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Drawing Bézier curves

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Direct drawing of a Bézier curve

    DG10-33a.png Open the Curve toolbar by clicking on the small black triangle of the Freehandicon2.png symbol on the Draw toolbar. Click on the Curve icon Freehandcurve.png. The mouse cursor changes to Curvecursor.png.
DG10-33b.png Click on the start point of the curve and keep the mouse button pressed (start and end points are shown here in the figures as snap points).
DG10-33c.png Drag the mouse to approximately the position of your first control point. It does not matter if this is not exactly right as you can move the control point location later. If you hold the Shift key down while dragging, the control point will lie on a 45 degree grid.
DG10-33d.png Release the mouse button and move the mouse to the position of the end point of the curve. You can see that the line of the curve follows the movement of the mouse. Double-click at the end position.
DG10-33e.png Turn on point mode with the [[Image:]] icon from the Draw toolbar.

At the end of the curve you will see not only the end point but also an associated control point, the round handle. Hovering the mouse cursor over this point you can see that the cursor shape changes to show that you are in edit mode of a control point.

DG10-33f.png If necessary, now you can drag the control point to its correct position.

Drawing a succession of Bézier curves

Several lines or Bézier curves can be linked together. The single parts are referred to as segments. Technically such a succession of Bézier curves and lines is known as a path.

Begin the drawing as with a simple Bézier curve. At the end position of the first segment, end not with a double-click but rather with one of the following methods:

  • Click on the end point of the first segment but do not keep the mouse button pressed. In this way you produce a curve point which is both a control point for the first segment and a control point for the second segment. This control point lies however on the actual curve point and so does not influence the direction of the following curve segment. Move the mouse to the end position of the second segment. This segment appears to be a straight line but is in fact a Bézier curve. Either double-click to finish the curve or repeat the above procedure to add successive segments.

or

  • Go back and click once on the end point of the first segment and keep the mouse button pressed. Now you can, as at the start but now for the second segment, place the control point. Release the mouse button at the position of the control point and move the mouse to the end position of the second segment. The curve follows the line of movement of the mouse.

You can either end the drawing here with a double-click or continue and link in further segments.

To generate a closed curve, select the curve and click on the Close Bézier icon [[Image:]] on the Edit Points toolbar, or from the context menu select the option Close object.


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