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How To: Get ArcView GIS to read the z-values in a CAD drawing

Summary

If the Z extent in a CAD drawing is less than 1 percent of the XY extent, ArcView GIS will not recognize the z-values. A two-dimensional theme is made instead.

Procedure

Add a new layer with a single feature whose Z extent is greater than 1 percent of the XY extent to get ArcView GIS to recognize the z-values.

  1. Open the CAD drawing in AutoCAD.
  2. Zoom to the drawing's full extent by navigating to View > ZOOM > Extents.
  3. Create a new Layer.
  4. Make the new Layer the Current Layer.
  5. INTERFACE METHOD

    A. Add a new line from the bottom left corner to the top right corner.

    B. Select the line and view its properties by navigating to Modify > Properties.

    C. Set the Z value of either the TO or FROM point to be greater than 1 percent of the XY extent. The DeltaXYZ values should help in this step.

    COMMAND LINE METHOD

    A. Use the EXTMIN and EXTMAX commands to determine the XY extents.

    B. Use the LINE command and enter the TO and FROM points. Make sure to specify the z-value for one of the points to be greater than 1 percent of the XY extent.

    C. Confirm the coordinate values with the LIST command.

    D. Turn the current Layer OFF so that it is not visible.

    E. Save the drawing as a new file or recompute the extents of the existing drawing.

    F. Open the drawing in ArcView GIS to confirm that the z-values are now being recognized.

    Note:
    If the drawing is being used in a three-dimensional scene, a large vertical exaggeration factor will need to be used to get a proper visual representation of the features in the drawing.