How to Use a Compass in AutoCAD

The compass constructs geometry and describes direction.

A compass describes the world through the subdivision of a circle. There are two types of compasses: the tool for plane geometry and a method to define direction or orientation. Both types are important in AutoCAD, a computer-aided design (CAD) program that creates drawings on the computer. The plane geometry compass constructs a circle, so the circle tool is used in AutoCAD. Whereas, direction defines bearing angles for topographical surveys, and AutoCAD's Surveyor's Units use bearing angles.

Instructions

1. Open AutoCAD. Select "New" from the "File" menu to create a new project file.

2. Type "Circle" in the command line. Click your mouse at the center of your circle and type the dimension of the circle's radius. The circle acts as the plane geometry compass in AutoCAD.

   Type "Line" to draw straight lines. Click your mouse twice in the drawing window to define the line's two endpoints. The line acts as the plane geometry straightedge in AutoCAD.

   Use the "Circle" and "Line" tools in conjunction to draw the classical compass and straightedge constructions of plane geometry, including the bisector, regular hexagon and tangent lines.

3. Type "Units" in the command line and change the "Angle Type" to "Surveyor's Units." "Surveyor's Units" uses cardinal directions to describe an angle. For example, "N45d0'0"E" describes a 45-degree line, where "N45d0'0"E" means "45 degrees East of North."

   Change the "Base Angle Directions" in the "Drawing Units" window to move the azimuth of a compass for any other "Angle Type," such as "Decimal Degrees" and "Radians." By default, "0" runs "East" along the positive "X" axis. You can change the "Base Angle Directions" to any of the cardinal directions, such as "North."

References

• Autodesk: AutoCAD Services and Support

Resources

• Math Open Reference: Constructions
• Virtual Museum of Surveying: Index
• Autodesk: AutoCAD