{"id":4972,"date":"2026-01-20T07:46:48","date_gmt":"2026-01-20T07:46:48","guid":{"rendered":"https:\/\/help.cadomation.com\/spcad\/docs\/spcadhelp\/lidar-tools\/clip-las\/"},"modified":"2026-03-12T08:11:13","modified_gmt":"2026-03-12T08:11:13","slug":"lasclip_sp","status":"publish","type":"docs","link":"https:\/\/help.cadomation.com\/spcad\/docs\/spcadhelp\/lidar-tools\/lasclip_sp\/","title":{"rendered":"Subset Lidar Data"},"content":{"rendered":"\n

Overview<\/h1>\n\n\n\n

Subset LiDAR Data<\/strong> clips a LAS\/LAZ point cloud to a user-defined boundary. The tool first shows the data extent<\/strong> in the drawing (displayed as a red outline<\/strong>) so you can confirm coverage, then you select (or draw) a closed polygon<\/strong> to define the area of interest. SPCAD creates a new output LAS file<\/strong> containing only the points inside the boundary. <\/p>\n\n\n\n

Access<\/strong> <\/h2>\n\n\n\n

LiDAR Tools \u2192 Subset LiDAR Data<\/strong> 
Command: LASCLIP_SP<\/strong> <\/p>\n\n\n\n

What does the Suubset Lidar Data do?<\/strong> <\/p>\n\n\n\n

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  • Lets you choose an input LAS\/LAZ<\/strong> file. <\/li>\n\n\n\n
  • Draws the LiDAR file extent<\/strong> in the drawing (red boundary) for visual reference. <\/li>\n\n\n\n
  • Prompts you to provide a clip boundary<\/strong>: \n
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    • Select an existing closed polyline<\/strong>, or <\/li>\n\n\n\n
    • Use Draw<\/strong> to sketch a closed polygon on-screen. <\/li>\n<\/ul>\n<\/li>\n\n\n\n
    • Clip the point cloud to the boundary. <\/li>\n\n\n\n
    • Prompts you to choose an output LAS file<\/strong> location\/name and saves the subset. <\/li>\n<\/ul>\n\n\n\n

      Workflow<\/strong> <\/h2>\n\n\n\n
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      1. Run LASCLIP_SP<\/strong>. <\/li>\n\n\n\n
      2. Select the input LAS\/LAZ file<\/strong>. <\/li>\n\n\n\n
      3. SPCAD displays the file\u2019s extent<\/strong> in the drawing (red). <\/li>\n\n\n\n
      4. When prompted, define the clip boundary: \n
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        • Select an existing closed polyline<\/strong>, or<\/strong> <\/li>\n\n\n\n
        • Type Draw<\/strong> and draw a closed polygon. <\/li>\n<\/ul>\n<\/li>\n\n\n\n
        • Choose the output LAS file<\/strong> path and name. <\/li>\n\n\n\n
        • SPCAD creates the subset LAS file. <\/li>\n<\/ol>\n\n\n\n

          Usability notes<\/strong> <\/h3>\n\n\n\n
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          • Ideal for extracting project\/site-area points<\/strong> from a large LiDAR dataset before: \n
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            • creating DEM\/DSM, <\/li>\n\n\n\n
            • building TIN surfaces, <\/li>\n\n\n\n
            • running tree\/building extraction, <\/li>\n\n\n\n
            • performing thinning or slicing. <\/li>\n<\/ul>\n<\/li>\n\n\n\n
            • The red extent preview helps you quickly verify that the LAS coverage matches your drawing area. <\/li>\n<\/ul>\n\n\n\n

              Tips<\/strong> <\/h4>\n\n\n\n
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              • Use a closed boundary:<\/strong> The clip polygon must be a closed polyline<\/strong>. If clipping fails, verify the polyline is closed and not self-intersecting. <\/li>\n\n\n\n
              • Keep the boundary within the red extent:<\/strong> If your polygon is outside the LAS coverage, the output may be empty or incomplete. <\/li>\n\n\n\n
              • Smaller boundary = faster output:<\/strong> Clipping a huge region can still be large; clip to the smallest practical area for better performance. <\/li>\n\n\n\n
              • Save with a clear name:<\/strong> Use naming like SiteA_Subset.las or Corridor_Clip.las to keep multiple subsets organized. <\/li>\n\n\n\n
              • Work in the correct coordinate system:<\/strong> The boundary should be in the same coordinate space as the LAS data. If the extent preview appears far away or scaled incorrectly, check your drawing units\/coordinate system setup. <\/li>\n<\/ul>\n\n\n\n
                Output<\/strong> <\/h5>\n\n\n\n
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                • A new LAS file<\/strong> containing only the points inside the selected\/drawn polygon. <\/li>\n\n\n\n
                • The extent outline<\/strong> is only a visual reference and does not modify the original LAS file. <\/li>\n<\/ul>\n\n\n\n
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