Rhino defines curves by their control points, and the curve's degree. Users can change the number of control points, as well as their degree using the rebuild command.

Control Points

• A user can change the number of control points using the rebuild dialogue box.
• We'll start with a simple triangle. It has
  • 3 control points
  • Degree 1 (aka Polyline)

• By typing rebuild we open up the rebuild dialogue box.

• In the Point Count: section the number in () specifies the existing number of control points.
  • In the case of a triangle that is 3.
• In the Degree: section the number in the () specifies the curve degree
  • In the case of a triangle it is Degree 1, meaning it is composed of 3 straight line segments join'd together.
• Rebuilding to 6 control points with Degree 1 results in this.

• Note how there are 3 new control points at the midpoints of each edge.
• Rebuilding to 6 control points with Degree 2 results in this.

• Rhino is attempting to minimize the difference between the original curve and the rebuild curve, and locating the distribution of new control points accordingly.

<aside> 💡 Rebuilding will fundamentally change the shape of your curves. Use it carefully, particularly if you want to ensure different curve touch or intersect.

</aside>

• If we rebuild the above curve 6 more times, the form will drift closer to that of a circle. Each time the endpoints are being redistributed til a circle with 6 control points is formed.

• If we rebuild our circle to be
  • 3 Control Points
  • Degree One.