The options contained within the Modify>Fillet submenu can be used to add fillet curves either with trimming to a tangency, or without trimming.

When adding fillets, it will be important to keep the following in mind:

• In 3D construction mode, the program will attempt to create a plane from the selected entities. If both selected entities are lines, polylines, or vectors, then the program will always be able to create a plane. This plane will be at the depth of the first entity selected if the entities are at different depths with respect to this plane.

• If a plane cannot be created and the program is in 3D construction mode, a non-planar fillet curve will be created. If a plane cannot be created and the program is in 2D construction mode, an arc will be created using the active CPlane.

• You can trim or extend the selected curves to the intersections with the arc fillet. You cannot trim closed curves, such as circles, ellipses, or closed splines.

• You can trim or extend the selected curves to the intersections with the chamfer. You cannot trim closed curves, such as circles, ellipses, or closed splines.

To view information on a feature available from the Fillet submenu, click the appropriate link below:
Trim
No Trim