nglib.h File Reference

Library interface to the netgen meshing kernel. More...

Go to the source code of this file.

Classes
class	Ng_Meshing_Parameters
	Netgen Meshing Parameters class. More...
Defines
#define	DLL_HEADER
#define	NG_VOLUME_ELEMENT_MAXPOINTS   10
#define	NG_SURFACE_ELEMENT_MAXPOINTS   8
#define	DLL_HEADER
#define	NG_VOLUME_ELEMENT_MAXPOINTS   10
	Maximum allowed number of nodes per volume element.
#define	NG_SURFACE_ELEMENT_MAXPOINTS   8
	Maximum allowed number of nodes per surface element.
Typedefs
typedef void *	Ng_Mesh
	Data type for NETGEN mesh.
typedef void *	Ng_CSG_Geometry
	Data type for NETGEN CSG geometry.
typedef void *	Ng_Geometry_2D
	Data type for NETGEN 2D geometry.
typedef void *	Ng_STL_Geometry
	Data type for NETGEN STL geometry.
Enumerations
enum	Ng_Surface_Element_Type {   NG_TRIG = 1, NG_QUAD = 2, NG_TRIG6 = 3, NG_QUAD6 = 4,   NG_QUAD8 = 5 }
	Currently implemented surface element types. More...
enum	Ng_Volume_Element_Type { NG_TET = 1, NG_PYRAMID = 2, NG_PRISM = 3, NG_TET10 = 4 }
	Currently implemented volume element types. More...
enum	Ng_Result {   NG_ERROR = -1, NG_OK = 0, NG_SURFACE_INPUT_ERROR = 1, NG_VOLUME_FAILURE = 2,   NG_STL_INPUT_ERROR = 3, NG_SURFACE_FAILURE = 4, NG_FILE_NOT_FOUND = 5 }
	Values returned by Netgen functions. More...
Functions
DLL_HEADER void	Ng_Init ()
	Initialise the Netgen library and prepare for use.
DLL_HEADER void	Ng_Exit ()
	Exit the Netgen meshing kernel in a clean manner.
DLL_HEADER Ng_Mesh *	Ng_NewMesh ()
	Create a new (and empty) Netgen Mesh Structure.
DLL_HEADER void	Ng_DeleteMesh (Ng_Mesh *mesh)
	Delete an existing Netgen Mesh Structure.
DLL_HEADER void	Ng_SaveMesh (Ng_Mesh *mesh, const char *filename)
	Save a Netgen Mesh to disk.
DLL_HEADER Ng_Mesh *	Ng_LoadMesh (const char *filename)
	Load a Netgen VOL Mesh from disk into memory.
DLL_HEADER Ng_Mesh *	Ng_SetProperties (Ng_Mesh *m, int surfnr, int bcnr, int domin, int domout)
	Set element options.
DLL_HEADER Ng_Result	Ng_MergeMesh (Ng_Mesh *mesh, const char *filename)
	Merge a Netgen VOL Mesh from disk into an existing mesh in memory.
DLL_HEADER Ng_Result	Ng_MergeMesh (Ng_Mesh *mesh1, Ng_Mesh *mesh2)
	Merge one Netgen Mesh into another Netgen Mesh in the case when both are already in memory.
DLL_HEADER void	Ng_AddPoint (Ng_Mesh *mesh, double *x)
	Add a point to a given Netgen Mesh Structure.
DLL_HEADER void	Ng_AddSurfaceElement (Ng_Mesh *mesh, Ng_Surface_Element_Type et, int *pi)
	Add a surface element to a given Netgen Mesh Structure.
DLL_HEADER void	Ng_AddVolumeElement (Ng_Mesh *mesh, Ng_Volume_Element_Type et, int *pi)
	Add a volume element to a given Netgen Mesh Structure.
DLL_HEADER void	Ng_RestrictMeshSizeGlobal (Ng_Mesh *mesh, double h)
	Apply a global restriction on mesh element size.
DLL_HEADER void	Ng_RestrictMeshSizePoint (Ng_Mesh *mesh, double *p, double h)
	Locally restrict the mesh element size at the given point.
DLL_HEADER void	Ng_RestrictMeshSizeBox (Ng_Mesh *mesh, double *pmin, double *pmax, double h)
	Locally restrict the mesh element size within a specified box.
DLL_HEADER Ng_Result	Ng_GenerateVolumeMesh (Ng_Mesh *mesh, Ng_Meshing_Parameters *mp)
	Create a 3D Volume Mesh given a Surface Mesh.
DLL_HEADER int	Ng_GetNP (Ng_Mesh *mesh)
	Returns the Number of Points present in the specified Mesh.
DLL_HEADER int	Ng_GetNSE (Ng_Mesh *mesh)
	Returns the Number of Surface Elements present in the specified Mesh.
DLL_HEADER int	Ng_GetNE (Ng_Mesh *mesh)
	Returns the Number of Volume Elements present in the specified Mesh.
DLL_HEADER void	Ng_GetPoint (Ng_Mesh *mesh, int num, double *x)
DLL_HEADER Ng_Surface_Element_Type	Ng_GetSurfaceElement (Ng_Mesh *mesh, int num, int *pi)
DLL_HEADER Ng_Volume_Element_Type	Ng_GetVolumeElement (Ng_Mesh *mesh, int num, int *pi)
DLL_HEADER void	Ng_AddPoint_2D (Ng_Mesh *mesh, double *x)
DLL_HEADER void	Ng_AddBoundarySeg_2D (Ng_Mesh *mesh, int pi1, int pi2)
DLL_HEADER int	Ng_GetNP_2D (Ng_Mesh *mesh)
DLL_HEADER int	Ng_GetNE_2D (Ng_Mesh *mesh)
DLL_HEADER int	Ng_GetNSeg_2D (Ng_Mesh *mesh)
DLL_HEADER void	Ng_GetPoint_2D (Ng_Mesh *mesh, int num, double *x)
DLL_HEADER Ng_Surface_Element_Type	Ng_GetElement_2D (Ng_Mesh *mesh, int num, int *pi, int *matnum=NULL)
DLL_HEADER void	Ng_GetSegment_2D (Ng_Mesh *mesh, int num, int *pi, int *matnum=NULL)
DLL_HEADER Ng_Geometry_2D *	Ng_LoadGeometry_2D (const char *filename)
DLL_HEADER Ng_Result	Ng_GenerateMesh_2D (Ng_Geometry_2D *geom, Ng_Mesh **mesh, Ng_Meshing_Parameters *mp)
DLL_HEADER void	Ng_HP_Refinement (Ng_Geometry_2D *geom, Ng_Mesh *mesh, int levels)
DLL_HEADER Ng_STL_Geometry *	Ng_STL_LoadGeometry (const char *filename, int binary=0)
DLL_HEADER Ng_STL_Geometry *	Ng_STL_NewGeometry ()
DLL_HEADER void	Ng_STL_AddTriangle (Ng_STL_Geometry *geom, double *p1, double *p2, double *p3, double *nv=NULL)
DLL_HEADER void	Ng_STL_AddEdge (Ng_STL_Geometry *geom, double *p1, double *p2)
DLL_HEADER Ng_Result	Ng_STL_InitSTLGeometry (Ng_STL_Geometry *geom)
DLL_HEADER Ng_Result	Ng_STL_MakeEdges (Ng_STL_Geometry *geom, Ng_Mesh *mesh, Ng_Meshing_Parameters *mp)
DLL_HEADER Ng_Result	Ng_STL_GenerateSurfaceMesh (Ng_STL_Geometry *geom, Ng_Mesh *mesh, Ng_Meshing_Parameters *mp)
DLL_HEADER void	Ng_Uniform_Refinement (Ng_Mesh *mesh)
DLL_HEADER void	Ng_2D_Uniform_Refinement (Ng_Geometry_2D *geom, Ng_Mesh *mesh)
DLL_HEADER void	Ng_STL_Uniform_Refinement (Ng_STL_Geometry *geom, Ng_Mesh *mesh)
DLL_HEADER void	Ng_CSG_Uniform_Refinement (Ng_CSG_Geometry *geom, Ng_Mesh *mesh)
DLL_HEADER void	Ng_Generate_SecondOrder (Ng_Mesh *mesh)
DLL_HEADER void	Ng_2D_Generate_SecondOrder (Ng_Geometry_2D *geom, Ng_Mesh *mesh)
DLL_HEADER void	Ng_STL_Generate_SecondOrder (Ng_STL_Geometry *geom, Ng_Mesh *mesh)
DLL_HEADER void	Ng_CSG_Generate_SecondOrder (Ng_CSG_Geometry *geom, Ng_Mesh *mesh)

