Units are the key to connecting the three-dimensional world of 3ds Max with the physical world. You define the units you want to use from the .
When you change display units, 3ds Max displays measurements in the new unit for your convenience. All dimensions are displayed in the new unit. Essentially, you’re using a new "measuring stick." No object is changed in this process. As in the physical world, objects in the scene maintain their absolute size, regardless of how you measure them.
When you enter any dimension, 3ds Max always assumes the number you enter is expressed in the current units. You can also enter a series of numbers: 3ds Max then converts their sum into the current unit. Here are some examples that assume the current units are in centimeters:
When you use US Standard as the display unit scale, you can select either feet or inches as the default for type-in entry. If you select feet and enter 12, the result is 12’ 0". However, if you enter 1’ 2, 3ds Max identifies the second digit as inches, producing 1’ 2" as the result.
3ds Max keeps track of all measurements in its own internal system unit. No matter what kind of display units you use, measurements are stored in this absolute unit for storage and computation. The default system unit is defined as 1.000 inch. As long as the system unit is left at one inch, you can freely share models and change units on the fly with no effect on the underlying geometry. Except in rare circumstances, you never need to change this default scale. This means you can merge a model created with any standard unit into your scene at true scale.
You can change the system unit setting on the System Unit Setup dialog, available from the . Changing the system unit is recommended only if your scene has very small (less than one inch) or very large dimensions. See for more information.