2D Surface Routing API

Collaboration diagram for 2D Surface Routing API:

Files
file	Api2D.cpp
	C API implementation for the 2D surface routing module.
file	Api2D.hpp
	C API implementation bridge for the 2D surface routing module.
file	NodeCoupling.cpp
	Implementation of 2D↔1D node coupling via orifice exchange.
file	NodeCoupling.hpp
	Orifice-equation exchange between 2D surface and SWMM nodes.
file	BoundaryData.hpp
	Structure-of-Arrays (SoA) storage for 2D mesh boundary conditions.
file	MeshData.hpp
	Structure-of-Arrays (SoA) storage for 2D triangular mesh geometry.
file	SolverOptions2D.hpp
	Configuration options for the 2D surface routing solver.
file	SurfaceStateData.hpp
	Structure-of-Arrays (SoA) storage for 2D surface routing state.
file	SectionHandlers2D.cpp
	Implementation of 2D input section parsers.
file	SectionHandlers2D.hpp
	Input section parsers for the 2D surface routing module.
file	MeshBuilder.cpp
	Implementation of mesh topology construction and geometry computation.
file	MeshBuilder.hpp
	Topology construction and geometry precomputation for the 2D mesh.
file	VertexReconstruction.cpp
	Implementation of pseudo-Laplacian vertex stencil construction and head reconstruction.
file	VertexReconstruction.hpp
	Pseudo-Laplacian vertex reconstruction stencil computation.
file	Default2DOutputPlugin.cpp
	HDF5 output plugin for 2D surface routing results (CF/UGRID).
file	Default2DOutputPlugin.hpp
	Built-in HDF5 output plugin for 2D surface routing results.
file	CvodeSurfaceSolver.cpp
	Implementation of CVODE wrapper for 2D surface routing.
file	CvodeSurfaceSolver.hpp
	CVODE (SUNDIALS) wrapper for the 2D surface routing ODE system.
file	SurfaceFluxCalculator.cpp
	Implementation of gradient computation, slope limiting, and edge fluxes.
file	SurfaceFluxCalculator.hpp
	Edge flux computation, gradient calculation, and slope limiting.
file	SurfaceRouter2D.cpp
	Implementation of the 2D surface routing orchestrator.
file	SurfaceRouter2D.hpp
	Top-level orchestrator for the optional 2D surface routing module.

