Seeing what is Inside a Circle but not what Overhangs the Circle

[tsmith]

I have a portion of a drawing that must be seen inside of a circle. However the drawing extends past the boundery of the circle. In other words I have a graphic below a ROUND window. The space we could call the wall is white, the circle is clear and one can see a portion of a drawing inside the window. I can see how to create this if the window included horizontal and vertical areas but not when the window is a circle.

Any help would be appreciated.

And within 10 minutes of the above post I found how to perforn such a task. So I came back and edited my original post.
I created a circle with a line width of 15, line color white and no fill color. Then dragged it over the drawing to be hidden. Then create another circle with a width line of 1, line color of black and no fill color and drapped it over the drawing to be hidden. Centering each component to create a window properly on a white drawing.

Thanks for the suggestions.

tsmith

[wapperdude]

You have two solutions available.  One that I created, called Magic Window, see    
How to Clip or Mask a Circular Region on a Visio Page? , or one that Visio Guy created, see, Super Mask Visio Clipping ShapeSuper Mask Visio Clipping Shape.

Both should do exactly what you want.  My shape gives option of circular or rectangular plus transparency variations, Visio Guys is adds aribitrary shape I believe.