World Coordinate System

Up axis

Sets the up axis to Y or Z. The default is Y.

Working Units

The units in your preferences relate only to the current scene; you can change your current scene units without changing the default new scene units.

You can now specify default working units for new scenes ( File > New Scene > ). You can specify linear units, angular units, and time settings.

The units you specify are not overwritten when you open a scene file with different units. The first time you run Maya, the Default Working Units are set from the Working Unit values in your preferences.

Linear

Sets the unit of measure for operations that use linear values, for example, moving and scaling. The default is centimeters.

Angular

Sets the unit of measure for operations that use an angular value, for example, rotation. The default unit is degrees.

Time

Sets the working time unit for animation. The Time Slider displays time values in the unit chosen. The Time Slider values update when you change the time units. You can specify the time unit as frames or as clock values.

Frame selections include: 15 fps, Film (24 fps), PAL (24 fps), NTSC (30 fps), Show (48 fps), PAL Field (50 fps), NTSC Field (60 fps), 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 40, 75, 80, 100, 120, 125, 150, 200, 240, 250, 300, 375, 400, 500, 600, 750, 1000, 1200, 1500, 2000, 3000, and 6000 frames per second.

Clock values include: milliseconds, seconds, minutes, hours

The terms frame and time refer to working time units as displayed in the Time Slider. Technically the term frame applies only when Time is specified in frames per second (fps). In general, time can refer to frames or to clock values.

Keep keys at current frames

By default when you change the current time unit, the times for any existing keys are modified so that playback timing is preserved. For example, a key set at frame 12film changes to frame 15ntsc when the current time unit is changed to NTSC, since they both represent a key at 0.5 seconds. When this option is on, it leaves the key at 12ntsc that was originally at 12film. The default setting for this option is off. The option turns on once the current time unit is changed.

Tolerance

The Tolerance value determines the degree of accuracy that is maintained between the original and fit (or interpolated) curves. This setting applies globally to Maya. You can change it on a case-by-case basis. Set the following tolerance options:

Positional

Set the degree of accuracy between the actual positions of the original and interpolated curves.

Tangential

Set the degree of accuracy required to determine if two NURBS objects are to be made tangent across a shared edge or point.