What does the "FILLET" command do?

The "FILLET" command in AutoCAD is specifically designed to create a smooth, rounded transition between two lines or objects. When this command is executed, it generates a circular arc that connects the endpoints of the two selected objects, effectively merging them with a rounded corner. This is particularly useful in design and drafting where aesthetics and smooth transitions are important, such as in mechanical parts or architectural features.

By utilizing the FILLET command, users can define the radius of the arc, allowing for personalization of the curvature based on the design requirements. This functionality enhances the visual quality of the drawing and ensures that edges do not meet at sharp angles, which can be particularly beneficial in certain engineering and architectural applications.

The other options revolve around different functionalities in AutoCAD and do not accurately represent the purpose of the FILLET command. For instance, while creating an angle between two lines is related to other commands (like "ANGLE" or "LINE"), aligning objects along a curve pertains more to complex paths rather than simple fillets. Additionally, filling an area with color relates to various hatch commands instead of the rounding functionality provided by FILLET.