Check if the contours are polylines
To test to see if the contours are polylines, double
click on the line. If the whole contour is selected,
then the line is a polyline, if only a portion is
selected, then the contours need to be converted in to
polylines. You can convert lines to polylines if you
have the full CAD module of Civil Designer or AllyCAD.
The Design Centre does not have the ability to convert
lines to polylines.
Set up a new project
Once the drawing has polylines, a new project is
created. The project will include the contour drawing
and a blank DTM file.
Once the project has been created, change to
Terrain mode (this can be done by either selecting the
Terrain icon on the modes toolbar or by selecting
Terrain on the Mode Menu. If Terrain is not on the
Mode menu, then you are already in Terrain Mode).
Convert the polyline vertices to DTM points
The next step is to convert the polylines, this is
done via the Model Menu › Polyline to DTM. There are
two options available: Indicate Polylines or Selected Polylines.
The Indicate Polylines allows you to select a polyline
and assign a height to the selection, each polyline is
done one at a time. For the second option, Selected Polylines, you must select the polylines that you want
to convert and then the program will convert all the
selected polylines to dtm points. The selected lines
will all have the same heights.
In this example, we will use the first option to
convert the polylines.
The above dialog appears, you have the option to give your points a
name, and assign a height for the dtm points. A
surface can also be selected, and the lines that are
created can either be Break lines or Feature lines. In
this example we convert generated lines as Feature
lines.
After clicking on the polyline, points will be created
and the dialog reappears with a different Point name.
Continue the conversion process until all the polylines have been
converted.
Once the conversion has been completed, the drawing
can be switched off, this is done by editing the
project and removing the link to the drawing.
Once the drawing has been removed from the project, you will be able to
see the points that have been converted from the
drawing. If there are portions that have not been
converted, the drawing can be re-attached to the
project and the additional info added using the
Polyline to DTM function.
The screen shot above shows the converted DTM points from the drawing.
Triangulate the model
The next step is to triangulate the DTM, so that the
contours can be generated.
Select the Model › Triangulate option.
Make changes to suite the project and click OK to continue.
Note that existing feature lines are preserved during the
triangulation.
Once the triangulation is complete some manual editing might
be necessary.
The next step is to show the contours. As can be seen
on the above screen shot, the contours generated from
the DTM points match the original drawing. |
