CIVIL DESIGNER Tech Tip

Convert Road Layer into a DTM Surface

This tech tip explains how to convert a road layer into a DTM surface.

In most cases the final road design road layer will be converted into a DTM surface, but any road layer may be converted if required.

A few tips before starting:

1) Name your roads layers

File Menu › Select Road File

Select the Road and then click on the Edit button.

Give the layers that will be used descriptive names.

2) Name the DTM layers

Settings Menu › Display Settings

Select Terrain, and then Surfaces. Give the surfaces you will use descriptive names.

Converting the Road

Alignment Menu › Horizontal › Cross Sections › Translate

Chainage - Start and Stop	Enter the first and last chainages of the portion of the horizontal alignment to be processed.
Transform road layer	Select the road layer containing the cross sections to be translated.
Store to terrain surface	Select the surface on which the generated points should be stored.
Suffix to add to names	Enter a single character suffix that will be added to the names of all generated points. This helps in identifying points at a later stage.
Translate... - Roads Model	Select this option to translate a road design into a complete triangulated DTM model.
Translate... - Batters only	Select this option to translate only the first and last two points in each section.
Translate...- By offset	Select this option (and enter the Left and Right offsets) to translate points between specified offsets.
Translate... - By point location code	Select this option (and enter the Left and Right PLC codes) to translate points between specified points in the cross-section.
Create lines on section as...	Check this option and select either the Break lines option or the Feature lines option to have lines automatically generated between the translated points. The generated lines automatically delete any crossing lines in the surface to which the cross-section is being translated.

Make sure the new road DTM is created in a surface that contains no data, otherwise the data in the layer will be replaced with the translated cross sections. (there is no dialog to warn the user that the data will be over written)

Click OK to continue.

The road will now be converted into a DTM surface. The original road design remains intact.

The new DTM surface can then be viewed in 3D.

View the New Surface in 3D

Change to Terrain Mode

Applications Menu › Terrain

Terrain Menu › 3D View › View

Base surface	Select the surface containing the line model that defines the ground surface.
Terrace surface	Check this option and select the surface containing the line model that defines the terrace surface in order to generate a dual surface model or fly path.
Eye height	Enter the height above the surface at which the fly path should be generated. Only available when generating a fly path.
View radius	Enter the distance ahead of the current position that will define the position being looked at. Only available when generating a fly path.
Speed	Enter the distance that the view position moves between successive frames. Only available when generating a fly path.
Acceleration	Enter the distance that the view moves between successive frames when changing direction (only available if the Path from road file option is not selected). Only available when generating a fly path.

Select the correct surfaces, the base surface is the ground DTM , the terrace surface is the road DTM .

Click OK to continue, the surfaces will then be displayed in 3D. Various options are available in each section of the 3D view module, press F1 for detailed information.

Once the 3D view has been generated, different colours may be specified for each surface.

Once the new colours have been selected, click on the Apply button to view the changes.

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