Functions
SWMM_ENGINE_API int	swmm_2d_is_active (SWMM_Engine engine, int *active)
	Check whether the 2D module is active for this simulation.
SWMM_ENGINE_API int	swmm_2d_vertex_count (SWMM_Engine engine, int *count)
	Get the number of mesh vertices.
SWMM_ENGINE_API int	swmm_2d_triangle_count (SWMM_Engine engine, int *count)
	Get the number of mesh triangles.
SWMM_ENGINE_API int	swmm_2d_vertex_get_xyz (SWMM_Engine engine, int idx, double *x, double *y, double *z)
	Get vertex coordinates.
SWMM_ENGINE_API int	swmm_2d_vertex_get_xyz_bulk (SWMM_Engine engine, double *x, double *y, double *z)
	Bulk get vertex coordinates.
SWMM_ENGINE_API int	swmm_2d_set_vertex_z (SWMM_Engine engine, int idx, double z)
	Set vertex Z (ground elevation).
SWMM_ENGINE_API int	swmm_2d_triangle_get_vertices (SWMM_Engine engine, int idx, int *v0, int *v1, int *v2)
	Get triangle connectivity (3 vertex indices).
SWMM_ENGINE_API int	swmm_2d_triangle_get_area (SWMM_Engine engine, int idx, double *area)
	Get triangle area.
SWMM_ENGINE_API int	swmm_2d_triangle_get_centroid (SWMM_Engine engine, int idx, double *cx, double *cy, double *cz)
	Get triangle centroid coordinates.
SWMM_ENGINE_API int	swmm_2d_triangle_get_mannings (SWMM_Engine engine, int idx, double *n)
	Get triangle Manning's roughness.
SWMM_ENGINE_API int	swmm_2d_triangle_get_neighbours (SWMM_Engine engine, int idx, int *n0, int *n1, int *n2)
	Get triangle neighbour indices (-1 = boundary edge).
SWMM_ENGINE_API int	swmm_2d_edge_get_geometry_bulk (SWMM_Engine engine, double *length, double *nx, double *ny)
	Bulk get edge geometry — time-invariant edge length and outward unit normal components, indexed [tri*3 + localEdge].
SWMM_ENGINE_API int	swmm_2d_vertex_coupling_count (SWMM_Engine engine, int *count)
	Get the number of vertex-to-node coupling points.
SWMM_ENGINE_API int	swmm_2d_triangle_coupling_count (SWMM_Engine engine, int *count)
	Get the number of triangle-to-node coupling points.
SWMM_ENGINE_API int	swmm_2d_vertex_get_coupled_node (SWMM_Engine engine, int vertex_idx, int *node_idx)
	Get vertex coupling: which SWMM node is coupled to this vertex.
SWMM_ENGINE_API int	swmm_2d_triangle_get_coupled_node (SWMM_Engine engine, int tri_idx, int *node_idx)
	Get triangle coupling: which SWMM node is coupled to this triangle.
SWMM_ENGINE_API int	swmm_2d_get_depth (SWMM_Engine engine, int idx, double *depth)
	Get water depth at a triangle.
SWMM_ENGINE_API int	swmm_2d_get_head (SWMM_Engine engine, int idx, double *head)
	Get total head at a triangle (z + depth).
SWMM_ENGINE_API int	swmm_2d_get_coupling_flux (SWMM_Engine engine, int idx, double *flux)
	Get coupling exchange flux at a triangle (m/s, + = into 2D).
SWMM_ENGINE_API int	swmm_2d_get_rainfall (SWMM_Engine engine, int idx, double *rainfall)
	Get rainfall intensity at a triangle (m/s).
SWMM_ENGINE_API int	swmm_2d_get_net_source (SWMM_Engine engine, int idx, double *net_source)
	Get net source/sink rate at a triangle (m/s).
SWMM_ENGINE_API int	swmm_2d_get_depths_bulk (SWMM_Engine engine, double *depths)
	Bulk get depths for all triangles.
SWMM_ENGINE_API int	swmm_2d_get_heads_bulk (SWMM_Engine engine, double *heads)
	Bulk get heads for all triangles.
SWMM_ENGINE_API int	swmm_2d_get_coupling_fluxes_bulk (SWMM_Engine engine, double *fluxes)
	Bulk get coupling fluxes for all triangles.
SWMM_ENGINE_API int	swmm_2d_get_edge_flux_bulk (SWMM_Engine engine, double *flux)
	Bulk get normal edge flux at every edge of every triangle.
SWMM_ENGINE_API int	swmm_2d_vertex_get_head (SWMM_Engine engine, int idx, double *head)
	Get reconstructed head at a vertex.
SWMM_ENGINE_API int	swmm_2d_vertex_get_heads_bulk (SWMM_Engine engine, double *heads)
	Bulk get reconstructed heads at all vertices.
