Why Fillet Is Not Working in AutoCAD?

Why Fillet Is Not Working in AutoCAD?

AutoCAD is a powerful software used for creating precise 2D and 3D designs. One of the most commonly used tools in AutoCAD is the Fillet command, which allows users to create rounded corners between two lines or objects.

However, there are times when the Fillet command may not work as expected. In this article, we will explore some common reasons why Fillet may not be functioning properly and how to troubleshoot these issues.

1. Incorrect Selection

If the Fillet command is not working in AutoCAD, one possible reason could be an incorrect selection of objects. To use the Fillet command correctly, you need to select two lines or objects that intersect each other. Ensure that both objects are selected before executing the command.

2. Overlapping Objects

Fillet may fail if there are overlapping objects in your drawing. When two lines overlap, AutoCAD may struggle to determine which object you want to fillet. To resolve this issue, try deleting unnecessary overlapping lines or trim them using the Trim command before using Fillet.

3. Insufficient Gap Size

The size of the gap between two lines or objects can also affect the functionality of the Fillet command. If the gap is too small, AutoCAD may not be able to create a filleted corner effectively. Increase the gap size by moving or extending one of the lines and then try using Fillet again.

4. Object Properties

Another reason why Fillet may not work properly is due to conflicting object properties. Ensure that both lines have compatible properties such as being on the same layer or having similar linetypes and lineweights. Incompatible properties can prevent the Fillet command from executing successfully.

5. Incorrect Command Syntax

AutoCAD commands require specific syntax to function correctly. If you are experiencing issues with the Fillet command, double-check that you are entering the correct syntax. The correct syntax for Fillet is as follows: FI > Enter > Select first object > Select second object > Enter > Specify fillet radius or press Enter for a default value.


The Fillet command in AutoCAD is a useful tool for creating smooth transitions between lines or objects. However, there are several factors that can cause it to malfunction. By ensuring correct object selection, resolving overlapping objects, adjusting gap size, checking object properties, and using the correct syntax, you can troubleshoot and resolve most issues with the Fillet command in AutoCAD.