source: Innovyze Support Portal
When building a 2D model, updating the existing 2D surface is a common task,
- add more details to the surface, such as adding breaklines for road
- add proposed structures, such as new buildings, roads and ponds
In XPSWMM, you have a few choices:
- Updating the surface in a 3rd party software such as Civil3D or ArcMap
- Using a layered approach to combine a few DTM layers
- Adding breaklines and elevation shapes
Updating the surface in a 3rd party software such as Civil3D or ArcMap
If you are designing a project in Civil 3D, this will be the easiest way to get your updated surface into XPSWMM.
- In Civil3D, export your surface as a LandXML file
- In XPSWMM, import the LandXML file
In general, if you need to make a lot of changes to your surface, CAD or GIS has more powerful tools to get the job done.
Using a layered approach to combine a few DTM layers
For example, we need to add a pond to the existing surface.
- the existing surface is a flat surface at 10 ft
- the proposed pond is 10 ft deep
You can try the following,
- create a new DTM that shows the surface for the proposed pond
- then add it to your model, and make sure it is on top of the existing flat surface
For simple geometries, it can be directly created using the Build DTM tool. As shown below, we can easily define the pond using two rectangles
Adding breaklines and elevation shapes
A more advanced approach is to use the built-in tools to add breaklines and elevation shapes into the model.
First you need to create the layers under the Topography group.
For the same pond, you can use a fill area to represent the bottom, and a elevation shapes to represent the sides.
NOTE: the end results is a change of the elevation of the cell. Turn on the grid for better reference, the line should go through the middle of the cell to apply the changes.
Add a fill area from the bottom with elevation of 1.
add elevation shape for the 4 sides.
Below is the final result,
