Race Track -- DupliFrames

4. Change the Bezier Circle to 3D
  •  Properties menu >> Object Data >> Shape tab >> 3D button
Note:
  • A Bezier Circle can be either a 2D or a 3D object. 
     
  • To use the Bezier Circle as a 3D path for the oval track, it has to be a to 3D object.
5. Add more control points to the Bezier Circle
  • 3D View menu >> Mode Box >> Edit Mode

  • 3D View menu >> Select >> (De)select All

  • 3D View menu >> Curve >> Segments >> Subdivide

Note:
  • Control points are used to shape the path of the race track
6. Shape the path of the race track
  •  To move:

    Select a center point.

    G key to grab.

    Move mouse

  • To shape:

    Select an end point.

    G key to grab.

    Move mouse

Note:
  • The Bezier Circle is a 3D object.   The shape can be changed on all 3 axis.  X, Y and Z.

  • Use the control points to shape it.  Add more control points if needed.