Copyright Goodheart-Willcox Co., Inc. 412 AutoCAD and Its Applications—Advanced The PCEXTRACTEDGE command is used to extract an edge where two planar surfaces intersect. Access the command and hover the cursor over the fi rst planar surface. When the surface becomes highlighted, select the surface. Then, hover the cursor over a second planar surface that is adjacent to the fi rst and select the surface. The edge at the intersection of the two surfaces is extracted as a line. The PCEXTRACTCORNER command is used to extract a point where three planar surfaces intersect. Access the command and hover the cursor over the fi rst planar surface. When the surface becomes highlighted, select the surface. Then, hover the cursor over a second planar surface that is adjacent to the fi rst and select the surface. In the same fashion, select a third planar surface that is adjacent to the fi rst two surfaces. A point object is generated at the intersection of the three surfaces. The PCEXTRACTCENTERLINE command is used to extract a line along the center axis of a cylindrical object. Access the command and hover the cursor over a cylin- drical surface. When the surface becomes highlighted, select the surface. A line coin- ciding with the center axis of the surface is extracted. Point Cloud Sections Section objects, introduced in Chapter 14, can be applied to point clouds by using the SECTIONPLANE command. The Section panel in the Point Cloud contextual ribbon tab provides access to the orthographic section plane options. Picking the 2 Point option activates the SECTIONPLANE command. Once the section plane is created, you can use it to extract the lines forming the section of the point cloud. This is an alternative to using other point cloud extraction commands. To extract section lines, make sure that live sectioning is turned on for the section object. Then, select the point cloud and access the PCEXTRACTSECTION command. The Extract Section Lines from Point Cloud dialog box appears, Figure 15-11. This dialog box is used to specify settings for the extracted geometry. Selecting the Entire cross section option in the Extract area extracts geometry from the area in which the section plane cuts the point cloud. Selecting the Perimeter only option extracts geometry along the section plane perimeter. The options in the Output geometry area are used to set the layer and color assigned to the geometry and specify whether lines or polylines are extracted. If you are extracting polylines, you can set the resulting polyline width. The Preview result check box located at the bottom of the dialog box PCEXTRACTEDGE Ribbon Point Cloud Extract Extract Edge Type PCEXTRACTEDGE PCEXTRACTCORNER Ribbon Point Cloud Extract Extract Corner Type PCEXTRACT- CORNER PCEXTRACTCENTERLINE Ribbon Point Cloud Extract Extract Centerline Type PCEXTRACT- CENTERLINE PCEXTRACTSECTION Ribbon Point Cloud Extract Section Lines Type PCEXTRACT- SECTION Tolerance options Specify the type of extraction to perform Specify the object type to extract Layer and color settings Figure 15-11. The Extract Section Lines from Point Cloud dialog box.