Edit Bezier Controls

Edit Bezier Curves

Bezier Curves may be edited by moving an individual vertex or a Control Point. The curve needs to be selected to present the vertices and control points for modification.

EazyDraw provides two flavors of Bezier Curve. This documentation applies to the Bezier Curve with no constraints for a continuous slope at each vertex. Use the Smooth Bezier Curve Modification documentation for curves drawn with the Smooth Bezier Tool.

Handles are used to move these points. The "Handles" are the small colored squares that are drawn on a Bezier Curve that is selected. The vertices Handles are tan colored. The control point handles are blue.

Modifying a Bezier curve is performed by moving vertices or control points. These points are moved with a mouse click and drag of a Handle. You need to click very close to the handle to "pick" it up for movement. The curve is redrawn as the picked point is moved. The operation is completed with the release of the mouse button which terminates the drag operation.

If a curve is selected and a click and drag is performed without hitting a Handle, the whole curve will be moved with the operation. If the Option Key is used this will also override a Handle select and the whole curve will be moved.

If the Command (Apple) Key is held down while a vertex is modified, the two control points for the curve segment ending at the vertex will move with the vertex. This process can help hold a curve’s shape while moving a vertex.

Each control point is associated with a particular vertex. When a control point is selected and moved a line is shown connecting the control point to its associated vertex. This is useful for complex curves when the association of a control point to a vertex might not be obvious from their positions on the drawing.

A Bezier segment is defined by the two end points and two control points. The curve locus and slope transitions smoothly from the start to the end with the starting and ending slope determined by the line to the associated control point. You may visualize the control of the curve by noting that the slope at the midpoint of the curve is parallel to the line connecting the control points, and that the curve is pulled toward the control line. This control line is shown in blue, connecting the two control points.

If an additional vertex is needed to fit a curve to the desired shape, they may be added using the Bezier Insert Tool or removed using the Knife Tool.