SWMM_ENGINE_API int	swmm_2d_get_max_depth (SWMM_Engine engine, double *max_depth)
	Get the maximum depth across all triangles.
SWMM_ENGINE_API int	swmm_2d_get_total_volume (SWMM_Engine engine, double *volume)
	Get total 2D surface volume (sum of depth * area).
SWMM_ENGINE_API int	swmm_2d_get_total_exchange_flow (SWMM_Engine engine, double *flow)
	Get total exchange flow rate (sum of all coupling flows, m³/s). Positive = net flow from 2D into 1D network.
SWMM_ENGINE_API int	swmm_2d_get_cvode_steps (SWMM_Engine engine, long *steps)
	Get number of CVODE internal steps taken in the last advance.
SWMM_ENGINE_API int	swmm_2d_get_cvode_last_step (SWMM_Engine engine, double *h_last)
	Get CVODE last internal step size.
SWMM_ENGINE_API int	swmm_2d_get_stat_max_depths (SWMM_Engine engine, double *max_depths)
	Get per-triangle max depth statistics (cumulative).
SWMM_ENGINE_API int	swmm_2d_force_rainfall (SWMM_Engine engine, int idx, double value, int mode, int persist)
	Force rainfall on a specific triangle.
SWMM_ENGINE_API int	swmm_2d_force_rainfall_uniform (SWMM_Engine engine, double value, int mode, int persist)
	Force rainfall on all triangles (uniform).
SWMM_ENGINE_API int	swmm_2d_force_coupling_flux (SWMM_Engine engine, int idx, double value, int mode, int persist)
	Force coupling flux on a specific triangle (override computed exchange).
SWMM_ENGINE_API int	swmm_2d_force_clear_all (SWMM_Engine engine)
	Clear all 2D forcings.
SWMM_ENGINE_API int	swmm_2d_get_dry_depth (SWMM_Engine engine, double *dry_depth)
	Get the dry depth threshold (m).
SWMM_ENGINE_API int	swmm_2d_set_dry_depth (SWMM_Engine engine, double dry_depth)
	Set the dry depth threshold (m).
SWMM_ENGINE_API int	swmm_2d_get_rel_tolerance (SWMM_Engine engine, double *rtol)
	Get CVODE relative tolerance.
SWMM_ENGINE_API int	swmm_2d_set_rel_tolerance (SWMM_Engine engine, double rtol)
	Set CVODE relative tolerance.
SWMM_ENGINE_API int	swmm_2d_get_abs_tolerance (SWMM_Engine engine, double *atol)
	Get CVODE absolute tolerance.
SWMM_ENGINE_API int	swmm_2d_set_abs_tolerance (SWMM_Engine engine, double atol)
	Set CVODE absolute tolerance.
SWMM_ENGINE_API int	swmm_2d_boundary_edge_count (SWMM_Engine engine, int *count)
	Get the number of boundary edges (edges with no neighbour).
SWMM_ENGINE_API int	swmm_2d_get_edge_bc_type (SWMM_Engine engine, int tri_idx, int edge, int *bc_type)
	Get boundary condition type for an edge.
SWMM_ENGINE_API int	swmm_2d_set_edge_bc_type (SWMM_Engine engine, int tri_idx, int edge, int bc_type)
	Set boundary condition type for an edge.
SWMM_ENGINE_API int	swmm_2d_get_edge_bc_head (SWMM_Engine engine, int tri_idx, int edge, double *head)
	Get specified stage boundary head for an edge.
SWMM_ENGINE_API int	swmm_2d_set_edge_bc_head (SWMM_Engine engine, int tri_idx, int edge, double head)
	Set specified stage boundary head for an edge.
SWMM_ENGINE_API int	swmm_2d_get_edge_bc_slope (SWMM_Engine engine, int tri_idx, int edge, double *slope)
	Get normal flow boundary slope for an edge.
SWMM_ENGINE_API int	swmm_2d_set_edge_bc_slope (SWMM_Engine engine, int tri_idx, int edge, double slope)
	Set normal flow boundary slope for an edge.
SWMM_ENGINE_API int	swmm_2d_set_edge_bc_tseries_name (SWMM_Engine engine, int tri_idx, int edge, const char *name)
	Set the timeseries NAME to drive a SPECIFIED_STAGE edge.
SWMM_ENGINE_API int	swmm_2d_get_edge_bc_flow (SWMM_Engine engine, int tri_idx, int edge, double *flow)
	Get prescribed flow per metre of edge (m³/s/m) for a SPECIFIED_FLOW edge. V-E4.
SWMM_ENGINE_API int	swmm_2d_get_edge_bc_cum_flux (SWMM_Engine engine, int tri_idx, int edge, double *cum_flux)
	Get cumulative boundary flux at an edge (m³, + = outflow).

