Understanding and Using the EXTEND Command in AutoCAD

The EXTEND command in AutoCAD is a powerful tool for extending lines, arcs, and polylines to meet the edge of another object. This is particularly useful for creating clean and precise intersections between different geometric elements.

How to Use the EXTEND Command:

1. Start the Command: Type EXTEND on the command line and press Enter.
2. Select the Object to Extend: Use the selection tools to select the object you want to extend.
3. Select the Boundary Edge: Select the edge of another object to which you want to extend the selected object.
4. Extend the Object: AutoCAD will automatically extend the selected object to the intersection point.

Key Points to Remember:

• Object Selection: Ensure that you select the correct objects for extension.
• Edge Selection: The edge you select should be a valid edge for extension, such as the edge of a line, arc, or polyline.
• Intersection Point: The extended object will intersect the boundary edge at the closest point.
• Multiple Extensions: You can extend multiple objects to the same boundary edge in a single operation.
• Precision: The accuracy of the extension depends on the precision of the input geometry and the settings in the Units dialog box.

Example: Extending a Line to Intersect a Circle

1. Draw a Line and a Circle: Use the LINE and CIRCLE commands to draw a line and a circle that intersect.
2. Start the EXTEND Command: Type EXTEND and press Enter.
3. Select the Line: Select the line that you want to extend.
4. Select the Circle’s Edge: Select the edge of the circle where you want the line to intersect.
5. Extend the Line: AutoCAD will extend the line to the intersection point with the circle.

Additional Tips:

• Object Snaps: Use object snaps to accurately select endpoints, midpoints, and other geometric features.
• Dynamic Input: Use dynamic input to quickly specify distances and angles for precise extensions.
• Layer Settings: Ensure that the layers of the objects you want to extend are visible and unlocked.
• Complex Extensions: For more complex extensions, consider using the INTERSECT command to create intersection points and then using the TRIM command to trim the objects.

By understanding and effectively using the EXTEND command, you can create clean and precise geometric constructions in AutoCAD.