Basic Theory

This section defines the fundamental concepts and terminology of the Survey and Terrain Design Modules.

Civil Designer terrain modelling deals with three different types of information:

Terrain data, which consists of randomly ordered, irregularly spaced points that are directly defined in feature space by x, y and z ordinates.
Section data, which consists of ordered but irregularly spaced points that are indirectly defined in feature space by offset and elevation.
String data, which consists of 3D polylines, ordered in tree structures. When altering a string, its children strings are altered accordingly.

Any one set of terrain data is contained in a single data file. Any one set of section data is termed a Road or a Pipeline and has two components to it:

A file that holds the sections (offset/elevation pairs).
An associated design file that dictates the location of the above sections, how they are formed and other pertinent information.

There is interaction and regular data exchange between a terrain file and the section files. Several section files can be associated with any one set of terrain data, and that complete group of files is termed a project.

Several string file families can be associated with a terrain data file. The user will typically do a design using strings, and then transfer the string data to DTM data in order to generate contours, or to calculate quantities.

A typical project would have section files with ".nn.sec8" extensions, design files with ".nn.des8" extensions, a terrain file with a ".dt8" extension, and a file with ".DR4" extension that manages them. Note that the "nn" entry is a numerical figure from one upwards and is the road number in the job.

Various types of information can be used as input to design, build and maintain a Civil Designer job. Other types of information can be extracted by the program as end products, or to be used as input to other software packages. Most of the types of data described so far are specific to a particular job. However, there are also data files that are universal in nature and will have application in many different jobs. These can be thought of as Resource files. Typical examples are the sheet templates that control the form of your plotted output, and road templates that govern the way a road is formed.