Chamfer creates a curve that is a straight bevel between two parent curves.
Chamfer connecting two curves
When you turn on the Chamfer button, or while a chamfer curve sub-object is selected, a rollout with the Chamfer parameters appear.
The lengths are the distance from the intersection (or apparent intersection) at which the chamfer segment is drawn.
Length 1: The distance along the first curve you click.
Length 2: The distance along the second curve you click.
Some length values make it impossible to construct the chamfer. If you set the length to an invalid value, the chamfer returns to a default position and displays in the error color (orange by default).
These two areas let you control how the parent curves are trimmed. The controls are the same in each. "First" and "second" refer to the order in which you picked the parent curves.
Flipping the direction of a trim
Trim Curve: When on (the default), trims the parent curve against the fillet curve. When off, the parent isn’t trimmed.
Flip Trim: When on, trims in the opposite direction.
3DS MAX creates the chamfer curve. Changing the position or the curvature of either parent curve can change the chamfer as well.
The parent curves must be coplanar. The chamfer is not necessarily connected at the endpoints of the parent curvesyou can adjust its position with the chamfer’s Length parameters.