Using point filters in three dimensions

You can use point filters when you work in three-dimensional space to locate points in two dimensions and then specify the z-coordinate as the elevation above the xy plane. For example, to begin drawing a line from a point with a z-coordinate 3 units above the center of a circle, insert the circle, and then start the Line command and respond to the prompts as follows:     

ENTER to use last point Follow <Start of line>: .xy

Select XY of: cen

Snap to centerpoint of: (select a point on the circle)

Still need Z of: 3 (locates the starting point 3 units above the center of the circle)

Length of line: (specify the length of the line)