Detailed Description

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Copyright

Copyright (c) 2026 Caleb Buahin. All rights reserved.

License\n MIT License

Function Documentation

swmm_2d_boundary_edge_count()

SWMM_ENGINE_API int swmm_2d_boundary_edge_count	(	SWMM_Engine	engine,
		int *	count
	)

Get the number of boundary edges (edges with no neighbour).

swmm_2d_edge_get_geometry_bulk()

SWMM_ENGINE_API int swmm_2d_edge_get_geometry_bulk	(	SWMM_Engine	engine,
		double *	length,
		double *	nx,
		double *	ny
	)

Bulk get edge geometry — time-invariant edge length and outward unit normal components, indexed [tri*3 + localEdge].

Output arrays must be pre-allocated to triangle_count * 3 doubles each. Local edge e is the edge opposite vertex e (matching the neighbour convention of swmm_2d_triangle_get_neighbours). Outward normals point away from the triangle interior. Provided so client-side velocity reconstruction from swmm_2d_get_edge_flux_bulk can run without re-deriving geometry from the vertex coordinates.

swmm_2d_force_clear_all()

SWMM_ENGINE_API int swmm_2d_force_clear_all

(

SWMM_Engine

engine

)

Clear all 2D forcings.

swmm_2d_force_coupling_flux()

SWMM_ENGINE_API int swmm_2d_force_coupling_flux	(	SWMM_Engine	engine,
		int	idx,
		double	value,
		int	mode,
		int	persist
	)

Force coupling flux on a specific triangle (override computed exchange).

Parameters

value

Flux rate (m/s, + = into 2D).

swmm_2d_force_rainfall()

SWMM_ENGINE_API int swmm_2d_force_rainfall	(	SWMM_Engine	engine,
		int	idx,
		double	value,
		int	mode,
		int	persist
	)

Force rainfall on a specific triangle.

Parameters

idx	Triangle index.
value	Rainfall rate (m/s).
mode	SWMM_FORCING_OVERRIDE or SWMM_FORCING_ADD.
persist	SWMM_FORCING_RESET or SWMM_FORCING_PERSIST.

swmm_2d_force_rainfall_uniform()

SWMM_ENGINE_API int swmm_2d_force_rainfall_uniform	(	SWMM_Engine	engine,
		double	value,
		int	mode,
		int	persist
	)

Force rainfall on all triangles (uniform).

swmm_2d_get_abs_tolerance()

SWMM_ENGINE_API int swmm_2d_get_abs_tolerance	(	SWMM_Engine	engine,
		double *	atol
	)

Get CVODE absolute tolerance.

swmm_2d_get_coupling_flux()

SWMM_ENGINE_API int swmm_2d_get_coupling_flux	(	SWMM_Engine	engine,
		int	idx,
		double *	flux
	)

Get coupling exchange flux at a triangle (m/s, + = into 2D).

swmm_2d_get_coupling_fluxes_bulk()

SWMM_ENGINE_API int swmm_2d_get_coupling_fluxes_bulk	(	SWMM_Engine	engine,
		double *	fluxes
	)

Bulk get coupling fluxes for all triangles.

swmm_2d_get_cvode_last_step()

SWMM_ENGINE_API int swmm_2d_get_cvode_last_step	(	SWMM_Engine	engine,
		double *	h_last
	)

Get CVODE last internal step size.

swmm_2d_get_cvode_steps()

SWMM_ENGINE_API int swmm_2d_get_cvode_steps	(	SWMM_Engine	engine,
		long *	steps
	)

Get number of CVODE internal steps taken in the last advance.

swmm_2d_get_depth()

SWMM_ENGINE_API int swmm_2d_get_depth	(	SWMM_Engine	engine,
		int	idx,
		double *	depth
	)

Get water depth at a triangle.

Parameters

idx	Triangle index.
depth	Output depth (m or ft).

swmm_2d_get_depths_bulk()

SWMM_ENGINE_API int swmm_2d_get_depths_bulk	(	SWMM_Engine	engine,
		double *	depths
	)

Bulk get depths for all triangles.

