I know there have been a lot of posts on this subject, but I think it is worth aking once more: is there any good way to get partially glossy reflections in Mental Ray?

Of course the problem is the speckly / grainy appearance of partially glossy materials when rendered from a moving camera path.  People who are used to my old scanline renders, now say the new ones I am doing with Mental Ray look like there is “dirt on the lens”. 

For the Arch&Design material, I have fiddled endlessly with the glossy samples setting, going up to 64 and getting somewhat better results but still unacceptable (and of course so much slower!).  I have tried using Fast Interpolate but it always renders with a pulsing / strobing appearance, even when used on flat boxy objects.  If I check “Highlights and FG only”, I lose the realistic reflection which is one of the best features of MR.

I have read about using a blurred environment map in the reflection slot, but for my type of work (arch. vis.) it is not an option as I need the scene objects (particularly window openings) to appear in reflections.

--3ds Max Design 2009 64bit, Direct3D 9, Win Vista Premium 64, 3ghz quadcore Xeon, Quadro FX1700--

I have read about using a blurred environment map in the reflection slot, but for my type of work (arch. vis.) it is not an option as I need the scene objects (particularly window openings) to appear in reflections.

@ Ivan, the Env Blur is good, but it only deals with environmental reflections.
@ Gary, as well as increasing glossy samples, the Sampling Quality settings can help with this. There are numerous threads on the subject here.

I have fiddled with the Sampling quality (I assume you mean on the MR renderer tab).  On my first MR project I used min 1 max 16; on my latest project I increased it to min 4 max 64 and the render times more than doubled (to about 30 min per frame on this machine) with only a slight improvement in the reflection speckles.

--3ds Max Design 2009 64bit, Direct3D 9, Win Vista Premium 64, 3ghz quadcore Xeon, Quadro FX1700--

have you precalculated you FG and GI throughout the animation? then used them as read only files for the final rendering? have you tried lower samples with a distance limit on the reflections? what about adjusting interpolation settings?

3ds Max Design 2010, 64bit, Boxx technologies, dual quad core 2.8, nvidia quadro 3700, 20GB Ram, use mental ray for rendering

Yes, I have pre-calc’d the FG...lighting and shadows are not the problem, it is definitely reflection.  The trouble with distance limit is, what I need to see the most are the bright reflections of objects lit by the sun / sky which tend to be the farthest things in and outside the building.  Interpolation settings only apply to Fast Glossy Interpolation, right?, which I have found to give horrible results (pulsating, strobing).

--3ds Max Design 2009 64bit, Direct3D 9, Win Vista Premium 64, 3ghz quadcore Xeon, Quadro FX1700--

Have you tried moving away from the Arch and Design materials and tried a dielectric Mental ray shader tree? or DGS?
Author: bgavares

NO!...I had actually not thought of trying a different material, oddly enough.  The reference is a little vague on those materials...can you tell me whether they render reflections using a different method?  It seems to be the “samples” method used in the A+D material that cause the speckles.

--3ds Max Design 2009 64bit, Direct3D 9, Win Vista Premium 64, 3ghz quadcore Xeon, Quadro FX1700--