grainy aluminum

[noobert]

hello guys,
I have a question about metal materials,
I have made a pretty good aluminum material, but when I render my scene the alu material is always very grainy, all other mats in the scene are no problem and very clear without any grain, so I think it has to do something with the material settings and not with the render settings, I have increased the subdiv. for glossy refl. of the alu mat up to 30(!), but it doesn't helps. If the camera is far away from the aluminium object, the grain doesn't matter but I want to make a closeup.
I have tried a lot to fix this, and also searched the whole forum for a solution....
If somebody has an idea please post it!
Thanx in advance!

Sorry for my bad english!

[Gijs]

Maybe post an image illustrating the problem and a screenshot of the material settings and render settings (incl. qmc). Then it can probaly be sorted out very easily

[noobert]

ok thank you for your quick reply!
here are my settings and my problem pic.







thanx in advance!

[Gijs]

My first guess is that the grain is because of the antialiasing settings. Try to render a small portion with -1 2 or even 0 2.

On the other hand, with almost all parts of your rendering being glossy, it will probably be faster if you render with simple two level or fixed. (see manual)

[percydaman]

ya -2, 2 is never a good setting to use for AA. I use minimum 0,2 for final renders.

[noobert]

I've tried 0/2 but the result is nearly the same as in the image above, later i will try simple two level, and let you know what's happend.

[noobert]

I've now tried simple two level, with following params.:
Base subd. 1 / Fine subd. 4/ Threshold 0,1/ Multipass checked /Rand unchecked, the result is still grainy, nearly as in the image above.
I am now trying fixed rate with 3 subd. and rand checked, but because the other ways haven't worked I think it has nothing to do with the AA settings (I am new to vray so this could be wrong). If anyone has another idea what could be the reason for the grainyness please post it. I am trying to get rid of the grain for 4 days now and slowly I am getting a little bit "grainy" too!

Thanx in advance!

[natty]

hi ..

try to increase the reflection depth ...its very low... i normally put mine to 10..

[noobert]

thanx natty!
but I've already tried that, this also doesn't make the grain disappear (I've tried it with max depth at 15 or 10 or 5 evrytime the grain doesnt realy change. I've also tried with/without "use Interpolation" checked).
any other idea

[percydaman]

how does it look if you set your Hsph and Interp settings to default? Maybe try 80, 30.

[Frances]

Natty wrote: hi ..

try to increase the reflection depth ...its very low... i normally put mine to 10..

Isn't this to do with levels of reflection? I don't see an explanation of this parameter in the help file. Seems like this would just increase render time (because the raytracer is looking for things to reflect in the reflected reflections of reflective objects) and not otherwise affect quality of the surface.

[natty]

You are right Frances... but it does make a big difference to reflection quility, especially on bigger scene's.

[noobert]

Hello again,
Hsphere subd. 80 and Interp. samples 30 doesn't help too
What could it be, I saw so much vray pics with realy smooth and clean metal in it ??? I just don't understand that my metal looks like it has a bumpmap in it! (...No there is no bump in it!)


But thanx for all your posts!!!
all suggestions are welcome!

[Frances]

Hello again,
Hsphere subd. 80 and Interp. samples 30 doesn't help too
What could it be, I saw so much vray pics with realy smooth and clean metal in it ??? I just don't understand that!

But thanx for all your posts!!!

Hi noobert,

What are the subdivs for your lightsource (in the Modifier stack)? Also, if this is a VRay light, is it stored in the IR map?

[noobert]

Hi Frances!
There are two vray lights with sampling subd. set to 10,
and one direct light with vray shadows applied and shadow samples set to 20.
I' am now trying it with 20 subd. for each vray light.....
By the way, I really like your works !