Use this procedure to crop linework or a profile-based object to a smaller area with a boundary you define. You can crop hatches, lines, polylines, arcs, circles, AEC polygons, mass element extrusions, spaces, and/or blocks. Neither the linework to be cropped nor the linework that defines the new boundary needs to have closed boundaries. For example, you can use a v-shaped polyline to crop a circle, or you can use a circle to crop a v-shaped polyline. Once you have begun the Crop command, you can also specify two corners of a rectangle to crop the linework or objects.
All of the originally selected linework outside the crop boundary is erased. If you choose to erase the crop boundary, boundaries are redrawn for any closed-boundary entities inside the crop area, but any open-boundary objects that have been cropped remain open.
Cropping a block with a polyline