To Create an Internal Datum Plane
1. Click 
Style > > 
Internal Plane. The Datum Plane dialog box opens.
Style > > Internal Plane. The Datum Plane dialog box opens.2. Click the Placement tab.
3. Click the References collector to place a new datum plane by referencing the existing planes, surfaces, edges, points, coordinate systems, axes, vertices, or curves. You can also select datum coordinate systems or noncylindrical surfaces as placement references for the creation of datum planes.
4. If required, specify a value for Translation to place the new datum plane at an offset from the selected reference.
5. Click the Display tab. The following options are not mandatory.
◦ Click Flip to flip the normal direction of the datum plane.
◦ Select the Adjust outline check box to adjust the size of the datum plane's outline. The following options are available when you select Adjust outline:
▪ Select Size to specify width and height for the datum plane.
▪ Specify a value for the Width of the datum plane.
▪ Specify a value for the Height of the datum plane.
▪ Select the Lock aspect ratio check box to maintain the proportion between the height and the width of the datum plane.
▪ Select Reference to size the datum plane to a selected reference such as a part, feature, edge, axis, or surface.
▪ Reference collector—Displays the reference that determines the outline size.
6. Click the Properties tab. You can:
◦ Click 
to view information about the current datum plane feature in a browser.
to view information about the current datum plane feature in a browser.◦ Rename the datum feature.
7. Click OK to create the internal datum plane. This datum plane is active by default and is displayed with a grid. Style also displays the horizontal and vertical directions for the internal datum plane.