In order to have a smooth performance in the 3D View, your video card should have the following minimum specifications:

You can display a scale bar in the section views such as the 2D Line View, Arbline View and IL/CL View.

You can smooth 2D/3D volumes including velocity and other low frequency volumes using the Volume Smoothing process. This process uses the damped least-squares method to suppress derivatives in every spatial dimension of the input volume.