Drawing Polylines. Autodesk AUTOSKETCH 8

Drawing Polylines

A polyline is useful for drawing entities that have a fixed width, such as a wall in a floor plan. As you create each polyline segment, text boxes for the segment width and bulge appear on the edit bar. Polyline width is a realworld measurement, like the thickness of a wall. The Width of Segment text box allows you to create a tapered polyline segment by entering one width that is greater than the other. The constrain option forces both widths equal to the value in the Width of Segment text box.

The Bulge text box allows you to create a curved polyline segment. The value that defines a bulge is a ratio of two times the height of the bulge, divided by the length between its startpoint and endpoint.

Another way to measure the bulge factor is the tangent of one-quarter of the angle of the bulge. For example: for a bulge of 180 degrees, one quarter is

45 degrees. The tangent of 45 degrees is 1, so typing 1 in the Bulge text box yields a bulge of 180 degrees between the startpoint and endpoint of the polyline segment. If you enter the bulge as a numeric expression, AutoSketch calculates the trigonometry. For example, to calculate the bulge factor for a segment with a 180 degree arc, enter the following:

=tan(180/4)

You can substitute a different angle for 180 in the example above. For more information, see “Using Numeric Expressions” in online Help.

Each segment of a polyline can be edited individually. Selecting an existing polyline in your drawing allows you to edit its poly entity type and its width on the edit bar. For more information, see online Help.

Vertex editing allows you to change the shape of an existing polyline, and to add or delete vertices. For more information, see “Editing the Properties of a

Polyline or Polygon Segment” on page 305.

Drawing Polylines

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Tools for drawing polylines can be accessed from the Draw menu or the

Polyline toolset on the All-In-One toolbar. You can also activate the Polyline toolbar (which contains the same commands but can be docked anywhere on screen) by right-clicking a bar, then clicking Toolbars on the pop-up menu that appears. Simply check the Polyline check box in the Toolbars dialog box, then click OK to make the Polyline toolbar visible on screen.

To draw a polyline

1 On the Draw menu, click Polyline, Single, or click the Single Polyline button on the All-In-One toolbar.

2 (optional) Change the settings on the edit bar for start width, end width, and bulge.

3 Click a startpoint. A rubber-band line appears from that point.

4 Enter one or more additional vertices. Each one continues from the endpoint of the previous segment and begins a new segment. If you make a mistake, press DELETE to remove vertices one at a time in reverse order.

5 Right-click to complete the polyline.

In addition to regular polylines, there are four other ways of drawing polylines in AutoSketch: segment, perpendicular, corner and sketch polylines. Polyline Segment allows you to draw a single-segment polyline whose width, length and angle you enter with the keyboard. A perpendicular polyline is drawn at a right angle to a line, arc, circle, polyline segment, or polygon segment. A corner polyline creates a rectangle at the intersection of two polyline or polygon segments. A sketch polyline simulates “freehand” drawing. Sketch polylines are discussed in “Sketching” on page 141.

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Chapter 12 Polylines, Polygons, & Curves