similar to the AA issue i think there is no solution to do this…simply because you dont know in advance if a pixel will be touched by a motionblurred object…you need to sample FIRST to know
Use something similar to the universal settings… e.g. QMC AA with something like 1/8 subdivs, and leave the motion blur subdivs to 1. With these settings, on empty areas V-Ray will take just 1 sample, which is as fast as it can be. If you have an object, it will take more samples accordingly. Further on, the number of samples will depend on the noise, and thus on the object speed indirectly. You may need to use larger buckets though.
I had not thought that by increasing the subdiv AA we could have a beautiful MB even with his subdivs to 1
Thank you Father Chrismas
:arrow: automatically less motion blur or more quickly when the movement of camera or objects are on stop or very slow.
For when the min/max subdiv for MB?
:mrgreen: