To Create a Projection Circle
By using the Projection option, you can create a Constructed Circle by projecting a circle onto a plane. The plane must be parallel to the plane that the circle lies in, so that the projection is also a circle.
1. Click > 
Circle. The CMM Construct tab opens.
Circle. The CMM Construct tab opens.2. Select the parent reference Csys from the Parent Csys drop-down list.
3. Select Projection from the Type drop-down list.
4. Select 2 measure or construct steps in the following order:
a. First, select a measure or construct step of type circle to be projected.
b. Next, select a measure or construct step of type plane. The circle is projected on the selected step.
5. Click OK.