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**flipside** · 10-02-2006, 04:23 AM

Mmm that looks very odd. 1 thing, higher adaptive amount means lower quality, not that it will help in this case but anyway.

Try to start from scratch with your lighting. First without GI, enable each light one by one. Then turn on first bounce and do some tests, then second bounce... Try to find which aspect of the lighting is causing the problem so you can narrow it down. Then find out which object or material is involved.

**DanielBrew** · 10-02-2006, 05:24 AM

Hi Richard,

It looks like the secondary bounces or the GI has been turned off for the second image. Notice how the areas that are lit with direct light are almost as bright but areas like the ceiling which rely more on bounced light are almost completely dark in the second image. I'd check for things like refractive caustics being turned off accidentally or 'from file' being checked instead of single frame in your LC settings. Also as a test try using 800 subdivs for your LC.

Dan

**dlparisi** · 10-02-2006, 05:48 AM

Not that this solved anything, but it appears someone else had the same problem....http://www.chaosgroup.com/forum/phpB...ght+cache+dark

**rjw** · 10-02-2006, 05:56 AM

Flipside, I think I have the logic right for the adaptive amount, I have it higher for the low quality, no??? or I'm I misunderstanding what you're saying?
Do you reckon it's with the lighting then? I'm baffled as it's the higher GI settings that are screwing it, so turning of GI should stop the problem but I'm not sure what I'll get from doing this? Just a bit confused, not questioning your skills, I know you rock with Vray. BTW I've checked all your tutorials, they are so good, big thanks + respect.
I'll try re-creating the file.

Dan, I checked what you said and I see what you're saying but I do have 2nd bounces on, refractive caustics is on. I'm not running from a saved LC or IR. I do have a saved LC (even though the setting it off) I'll kill the LC file and see, maybe it's reading it when it shouldn't???
Running a test with LC at 800 now.

Thanks for the help for both of you.

Richard

**rjw** · 10-02-2006, 06:05 AM

dlparisi,

Interesting thread, pity there was no real conclusion (except keeping LC under 1000)
Cheers,
Richard

**flipside** · 10-02-2006, 07:17 AM

Adaptive amount=0.9 results in lower GI quality and faster renders than adaptive amount 0.5 for example. But I misread your first post

I thought in your low quality list there was 0.85 instead of 0.95 hehe
But that will solve nothing...

Yeah my GI off suggestion is not valid too, it was more like a general note when trying to find any problem. Still check if it happens without secondary bounces too. If it is not, try different secondary bounces engines, than you'll be sure if it's the and LC problem or not for example and you can concentrate on that instead of fiddling with the ir map settings.

**rjw** · 10-02-2006, 08:55 AM

I did wonder if it was a DR problem but I'm replicating it with BB.

I've ran some test and LC at 800 is ok, 1000 bad.
With 2nd bounces off it ok too.

I'll run it at full res tonight at 800 but am worried it might look a bit flaky.
Any settings recommendations etc.. on either not using 2nd bounce (like multiplying primary?) or photomap, I've hardly used this. testing it now.

Strange problem as I've used LC at 1500+ many times.

Cheers all,

Richard

**rjw** · 15-02-2006, 11:22 AM

Stated getting problems with LC at 200.
Must be something up???
My deadline was today so used Photo map. looked shitty as I didn't have any test time. Turns out the design needs changing any way

I'm taking Flipside's advise and running multi renders isolating the lights to see if that's a light problem.
BTW I'm faking my sun with a directional light with vray area shadows. Is this good or should I use a vray light?

Do Max files ever get corrupt and need rebuilding? I'm a novice with Max

Cheers

**CRD** · 15-02-2006, 12:09 PM

I had a similar problem and traced the source back to a standard material. So make sure to check all your materials and not just the lights.

**rjw** · 15-02-2006, 12:23 PM

I was actually thinking about that. I do use some standard mats. Is this really bad practice?

Also my floor mat is a Vray mat with tiles in the diff channel. For some reason it doesn't look reflective, but reflection is 134.
I'm wondering if this mat is playing up.

sorry if I'm asking dumb questions

thanks

**gilpo** · 15-02-2006, 08:22 PM

rjw-
In regards to your floor material not reflecting, check in the options of the material if 'trace reflections' is checked. I had a scene once where every material got this turned off somehow. It drove me nuts trying to find the problem. I've had mixed luck with standard mats. Raytrace and Architectural are definte no-use mats. Make sure you don't have any of those.

I had your same problem with a dark scene and light settings. Turns out I had somehow duplicated my floor right on top of itself. On the lower settings, vray was able to correctly bounce light off of one of them and light the scene, but with the higher settings it got confused and didn't render the GI properly. So, you might check your scene for any coplanar geometry.

Good luck!

**paulison** · 15-02-2006, 08:54 PM

Ive had the same problem before and I think there are several causes. Vlado has mentioned in another thread something to do with the old "red dot" or spots in the scene effecting the light calculation. If it starts with bad values, the problem is compounded as more lighting calculations are done (higher settings make the scene look worse).

there are a few good threads/ tutes relating to this around the place.

standard mats are the main one, so convert the scene to vray mats. I think only certain kinds of standard mats cause the problem, but you should change them all anyway as from my experience standard mats dont receive the light/shadows correctly.

Geometry & light intersection is another thing to check. Make sure all vray planes and sphere lights do not cut through any objects. Also make sure there are no hidden omni lights in your scene (not 100% sure about this one)

make sure all colours (especially in glossies ) are all less than 255 in value. Cant remember if this has been fixed, but worth a try

I've also had this happen from geometry errors so if materials arnt the cause you could try rendering without any objects that you suspect may be the cause

Oh last one, if you have RPC's, make sure you turn off reflection for the car windows for example.

Hope something there helps you anyway! GL

**rjw** · 16-02-2006, 03:25 AM

Gilpo - I'll check the mat setting, I'm out of the office so can't do it now.
I'm pretty sure there's no dups/coplanar faces in my original file but it's all possible. I'm DWG Linking from a file (DGN) exported to DWG, so there could be something going amiss in the process. Usually fine though.

Paulison - interesting about the spots comment, when I ran it without 2nd bounces I did get a few black spots. I didn't know that about all non Vray mats, I did know that 'it's best' to use Vray mats, a bit vague! From now on nothing but. There could be one intersection with light + geometry, need to check. I think I have less 255 value colours, thanks for the tip though. No RCPs but, again the tip is welcome.

I have future deadlines with this project so it's worth me recreating the file from the DWG Link, check out for any bad modelling and recreate with all Vray mats. I really hope the problem will be flushed out, I don't mind keeping my LC @ 800

I'll post any conclusions and hopefully successes.
Thanks so much for the help.

Richard

**rjw** · 17-02-2006, 09:42 AM

ok I reckon I've sussed it.
there was a vray light plane that intersected another max plane.
Good news was that I didn't have to rebuild my file

Hopefully that's it!!!

Cheers all
Richard

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