A path is the line (or other shape) along which shapes are lofted to create 3D Loft objects.
The Path constraint also lets you assign a line or other shape as a motion path. A motion path is a form of trajectory.
Get Path (Lofting)
A circle is lofted along a path to construct a tubular shape. Get Path chooses the path spline
You use Get Path as a loft creation method when you want the path to move to the location of the selected shape. For example, you use this method if you have created a shape at the exact location where you want the base of your loft object to be. You use Get Path to create a loft at that location.
Get Path causes the path shape to move and rotate to align itself with the first shape on the path:
- The first vertex on the path is located at the first shape's pivot point.
- The tangent to the first vertex on the path is aligned with the positive Z axis of the first shape.
- The local Z axis of the path is aligned with the local Y axis of the first shape.
- The local coordinate system of the resulting loft object equals the local coordinate system of the path after it has been aligned with the first shape.
Sometimes, aligning the tangent of the path with the positive Z axis of the first shape does not produce the result you want. You can flip the orientation of the path by pressing 
while getting the path. Pressing aligns the path so that the tangent to the first vertex of the path is aligned with the negative Z axis of the shape.