You can identify a point in 3D space either by using the Point 3D CoPilot CoPilot, by entering the coordinates of that point directly into the command line, or by catching to existing geometry.

If none of these methods can be used, you can click the cursor directly in the viewport. In this situation, the clicked point is converted to a 3D position by projecting onto a corresponding plane which is parallel to the viewport plane. When selecting a point by a clicking in a viewport, Creo Elements/Direct Modeling attempts to use the defined catching behavior if possible.

The depth of the current point is then defined by determining the depth at which a normal through the previous point, if one exists, intersects the viewport plane. If no previous point exists, the computed point is located in the plane of that viewport, that is, the point has a relative depth of zero.