Contour Generator
Pattern Generator
Function Editor
Tutorial

SecuriDesign Contour Generator

SecuriDesign Contour Generator is used to create a contour curve with variable offset. You use a function to define how the offset should be varied and the Contour Generator will create a mathematically precise curve that obeys your definition.

Contour curves are best suited to be used as envelopes to guilloche patterns produced by the Pattern Generator.


Contour Generator Dialog

When you launch Contour Generator by clicking "Contour" button on the SecuriDesign toolbar you will see the following dialog. Note, that you need to select the control curve first before you run the macro. The selected curve is used as base shape for the contour.

Note, it is recommended to use smooth curves for the control object of a contour. Try to avoid curves with sharp cusp nodes because they could produce poor quality contours. Also the control curve must have only one sub-path.

The following curve is used in the examples below as the contour control object:

The following parameters are available on Contour tab of the dialog:


Units

Specifies units of measurement for the following values: Amplitude, Offset, Pattern Len, and Period Len.

Currently the following values are supported: "in" = inches, "mm" = millimeters, "pt" = points.


Function

Specifies the function that is used to specify the contour offset variation. The functions can be designed in Function Editor.

The following examples show how different functions influence the shape of the contour curve:

Function = "Sin":

Function = "Loop2":


Frequency

Specifies how many periods of the function is used along the length of the contour.

Frequency = 10:

Frequency = 5:

See also Period Len parameter below.


Amplitude

Determines the amount of contour offset variation. The height between lower and upper maximums of the function is the amplitude.

Amplitude = 5 mm:

Amplitude = 3 mm:


Offset

Specifies vertical offset of the whole function relatively to the control object.

Offset = 0 mm:

Offset = +3 mm:

Offset = -1 mm:


Pattern Len

Displays the length of the control curve. This text box is for informational purposes only and cannot be edited.


Period Len

Shows the length of one period of the function. Increasing the function frequency automatically decreases the period length. In fact, period length equals to the pattern length divided by the frequency.

You can enter a new period length, if you need. However Contour Generator cannot create non-integer number of periods in the contour, so the closest integer value of the frequency will be chosen and the resulting period length will be adjusted accordingly.


Phase Offset

Specifies the function phase offset. This value corresponds to horizontal contour pattern offset. The allowed values for this parameter range from -100% to 100%. 100% meaning the horizontal offset of the whole period.


Outline Color

Specifies the color to the outline. If you want to use a specific color, put a checkmark in the check box and click the color button to pick the color for the contour curve outline.


Curve Quality

The contour curve is built as a set of small straight line segments. This value specifies how many line segments to use for a single period of the function. Thus, if you use the default value of 30 and build a contour with frequency value set to 10, then the resulting curve will consist of 30*10 = 300 straight line segments.

Increasing the curve quality value increases the precision at which the contour is built but it also takes longer to build and the resulting curve contains more nodes. Contour Generator will not create curves with more than 1,500 nodes. If the curve exceeds this limit, it will be automatically split into several pieces.


Smoothen Curves

When checked, this option allows Contour Generator to smooth curves so that they are no longer comprised of straight line segments, but rather of smooth curves. This further increases curve quality but takes even more time to build and sometimes may produce unexpected results when highly cusp nodes are supposed to be present in the contour curve.


Auto-Reduce Nodes

When this option is checked, Contour Generator will try to remove redundant nodes from the contour curve. This dramatically decreases the complexity of the resulting curve, but takes more time to generate the contour. This option is only available when Smoothen Curves is checked.


Group Curves

If this option is checked and a very long curve is produced so it has to be split in smaller curves, the resulting curves are automatically grouped. Otherwise they are left as separate objects in CorelDRAW document.


Preview

The image to the right of the dialog shows real-time preview of the contour curve with the parameters you've just entered. When you change the parameters, click the preview image to update it. The preview is not updated automatically, you have to click it when you finished modifying contour parameters.


The content of the Functions tab of the dialog is described in details in Function Editor section.

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Copyright 2002 by Alex Vakulenko. All rights reserved.
This page was last revised on 11/16/02.