Wednesday, May 27, 2015

How to Export a Clipped GEOMAP Aerial Image

In this tutorial, I’ll demonstrate how to export a clipped GEOMAP image from Civil 3D 2015/2016 for use in other drawings and older versions of AutoCAD, MAP and Civil 3D.

1.   Create a new drawing containing Civil 3D surface styles.
2.   Zoom to the project location.
3.   Set the project coordinate system. For this example, my project is located in Virginia so I’m using VA83-SF for a coordinate system code.
4.   Turn on Map Aerial from the Geolocation tools on the Ribbon.

5.   Draw a box with even sides. To cover the project area, the box will be 10,000’x10,000’.

6.   Using the Geolocation tools, capture the area and snap to the adjacent corners of the box.

7.   Turn off the Map Aerial from the Geolocation tools on the Ribbon.

8.   Select the clipped aerial image and change the Resolution to Very Fine.

9.   Plot the drawing.
10.   Select a raster virtual printer. For this exercise, I’m going to select File-PNG.pc3.
11.   Click the printer properties button.

12.   Click the Add button.

13.   Click the Next button.

14.   Type 5000 in both width and height fields then click next.

15.   Name the new paper size then click Next. I’m going to leave the default name.

16.   Click Finish.

17.   Click OK to close the printer properties dialog box.
18.   Select the new Paper Size.

19.   Select Window from the Plot Area, What to plot: pull down.
20.   Snap to the adjacent corners of the 10,000’x10,000’ box.
21.   Click Apply to Layout and then OK.

22.   Save the image file to the project folder. (It may take a few minutes to plot the image.)
23.   Delete the GEOMAP aerial image.
24.   Reference the new aerial image into the drawing.
25.   Snap it to the lower corner of the 10,000’x10,000’ box.
26.   Scale the image to the same size as the box.

27.   Use Raster Tools to create a geo-referenced World File if needed.

If you have any questions, let me know.

Thursday, May 7, 2015

Adding Breaklines to a Civil 3D Surface

I see a number of Civil 3D users adding a surface smoothing edit to smooth contours. Surface smoothing often creates a very large TIN Surface (Triangulated Irregular Network) and CAD file. A construction contractor may also have a difficult time working with a large TIN and CAD file if used for Machine Control. Breaklines can be added to a surface to create a cleaner TIN and contour lines.

Here are the steps:
Once the breaklines have been modeled and are ready to be added to a surface, adjust the Supplementing Factors in the Add Breaklines dialog box. The following settings work well but adjust them as needed.

• Turn on and set the Distance to 10.00’.
• Set the Mid-ordinate Distance to 0.01’.

Below are the links explaining the Supplementing Factor Distance and Mid-ordinate Distance from Autodesk’s Help file.

Autodesk Civil 3D Help: Supplementing Factors

Autodesk Civil 3D Help: Mid-ordinate Distance

Below are images of a surface with the default settings.

Below are images of a surface with the adjusted settings. Additional editing may need to be added to smooth the contours.

Let me know if you have any questions.