To add a circular opening with an existing surface, use the following procedure.

Tip: To assist in adding openings to surfaces, you can first click the Edit Surface tool in the Tools group on the Surface ribbon tab.

This isolates the surface in elevation view. You can also create local coordinate systems and grids for this view. Once you have added surfaces, you can then click the Edit Surface tool again to commit the changes to the physical model.

1. On the Model ribbon tab, select the Circular Opening tool in the Create group.
   
   The Add Circular Opening dialog opens.
2. Enter the opening parameters:
   1. Type the Radius of the opening.
   2. Type the Number of facets to use for the regular polygon. This is used to approximate a circle.
3. Click OK. The dialog closes.
4. Click on any point on a surface. This will act as the center of the circle.
   Note: The center of the circle must be greater than the specified Radius from any edge, including edges of other openings. That is, the circle cannot touch or overlap a surface edge.
   The opening is placed in the surface.
5. Repeat Step 4 to place additional circular openings of the same size.
6. To stop drawing new openings, do one of the following:

   select the Circular opening tool again (or any other tool)

   or

   pres the <Esc> key