Maya Preferences
Important:
The import of Maya .ma & .mb files is only works for all versions up to and including Maya 2018. Therefore, Maya must be installed and the installation path set in the VRED preferences.
In the Menu Bar, click Edit > Preferences, then on the left side of the dialog box, select Import > Maya.
Import > Base
Maya Directory
Displays the path where Maya is installed. To change this, click 
, when browse to or enter a new Maya installation path.
Import > Loader
Force Grayscale Shadow Texture
Converts all shadow textures from RGB to grayscale textures.
Use Local Material Library
Uses the local instead of external material library.
Units
Sets the units to be used for imported data.
Export > Writer
Units (export option)
Set the units to be used for exported data.