Parameters

depths

Output array (pre-allocated to triangle_count).

swmm_2d_get_dry_depth()

SWMM_ENGINE_API int swmm_2d_get_dry_depth	(	SWMM_Engine	engine,
		double *	dry_depth
	)

Get the dry depth threshold (m).

swmm_2d_get_edge_bc_cum_flux()

SWMM_ENGINE_API int swmm_2d_get_edge_bc_cum_flux	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double *	cum_flux
	)

Get cumulative boundary flux at an edge (m³, + = outflow).

swmm_2d_get_edge_bc_flow()

SWMM_ENGINE_API int swmm_2d_get_edge_bc_flow	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double *	flow
	)

Get prescribed flow per metre of edge (m³/s/m) for a SPECIFIED_FLOW edge. V-E4.

swmm_2d_get_edge_bc_head()

SWMM_ENGINE_API int swmm_2d_get_edge_bc_head	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double *	head
	)

Get specified stage boundary head for an edge.

swmm_2d_get_edge_bc_slope()

SWMM_ENGINE_API int swmm_2d_get_edge_bc_slope	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double *	slope
	)

Get normal flow boundary slope for an edge.

swmm_2d_get_edge_bc_type()

SWMM_ENGINE_API int swmm_2d_get_edge_bc_type	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		int *	bc_type
	)

Get boundary condition type for an edge.

Parameters

tri_idx	Triangle index (0-based).
edge	Local edge index (0, 1, or 2).
bc_type	Output: SWMM_2D_BC_WALL, SWMM_2D_BC_NORMAL_FLOW, or SWMM_2D_BC_SPECIFIED_STAGE.

swmm_2d_get_edge_flux_bulk()

SWMM_ENGINE_API int swmm_2d_get_edge_flux_bulk	(	SWMM_Engine	engine,
		double *	flux
	)

Bulk get normal edge flux at every edge of every triangle.

Output array must be pre-allocated to triangle_count * 3 doubles, indexed [tri*3 + localEdge]. Sign convention: positive flux flows outward through the edge's outward normal. Units m^2 s^-1 (depth- integrated normal speed). Combine with swmm_2d_edge_get_geometry_bulk to reconstruct cell-centred velocity (RT0): for each triangle, solve (NᵀN) v = Nᵀ q where rows of N are the outward unit normals and q[e] = flux[e] / length[e].

swmm_2d_get_head()

SWMM_ENGINE_API int swmm_2d_get_head	(	SWMM_Engine	engine,
		int	idx,
		double *	head
	)

Get total head at a triangle (z + depth).

swmm_2d_get_heads_bulk()

SWMM_ENGINE_API int swmm_2d_get_heads_bulk	(	SWMM_Engine	engine,
		double *	heads
	)

Bulk get heads for all triangles.

swmm_2d_get_max_depth()

SWMM_ENGINE_API int swmm_2d_get_max_depth	(	SWMM_Engine	engine,
		double *	max_depth
	)

Get the maximum depth across all triangles.

swmm_2d_get_net_source()

SWMM_ENGINE_API int swmm_2d_get_net_source	(	SWMM_Engine	engine,
		int	idx,
		double *	net_source
	)

Get net source/sink rate at a triangle (m/s).

swmm_2d_get_rainfall()

SWMM_ENGINE_API int swmm_2d_get_rainfall	(	SWMM_Engine	engine,
		int	idx,
		double *	rainfall
	)

Get rainfall intensity at a triangle (m/s).

swmm_2d_get_rel_tolerance()

SWMM_ENGINE_API int swmm_2d_get_rel_tolerance	(	SWMM_Engine	engine,
		double *	rtol
	)

Get CVODE relative tolerance.

swmm_2d_get_stat_max_depths()

SWMM_ENGINE_API int swmm_2d_get_stat_max_depths	(	SWMM_Engine	engine,
		double *	max_depths
	)

Get per-triangle max depth statistics (cumulative).

