To create a curve on surface by drawing edit points

1. Double-click the New curve on surface icon, or choose Curves > New curve on surface r from the Curves palette menu.
2. Set Construction to Edit Point. Click Go.
3. Click the surface on which you will draw the new curve-on-surface.
4. Click to place the points of the new curve. You can move the new point while the mouse button is down. When you release the mouse button, the new point is added to the curve.
   • Click the to place a point.
   • Click the to place a point with the same U coordinate as the previous one.
   • Click the to place a point with the same V coordinate as the previous one.
   • Type a UV coordinate to place a point exactly.
   • Use snapping to snap to the nearest isoparametric curve intersection.
   • Use snapping to snap to the nearest edit point of a curve on surface on that surface.
   • Use snapping to snap to another curve-on-surface, or to an isoparametric curve.
   • If Curve Snap Intersections is turned on in Preferences > General Preferences (Modeling section), snapping will automatically snap a new curve-on-surface (CoS) to CoS-CoS intersections on the same surface.

To create a curve on surface by drawing freehand

1. Double-click the New curve-on-surface icon, or choose Curves > New curve on surface r from the Curves palette menu.
2. Set Construction to Sketch. Click Go.
3. Click the surface on which you will draw the new curve on surface.
4. Drag the mouse to sketch a curve on the surface.
5. When you release the mouse button, the sketch tool fits a curve to the line you sketched.
   NoteThe surface being sketched on must be of degree 3 or less.

Options

Construction

The method by which curves on surface are created.

Edit Point: click points on the surface to add edit points to the new curve.

Sketch: sketch the new curve on the surface freehand.

Curve Degree

The mathematical degree of the curve created, which control the number of CVs per span: 1 (linear) or 3 (cubic). The default is 3.

Knot Spacing

A “knot” is the parameter value of an edit point.Chord: the new curve’s edit points will be parameterized by the chord length of the curve.

Uniform: the new curve’s edit points will have integral parameters: the first edit point will be parameter 0.0, the second will be 1.0, and so on.