New update OB6.5 out today.

[fulvio]

Try using luminous settings treshold 0.1-0.01 Min100/max1000 or higher if it's still to grainy. By applying Limitdr to the luminous surface you should compress the dynamics a little bit and therefore less rays should be needed for a useful result.

Thanks again for Your advice. I'll try this settings and sorry for my questions,
I've find other useful discussions in the forum regarding the problem of the noise. The autoparts plug-in resolve a lot of my noise problems.

[silverlw]

We still dont have a proper manual and alot of functions is experimental so you have to ask. Im certain alot of others also benefit from this