Part Modeling > Datum Features > Datum Planes > About Modifying the Size of the Datum Planes
  
About Modifying the Size of the Datum Planes
Datum planes, by default, are displayed scaled to the model size. You can resize the boundaries of the datum planes or adjust them to selected references or specific values. You can size datum planes to visually fit a selected reference which is a part, feature, surface, edge, or axis. Alternatively, you can specify values for the height and width of the datum planes to expand the display outlines of the datum planes beyond the model outlines when you create or redefine datum planes. View the display outlines of the datum planes in Drawing mode.
 
* You cannot change the values of width and height by editing the datum plane dimensions.
The values that you specify as the height and width of the datum plane boundaries are not Creo dimension values and are not displayed. These values do not affect the regeneration of the model. Use the default_dec_places configuration option to set precise values.
Alternatively, you can also use the two-dimension outline handles to resize the display outlines of datum planes. A handle is displayed at each corner of the previewed datum plane when you specify the width and height values for the display outline of a datum plane.
You can lock the aspect ratio between the values of width and height such that a change in a value also changes the other value proportionally. When you drag one of the handles to change the height or width of the previewed datum plane, the values are automatically updated in the Width and Height boxes of the Display tab. The movement of the handle in the direction of the width or height is correspondingly restricted and the location of the mirrored handle is maintained as follows:
When you move the top right handle, the bottom left handle is not moved
When you move the top left handle, the bottom right handle is not moved
When you move the bottom right handle, the top left handle is not moved
When you move the bottom left handle, the top right handle is not moved
 
* The movement of the handle is restricted to a point when the value of the width or height is equal to its upper limit.
Model accuracy is maintained when the datum plane display outline changes. Creo may refit the display outline, if required.