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 2010/11/12, 64bit, Boxx technologies, dual quad core 2.8, nvidia quadro 4000, 20GB Ram, use mental ray for rendering, windows XP pro 64bit

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--