When working on jewellery designs in Rhino, creating smooth, flowing curves is essential for capturing the elegant lines and contours of rings, pendants, bracelets and more. Here are some tips and techniques for drawing beautiful curves in Rhino:

1. Use control points strategically. When drawing a curve, place control points at the key locations where the curve changes direction. Avoid placing too many control points, as this can make the curve harder to edit. Aim for the minimum number of points needed to define the shape.

2. Adjust the degree of the curve. In Rhino, curves can have different degrees, which impacts their smoothness. A degree 1 curve passes through all control points, resulting in straight lines. Degree 3 is most common, providing smoothness while exactly matching the control points. Higher degrees allow the curve to deviate from the control points for greater smoothness. Experiment with different degrees to get the look you want.

3. Try curve creation tools. The Curve command allows you to click to place control points and enter to complete the curve. InterpCrv creates a smooth curve that passes through selected points. Use BlendCrv to create a curve that smoothly blends between two existing curves.

4. Edit control points. After drawing a curve, you can move, add or delete control points to refine the shape. Turning on control point visibility makes this easier. Making small, incremental adjustments usually works best.

5. Analyse curvature. The CurvatureGraph command provides a visual display of a curve's curvature at each point. Look for a smooth graph without sharp spikes or dips. The Curvature Analysis command for surfaces provides min/max radii and other key info.

6. Rebuild curves. If needed, use Rebuild to change a curve's degree and number of control points while keeping a similar shape. This can help smooth and simplify overly complex curves.

With some practice using these techniques, you'll be able to efficiently create smooth, precise curves that take your jewellery designs to the next level in Rhino. Aim to create curves that look fluid and graceful without unnecessary complexity. Well-crafted curves are the foundation of exceptional CAD jewellery models.