A surface definition is a collection of a surface build, data, and edit properties, as well as a list of the operations that you have performed on the surface. The type of definition data items that a surface can have depends on the surface type.
The Definition collection under a surface in the Prospector tree provides access to the surface possible data and edit definition items.
The data definition for a surface comprises the data components that you can add to a surface.
The following table illustrates the data categories that are supported for each surface type. If the surface type does not support a data type, the data type is not available in the surface Definition collection in the Prospector tree.
|
Category |
TIN Surface |
TIN Volume Surface |
Grid Surface |
Grid Volume Surface |
|---|---|---|---|---|
|
Boundaries |
Yes |
Yes |
Yes |
Yes |
|
Breaklines |
Yes |
No |
No |
No |
|
Contours |
Yes |
No |
No |
No |
|
DEM Files |
Yes |
No |
Yes |
No |
| Drawing Objects | Yes | No | No | No |
|
Point Files |
Yes |
No |
No |
No |
|
Point groups |
Yes |
No |
No |
No |
Data edits are operations that are not added to any of the existing data components; rather, they are added to a surface definition as edit operations.
The surface build process is incremental. Every time when you add data to a surface or edit the surface, the surface is updated. When data is removed, the surface is rebuilt.
To support the incremental build process, a surface has an operation list, which is a sequential list of all operations performed on the surface in its current state.
When you add point data to a TIN surface, the result can be affected by the order in which AutoCAD Civil 3D processes the points. You cannot control the order in which AutoCAD Civil 3D processes points in a single operation; AutoCAD Civil 3D adds points to the surface in an order that minimizes the time to perform the operation. The following are two ways the processing order can affect the resulting TIN surface:
The order in which surface operations are performed can impact the resulting surface. Because of the incremental way a surface is built or rebuilt (the operations are performed one at a time in the order that they appear in the operation list) the order of the operation list is very important. You determine the order by the sequence of the commands you use to define the surface data. You can later modify the order in the Surface Properties dialog box. The following is a suggested order: