Autodesk AutoCAD Map 3D 2014 Service Pack 1

Autodesk has announced the release of service pack for its Autocad Map 3D 2014. This service pack contains all updates from the Map 3D 2014 Hotfix1.

To download AutoCAD Map 3D 2014 Service pack 1click here.

To visit the support and service page for AutoCAD Map 3D click here.

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Rectifying Raster Data - Rubbersheet

This blogs discusses the transformation methods used to Rubbersheet Raster Images in AutoCAD Raster Design

 

When rectifying a raster image using the Rubbersheet tool in AutoCAD Raster Design, you can select either Triangular or Polynomial transformation method to transform the raster image. 

Triangular Image Transformation

In the triangular image transformation method, the raster image is divided into triangular regions using the user specified control points. Note that the Denaulay Triangulation method. is used for computing triangulation. Next, transformation is applied to each triangular area.  As a result this method produces much more accurate transformation than the polynomial image transformation method. 

Note that, this method applies transformation to that part of image which is within the area defined by the Denaulays triangulation. The portion of the image laying outside the triangulation is not transformed.  As a result, the Raster Design discards the image data outside the triangulated area which leads to the loss of data. To minimise the loss of data, ensure that the control points are placed as close to the image extents as possible. 

Polynomial Image Transformation

The polynomial image transformation method, transforms the entire images by matching the source and destination points as close as possible. Unlike the triangular transformation method, this method applies transformation on the entire image and therefore does not result in loss of image data. However, this method does not always result in perfectly matched source and destination points. The positional error between the actual destination point (destination point on transformed image) and the destination point specified by the user is given by:

Positional error = √ (∆x + ∆y)

Using this method, you can specify the polynomial degree in the Degree edit box corresponding to the Polynomial radio button. Note that the higher polynomial degree will increase positional accuracy of the image points at the matching locations (source point and destination points), but will increase in warping of the image at locations away from the control points.

To specify a higher polynomial degree you will require to specify a minimum number of control points. The minimum number of  control points for polynomial degrees are as follows:

Polynomial Degrees Minimum Number of Control Points

1 3

2 6

3 10

4 15

5 21

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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 )

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