Curves have a start point, an end point, and a direction. You can use Curve Start/Reverse to change the direction of a curve or change the start point of a curve.
Changing the direction of a curve has a number of possible uses:
- to change the direction of a sweep in a swept surface.
- to change the direction of a curve in a surface.
- to change the direction of a curve as you are joining curves together.
Changing the start point of a curve is helpful for operations such as Ruled surface. The start points of the two curves are used to form a correspondence between the curves when the surface is created.