Parameters

max_depths

Output array (pre-allocated to triangle_count).

swmm_2d_get_total_exchange_flow()

SWMM_ENGINE_API int swmm_2d_get_total_exchange_flow	(	SWMM_Engine	engine,
		double *	flow
	)

Get total exchange flow rate (sum of all coupling flows, m³/s). Positive = net flow from 2D into 1D network.

swmm_2d_get_total_volume()

SWMM_ENGINE_API int swmm_2d_get_total_volume	(	SWMM_Engine	engine,
		double *	volume
	)

Get total 2D surface volume (sum of depth * area).

swmm_2d_is_active()

SWMM_ENGINE_API int swmm_2d_is_active	(	SWMM_Engine	engine,
		int *	active
	)

Check whether the 2D module is active for this simulation.

Parameters

engine	Engine handle.
active	Output: 1 if 2D is active, 0 otherwise.

Returns

SWMM_OK or error code.

Note

Valid after SWMM_STATE_INITIALIZED.

swmm_2d_set_abs_tolerance()

SWMM_ENGINE_API int swmm_2d_set_abs_tolerance	(	SWMM_Engine	engine,
		double	atol
	)

Set CVODE absolute tolerance.

swmm_2d_set_dry_depth()

SWMM_ENGINE_API int swmm_2d_set_dry_depth	(	SWMM_Engine	engine,
		double	dry_depth
	)

Set the dry depth threshold (m).

swmm_2d_set_edge_bc_head()

SWMM_ENGINE_API int swmm_2d_set_edge_bc_head	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double	head
	)

Set specified stage boundary head for an edge.

swmm_2d_set_edge_bc_slope()

SWMM_ENGINE_API int swmm_2d_set_edge_bc_slope	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		double	slope
	)

Set normal flow boundary slope for an edge.

swmm_2d_set_edge_bc_tseries_name()

SWMM_ENGINE_API int swmm_2d_set_edge_bc_tseries_name	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		const char *	name
	)

Set the timeseries NAME to drive a SPECIFIED_STAGE edge.

V-E2. Stores the name verbatim; the engine resolves it into a table index from SimulationContext::tables on the next forcing-step lookup (until then edge_bc_tseries[idx] is -2). Empty name clears the slot (back to constant edge_bc_head).

swmm_2d_set_edge_bc_type()

SWMM_ENGINE_API int swmm_2d_set_edge_bc_type	(	SWMM_Engine	engine,
		int	tri_idx,
		int	edge,
		int	bc_type
	)

Set boundary condition type for an edge.

swmm_2d_set_rel_tolerance()

SWMM_ENGINE_API int swmm_2d_set_rel_tolerance	(	SWMM_Engine	engine,
		double	rtol
	)

Set CVODE relative tolerance.

swmm_2d_set_vertex_z()

SWMM_ENGINE_API int swmm_2d_set_vertex_z	(	SWMM_Engine	engine,
		int	idx,
		double	z
	)

Set vertex Z (ground elevation).

Updates vz[idx] and recomputes the dependent geometry for every triangle incident to this vertex: tri_cz (centroid Z = mean of vertex Zs) and edge_mz (per-edge midpoint Z) so the solver's bed-elevation references stay consistent on the next step. XY-derived fields (tri_area, tri_cx, tri_cy, edge_length, edge_nx, edge_ny, edge_mx, edge_my) are unaffected.

When called while the engine is RUNNING, the solver state (head, depth) is intentionally not rewritten — head remains the value CVODE is integrating; the implied depth = head - bed therefore changes by the same amount as bed. This is the expected physical semantics ("raising the bed under water reduces water depth there").

Parameters

idx	Vertex index (0-based).
z	New ground elevation (project vertical units).

Here is the call graph for this function:

swmm_2d_triangle_count()

SWMM_ENGINE_API int swmm_2d_triangle_count	(	SWMM_Engine	engine,
		int *	count
	)

Get the number of mesh triangles.

swmm_2d_triangle_coupling_count()

SWMM_ENGINE_API int swmm_2d_triangle_coupling_count	(	SWMM_Engine	engine,
		int *	count
	)

Get the number of triangle-to-node coupling points.

swmm_2d_triangle_get_area()

SWMM_ENGINE_API int swmm_2d_triangle_get_area	(	SWMM_Engine	engine,
		int	idx,
		double *	area
	)

Get triangle area.

