2D Meshes

A 2D mesh of elements can be generated in areas for which more detailed analysis is required. The created mesh is used to model 2D flows. See 2D Simulations for more details.

The 2D mesh is generated using the Shewchuk Triangle meshing functionality. Heights at the vertices of the generated mesh elements are calculated by interpolation from a specified ground model.

A bounding polygon must be defined in the network before a mesh is generated. Voids (regions that will not be meshed), break lines and areas of varying roughness and mesh resolution may also be defined.

See the Creating 2D Meshes topic for details on mesh generation and the objects used in mesh generation.

Apply rainfall profiles to 2D meshes

Rainfall profiles and their corresponding evaporation profiles can be applied to the elements in a 2D mesh in a network.

To apply a rainfall profile to a 2D mesh, select the Apply rainfall etc directly to mesh elements option for the 2D Zone in which the mesh is generated.


If 2D meshes and subcatchments overlap, rainfall will be applied to both subcatchment and 2D mesh independently by default. To prevent applying rainfall twice, set the Apply rainfall etc option to outside subcatchments to restrict application of rainfall to elements whose centroids are outside subcatchment boundaries.

Specify the rainfall profile to be applied to the mesh elements in the Rainfall profile field of the polygon. If a valid rainfall profile ID is not specified, the following action is taken when the simulation is run:

When using a rainfall event containing rain gauge boundary data, the rainfall profile is over ridden. InfoWorks ICM checks in which rain gauge region (if any) the centroid of each element is located and applies the rainfall profile to the element accordingly. See the InfoWorks or SWMM Spatially Varying Rainfall topics for further information.

Evaporation profiles in the event are applied to rain gauge regions as follows:

Resample 2D Zone mesh elevations

The ground level of mesh elements within selected 2D Zones in InfoWorks networks can be recalculated by sampling elevations from a different ground model to the one originally used during the meshing process. Re-meshing of zones is not usually required. This functionality may be used to calculate levels from a height corrected ground model for example.

  1. Select the Model | Meshing | Resample 2D zone elevations menu option to display the Resample 2D Zone Elevations dialog.
  2. In this dialog, select the ground model to be sampled.
  3. Click OK.

The resample process automatically validates the 2D Zone to check that there have been no changes since the mesh was created that could cause the resample process to fail. Such changes would typically include if a Mesh Zone or a Mesh Level Zone boundary has been edited or if a Mesh Zone or a Mesh Level zone has been re-named or deleted. If validation fails, the resample process is stopped and a message is displayed recommending that you correct the applicable objects before proceeding. When you click OK in response to the message, a list of validation messages that apply to the 2D Zone is displayed in the Output window. When you have updated the applicable objects, you can start the resample process again.

If the validation is successful, new ground levels for existing mesh elements will be calculated using the method described in the 2D Mesh Generation Methodology topic.

A resample log is automatically displayed and resample information is also appended to the Mesh summary field of the applicable 2D Zones.

Creating 2D Meshes

2D Simulations

Spatially Varying Rainfall

Spatially Varying Rainfall in SWMM Networks

2D Mesh Generation Methodology

Resample 2D Zone Elevations Dialog