The CHAMFER command connects 2 objects with an angled line. It is typically used to represent a beveled edge on a corner, but it can also be used to extend 2 objects until they intersect.
In AutoCAD MEP 2025 toolset, CHAMFER only works on AutoCAD objects, such as lines, polylines, and 3D solids. It does not work on building systems objects, such as schematic lines, plumbing lines, or duct, pipe, cable tray, or conduit segments. To extend and connect these types of objects, use FILLET, EXTEND, or a combination of grips, snaps, and polar tracking.