leakage & splotches

[fraggle]

Hello,
I'm aware that it is a reccuring issues with Vray and that there is a lot of threads reagrding this particumlar items.

So we have applied all knows solution to date without result as you can see. The only method that works is to render with brut force engine!

Any other idea.

Thanks.

[3DMK]

Hello,
I'm aware that it is a reccuring issues with Vray and that there is a lot of threads reagrding this particumlar items.

The problem is detail.
This is a GI issue that affects ALL render engins...not just vray



So we have applied all knows solution to date without result as you can see. The only method that works is to render with brut force engine!

Any other idea.

Unfortunately brute force is the ONLY way to go in certain situations......Some scenes such as yours just won't work without it. I discovered that hard reality many times.

You should however be able to use LC for secondary bounces which will speed things up dramatically.

The trick with using BF is to make sure you have plenty of light sources for the GI to reach so the soulution is not too grainy [without having to subdivide too much.



Thanks.

Hope this helps

[vlado]

It seems like your hemispheric subdivs for the irradiance map are too low (you can also decrease the DMC noise threshold a bit).

Best regards,
Vlado

[fraggle]

thanks, unfortunatly, even with a hemisph subd for IR set to 50, I still get some splotch and the render time explode (as mush as brut force I guess)!
Left : hemisph subd =30 render in 1'22"
right : hemisph subd = 50 render in 2'38"

I may have to go up to 100 to get a good result and the render will never end!

[crazy homeless guy]

Under your Irradiance map rollout, and under the sub category of Advanced Options... what is your Interpolation and Sample Lookup set to?

Maybe try either 'Least Square Fit' or 'Delone' for Interpolation, and Overlapping for Sample Lookup. It may not be perfect, but it has made issues like this close enough for me in the past.

My HSph. subdivs is almost always set between 60 and 90.

[3DMK]

thanks, unfortunatly, even with a hemisph subd for IR set to 50, I still get some splotch and the render time explode (as mush as brut force I guess)!
Left : hemisph subd =30 render in 1'22"
right : hemisph subd = 50 render in 2'38"

I may have to go up to 100 to get a good result and the render will never end!

You may even need to go over 100 to get a good render!!! Often I get up to 200 subdivisions in a really complex scene....but that's not a problem as it's only the GI stage that slows down NOT the actual render stage.

You have to acept that render times & final quality are ultimately tied to the complexity of your scene....you CANNOT avoid the fact that highly detailed geometry & unevenly lit scenes [such as interiors] will ALWAYS require higher settings.
Remember that the default setting of around 30-50 subdivisions are often way too low to get a clean solution in a complex scene.


I would also suggest using detail enhancement if using IR.....at a radius of about 2-3 cm ...Detail enhancement is BF so you CAN have the best of both all worlds using this method. Irrad-LC-BF all being used in the same render.

Hope this helps

[fraggle]

here is a snapshot of the result with hemisph subd for IR set to 60! Will try the trick from 3DMK immediatly.

[vlado]

There's something else wrong with your settings... what is your "Adaptive amount" option in the DMC sampler settings?

Best regards,
Vlado

[fraggle]

Here are the full setup.
Keep in mind that we are using solidrocks plugin as our main goal is design no to make 3D, so we are not expert with vray render setup!

[Drawehn]

You could also try raising the number of Interpolation samples (underneath Hemisph. Subs) a little. It's a balance between smoothing out splotches and loosing details but it's worth a trying to find the right amount.

Also I found the quality of interior lighting strongly depends of the quality of your light sources. Avoid lighting the entire room just with vray light mat objects for example and use a few IES or vray lights with high subdivions (or both). Poorly lit rooms are always more splotchy.

[vlado]

Hm, these are not bad settings actually; if you like you can send that part of the scene to vray@chaosgroup.com and our support guys will help you out.

Best regards,
Vlado

[fraggle]

thanks,
however, there is plenty of light source in this scene, the room is only 30 meter square!
the problem should be somewhere else.

[sea2stars]

Unless I'm missing something, what kind of system are you running to require the number of light cache passes to be set to 24?

[vlado]

Unless I'm missing something, what kind of system are you running to require the number of light cache passes to be set to 24?

Not sure about fraggle, but for example, we have a dual Xeon X5660 system here in the office (24 logical processors).

Best regards,
Vlado

[fraggle]

dual x5650, 12 physical core, 12 logical, total 24.