You can shorten or lengthen objects to touch the edges, projected edges, or extrapolated edges of other objects. This means you can create an object such as a line first and then later adjust it to fit exactly between other objects.
Objects you select as cutting edges or boundary edges are not required to intersect the object being trimmed. You can trim or extend an object to an extrapolated intersection; that is, where the objects would intersect if they were extended.
You can trim objects so that they end precisely at boundary edges defined by other objects. Cutting edges can be lines, arcs, circles, polylines, ellipses, splines, xlines, and rays. They can also be floating viewport objects in paper space. Wide polylines are cut along their center line.
In this example, you clean up the intersection of two walls smoothly by trimming.
An object can be one of the cutting edges and one of the objects being trimmed. For example, in the illustrated light fixture, the circle is a cutting edge for the construction lines and is also being trimmed.
When you are trimming several objects, the different selection methods can help you choose the right cutting edges and objects to trim. In the following example, the cutting edges are selected using crossing selection.
The following example uses the fence selection method to select a series of objects for trimming.
You can trim objects to their nearest intersection with other objects. Instead of selecting cutting edges, you press ENTER. Then, when you select the objects to trim, AutoCAD LT automatically chooses the nearest objects in the drawing as cutting edges. In this example, the walls are trimmed so that they intersect smoothly.
Extending operates the same way as trimming. You can extend objects so they end precisely at boundary edges defined by other objects. In this example, you extend the lines precisely to a circle, which is the boundary edge.
Wide polylines trim and extend so that the center line intersects the boundary. Because the ends of wide polylines are right angle corners, part of the end extends past the boundary if the boundary is not perpendicular to the extended segment.
If you trim or extend a tapered polyline segment, the width of the extended end is corrected to continue the original taper to the new endpoint. If this correction gives the segment a negative ending width, the ending width is forced to 0.