To Create a Cropped Surface

1. Click Home tab Create Ground Data panel Surfaces drop-down Create Cropped Surface Find.
2. In the Create Cropped Surface dialog box, Crop Information section:
   1. Click to select the source surface to crop.
   2. Click to specify the crop area in the drawing using the selection window, by drawing a polygon, or by selecting objects.
      Note: If you use the select objects option, click inside the polygon you want to use. The specified crop area is highlighted.
3. Specify the new surface information:
   1. Specify a destination for the new surface. You can place it in a new drawing, in any existing drawing, or in the currently active drawing.
   2. Enter the surface name and description.
4. Depending on the type of drawing that you selected in the previous step, specify the destination drawing for the cropped surface.
5. Optionally, modify the surface style. By default, Autodesk Civil 3D applies the standard style to the created surface.
6. Click to assign a layer for the cropped surface.

If you chose to create a new drawing file for the cropped surfaces, this drawing is saved in the directory where the source drawing resides.