MotionBuilder uses the same render for both viewport display and file rendering. However, you can adjust various configurations to achieve relatively better quality in offline rendering.
You can choose different hardware anti-aliasing samples count for viewport and file rendering as shown in the following figure.
Advanced offline rendering effects can be achieved either by multi-pass or super sampling techniques.
The offline rendering interface in MotionBuilder 2014 is updated.
You can select the custom renderer and its preset, if available in the Render Using drop-down list for rendering an image sequence or video format. This can also be done using the SDK.