on - turns motion blur on and off.
Duration (frames) - this value determines the number of frames vray takes into account when motion blur is computed for the current frame(the time when the virtual camera shutter is open).
Interval center - this value determines the center of the motion blur interval, relative to the 3dsmax frame numbering. The default value is 0.5, which means the the motion blur interval will be centered between two successive frames.
Low samples - this value controls the number of time samples that will be used by vray to estimate motion blur during gi calculations.
Geometry samples - this value determines number of geometry samples vray takes into account when blurring the current frame. A geometry sample is a mesh with a particular position at a given time. To calculate the motion blur effect vray assumes linear mesh transformation between several mesh positions (geometry samples).
When a mesh changes its position vray geometry samples are set linearly according to the duration (frames) value. note
: Vray assumes linear motion of mesh vertices from one geometry sample to the next.
Monte carlo sampling
min samples - the minimum time samples per image sample. Increasing this value produces smoother results at the cost of increased rendering times.
Max samples - this value determines the maximum time samples per image sample.
Threshold - when the color difference between neighboring image samples is greater than threshold value vray will take more time samples. The higher threshold value is set the less number of pixels will have great enough color difference to make vray take more time samples. This will result in fewer time samples and respectively more noise and shorter rendering times.
material min samples - this value determines the minimum number of material samples per face. Lower values will produce more noise, when used on detailed textures.
Material max samples - this value determines the maximum number of material samples.
Material threshold - see threshold in the above section
note: Analytic sampling is supported only for simple triangle meshes. The analytic method does not support some of the advanced geometry features of vray like displacement mapping and true instance rendering. You must use the monte carlo method if you want to use any of these features.