You start with a new unnamed scene when you open 3ds Max. You can also start a new scene at any time by choosing New or Reset from the Application menu.
You choose a system of unit display on the Units Setup dialog. Choose from Metric, Standard US, and Generic methods, or design a custom measuring system. You can switch between different systems of unit display at any time.
The System Unit setting, in the Units Setup dialog, determines how 3ds Max relates to distance information you input to your scene. The setting also determines the range for round-off error. Consider changing the system unit value only when you model very large or very small scenes.
Set spacing for the visible grid in the Grid And Snap Settings dialog 
Home Grid panel. You can change grid spacing at any time.
See Precision and Drawing Aids for information about the system unit, unit display, and grid spacing.
Viewport layout options
The default four viewports in 3ds Max represent an efficient and popular screen layout. Set options in the Viewport Configuration dialog to change viewport layout and display properties.
See Viewing and Navigating 3D Space for more information.
Save your scene frequently to protect yourself from mistakes and loss of work. See Backing Up and Archiving Scenes.
