Datum planes are used as references to place a sketch or a geometric entity. Datum planes are used as a reference on a part where a reference does not already exist. For example, you can sketch on a datum plane when there is no other appropriate planar surface.

Datum planes are infinite, but you can re-size the datum plane outline to fit a part, surface, edge, or axis. Alternatively, you can use the handles that are displayed to drag the boundaries of datum planes to re-size their display outline.

You can create a datum plane by specifying conditions that place it relative to existing geometry. To fully define a datum plane, you must select up to three placement references. Select the options to position the datum plane relative to the selected reference. The geometry types that you can select to create a datum plane are given below:

Depending on the selected reference, you can select the previous options using an Options Toolbar. When you create datum planes, names are assigned in sequential order (DTM1, DTM2, and so on). These datum planes are visible on the Model Tree.

To select a datum plane, you can select its name, select one of its boundaries, or select it on the Model Tree.