Tuesday, April 16, 2013

Map 3D: Create Surface using LiDAR Data (point Cloud)

This tutorial will demonstrate the procedure to create a 3D surface using point cloud in AutoCAD Map 3D. To create a 3D surface using LiDAR Data in AutoCAD Map 3D, you will require the point cloud data as an  indexed point cloud data file.  

Step 1  Manage LiDAR data and create indexed point cloud data store 
  • To create a index file, choose the Index File tool from the Point Cloud panel of the Create tab; the Point Cloud Manager dialog box will be displayed.
  • In this dialog box, choose the Add File button.; the Open dialog box will be displayed. Next, browse and select the required point cloud data file(LiDAR .LAS, ASCII .xyz, or .point cloud .isd) in the dialog box and then choose the Open button; the selected file is added to the list in the Point Cloud Manager dialog box.
  • Next, specify the coordinate system for the selected file data file. To do so, click in the Coordinate System cell; a browse button will be displayed in this cell. Next, select this button; the Coordinate System Library window will be displayed. In this dialog box, choose the required CRS for the data file.
  • You can also filter the point data before creating an index file by applying data filters. To do so, click in the Filter cell in the Point Cloud Manager dialog box; the Filter Point Cloud dialog box will be displayed.  Use the options in this dialog box to define the parameters of the filter and then choose the Apply Filter button; the filter parameters will be applied to the selected point cloud file.
  • Next, choose the Generate Index button in the Point Cloud Manager dialog box. On generation of index, a green tick mark is displayed corresponding to the selected point cloud file name.
  • Next, choose the Add to map button; the selected file will be added to the drawing (If the data is not visible; then try using the zoom tools)

Step 2  Generating surface from the indexed point cloud data store file
  • Choose the Create from Point Cloud tool from the 3D Surface panel of the Create tab; the Surface Manager dialog box will be displayed.
  •  In this dialog box, add the indexed point cloud data store created in the previous step. To do so, choose then Add File button.
  • Next, specify the parameters for the surface to be created. To do so, click in the Parameters cell in the list of the Surface Manager dialog box. On doing so, the Grid Parameters dialog box will be displayed. Use the options in this dialog box to specify the required surface parameters and then choose the OK button to apply and close the Grid parameter dialog box.
  • Next, choose the Generate Surface button in the Surface Manager dialog box. On generating the surface, a green colored tick mark will be displayed against the selected point cloud index file. 
  • Next, choose the Add to the Map button to add the created surface to your drawing (use the zoom tool if required to zoom to the created surface )