime, despite being as old as it is, I'm finding it still trumps the internal engine for these types of scenes.

Could be just my setups, but that's what I'm finding.

Iain
10-14-2008, 04:53 AM
Yep, I'm finding 9.3/9.5 to be amazing for certain things (flythroughs are a joy) but for quality sampling and contact details in stills I still rely on FPrime.

I'm happy to take a small hit in time for the accuracy it gives.

I experimented with full blown LW Monte Carlo for the first time in years when I got 9.5 and it was slower than Maxwell!

Exception
10-14-2008, 04:59 AM
iain, if you could let Mark G know about your problems maybe that will speed up the looking into issues like this. the kitchen scene's tiny artifacting issues are also still there, but I suspect its not being worked on because nobody has sent in a production bug report complaining about it.

Did you try MC? With direct rays off and use transparency off it shouldn't be much slower than FG but blend much better. If you have luminous geometry in your scene MC is also a better choice. I really don't use Fg anymore, and Mark has said he's considering throwing it out... it's still in there for backwards compatibility.

Iain
10-14-2008, 05:05 AM
Did you try MC? With direct rays off and use transparency off it shouldn't be much slower than FG but blend much better. If you have luminous geometry in your scene MC is also a better choice. I really don't use Fg anymore, and Mark has said he's considering throwing it out... it's still in there for backwards compatibility.

Oh-interesting :)

I've just tried MC and it was better. Much more natural so I'm going to raise the settings and try to get it totally smooth.

Thanks.

JeffrySG
10-15-2008, 10:21 AM
Are you guys using 'interpolated' when you use MC? I haven't been using it as I always though that the render times were much longer. I'll have to revisit it again! :)