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Click on the z axis in the coordinate axis viewer to view the XY plane. Use the vertex selection tool and select a point on the top edge. Right below the model you will see the coordinates of this point. The y position is 4.98 mmm.
Right click on Named Selections and insert a new named selection. Change the Scoping Method to Worksheet.
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Click on Generate to generate the named selection. Rename it top y.
We will repeat the same steps to create a named selection for all the faces on the bottom edge of the model viewed from the XY plane.
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The y coordinate for the bottom edge is 3.3e-2 mmm. Rename the second named selection bottom y
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