Parameters

idx	Triangle index.
area	Output area (m² or ft²).

swmm_2d_triangle_get_centroid()

SWMM_ENGINE_API int swmm_2d_triangle_get_centroid	(	SWMM_Engine	engine,
		int	idx,
		double *	cx,
		double *	cy,
		double *	cz
	)

Get triangle centroid coordinates.

swmm_2d_triangle_get_coupled_node()

SWMM_ENGINE_API int swmm_2d_triangle_get_coupled_node	(	SWMM_Engine	engine,
		int	tri_idx,
		int *	node_idx
	)

Get triangle coupling: which SWMM node is coupled to this triangle.

Parameters

tri_idx	Triangle index.
node_idx	Output: SWMM node index, or -1 if uncoupled.

swmm_2d_triangle_get_mannings()

SWMM_ENGINE_API int swmm_2d_triangle_get_mannings	(	SWMM_Engine	engine,
		int	idx,
		double *	n
	)

Get triangle Manning's roughness.

swmm_2d_triangle_get_neighbours()

SWMM_ENGINE_API int swmm_2d_triangle_get_neighbours	(	SWMM_Engine	engine,
		int	idx,
		int *	n0,
		int *	n1,
		int *	n2
	)

Get triangle neighbour indices (-1 = boundary edge).

Parameters

n0,n1,n2

Adjacent triangle indices across edges opposite v0,v1,v2.

swmm_2d_triangle_get_vertices()

SWMM_ENGINE_API int swmm_2d_triangle_get_vertices	(	SWMM_Engine	engine,
		int	idx,
		int *	v0,
		int *	v1,
		int *	v2
	)

Get triangle connectivity (3 vertex indices).

Parameters

idx	Triangle index (0-based).
v0,v1,v2	Output vertex indices.

swmm_2d_vertex_count()

SWMM_ENGINE_API int swmm_2d_vertex_count	(	SWMM_Engine	engine,
		int *	count
	)

Get the number of mesh vertices.

swmm_2d_vertex_coupling_count()

SWMM_ENGINE_API int swmm_2d_vertex_coupling_count	(	SWMM_Engine	engine,
		int *	count
	)

Get the number of vertex-to-node coupling points.

swmm_2d_vertex_get_coupled_node()

SWMM_ENGINE_API int swmm_2d_vertex_get_coupled_node	(	SWMM_Engine	engine,
		int	vertex_idx,
		int *	node_idx
	)

Get vertex coupling: which SWMM node is coupled to this vertex.

Parameters

vertex_idx	Vertex index.
node_idx	Output: SWMM node index, or -1 if uncoupled.

swmm_2d_vertex_get_head()

SWMM_ENGINE_API int swmm_2d_vertex_get_head	(	SWMM_Engine	engine,
		int	idx,
		double *	head
	)

Get reconstructed head at a vertex.

swmm_2d_vertex_get_heads_bulk()

SWMM_ENGINE_API int swmm_2d_vertex_get_heads_bulk	(	SWMM_Engine	engine,
		double *	heads
	)

Bulk get reconstructed heads at all vertices.

swmm_2d_vertex_get_xyz()

SWMM_ENGINE_API int swmm_2d_vertex_get_xyz	(	SWMM_Engine	engine,
		int	idx,
		double *	x,
		double *	y,
		double *	z
	)

Get vertex coordinates.

Parameters

idx	Vertex index (0-based).
x,y,z	Output coordinates.

swmm_2d_vertex_get_xyz_bulk()

SWMM_ENGINE_API int swmm_2d_vertex_get_xyz_bulk	(	SWMM_Engine	engine,
		double *	x,
		double *	y,
		double *	z
	)

Bulk get vertex coordinates.

Parameters

x,y,z

Output arrays (must be pre-allocated to vertex_count).