AutoCAD - “Offset” Command #8 – “Offsetgaptype” variable

By Martin Phelps

How “Polylines” are “Offset” is determined by the “Offsetgaptype” system variable. Changing the value for this “System Variable” has no effect on standard “Lines”, “Arcs” or “Circles.

The default value is set to “0”.

1. Setting the value to 0.

“Extends” and “Trims” polyline segments to their projected intersections, as shown in Figure 1.

The inner most object is the original.

2. Setting the value to 1.

Applies “Fillets” to the “Polyline” segments at their projected intersections, with the radius of each arc being equal to the specified “Offset” distance, as shown in Figure 2.

The inner most object is the original. Each time the “Polyline” is “Offset” to the outside, the radius of the “Polyarc” increases by the specified “Offset” value.

3. Setting the value to 2.

Applies “Chamfers” to the “Polyline” segments at their projected intersections, the “Polyline” in Figure 3, has been “Offset” once to show the created “Chamfer”.

The inner most object is the original.

The resulting “Chamfer” may not be as expected, since the set “Offset” distance used to create the “Chamfer” is from the original vertex to the midpoint of the created “Chamfer”, so the length of the chamfer is not the specified “Offset” distance as shown in Figure 4.

If the “Polyline is “Offset” several times with this setting the results are shown in Figure 5.

Once the initial “Offset” has been created, each time the “Polyline” is “Offset” to the outside, two additional “Chamfers” are added, “Chamfering” the “Chamfer” as shown in Figure 6.