Drawing curves is done with the "Curve Editor" Panel. Select "Add Points" and then place points by clicking the left mouse button on the canvas. Each time a new control point is added to the curve, a new knot will be added to the knot vector.
Modes: All actions use the left mouse button.
Add Points: Allows you to add new points to the curve by clicking on the curve canvas.
Remove Points: Allows you to remove points from the curve clicking on a control point.
Translate Curve: Allows you to move the curve up/down and right/left.
Scale Curve: Allows you to increase the scale of the curve by dragging the mouse to the left. Decreases the scale of the curve by dragging the mouse to the right. Dragging the mouse up or down has no affect.
Move Point: By pressing down the mouse button over a control point and dragging, you may change a points position. This is also the method used to change the "weight" of a rational curve and the tangent of a hermite curve. This is accomplished by pressing down on top of the end of the tangent or weight line and dragging the mouse to a new location, then letting up on the mouse button.
Rotate Curve: Allows you to rotate the curve.
Translate, Scale, and Rotate operations demonstrate the affine invariance of these curves.