---

Detailed Description

Library interface to the netgen meshing kernel.

Author:

Joachim Schoeberl

Date:

7. May 2000

This header file provides access to the core functionality of the Netgen Mesher via a library interface, without an interactive User Interface.

The intention of providing these set of functions is to allow system developers to integrate Netgen into top-level code, to act as the low level mesh generation / optimisation kernel.

---

Define Documentation

#define DLL_HEADER

#define DLL_HEADER

#define NG_SURFACE_ELEMENT_MAXPOINTS   8

Maximum allowed number of nodes per surface element.

#define NG_SURFACE_ELEMENT_MAXPOINTS   8

#define NG_VOLUME_ELEMENT_MAXPOINTS   10

#define NG_VOLUME_ELEMENT_MAXPOINTS   10

Maximum allowed number of nodes per volume element.

---

Typedef Documentation

typedef void* Ng_CSG_Geometry

Data type for NETGEN CSG geometry.

typedef void* Ng_Geometry_2D

Data type for NETGEN 2D geometry.

typedef void* Ng_Mesh

Data type for NETGEN mesh.

typedef void* Ng_STL_Geometry

Data type for NETGEN STL geometry.

---

Enumeration Type Documentation

enum Ng_Result

Values returned by Netgen functions.

Enumerator:

NG_ERROR
NG_OK
NG_SURFACE_INPUT_ERROR
NG_VOLUME_FAILURE
NG_STL_INPUT_ERROR
NG_SURFACE_FAILURE
NG_FILE_NOT_FOUND

enum Ng_Surface_Element_Type

Currently implemented surface element types.

Enumerator:

NG_TRIG
NG_QUAD
NG_TRIG6
NG_QUAD6
NG_QUAD8

enum Ng_Volume_Element_Type

Currently implemented volume element types.

Enumerator:

NG_TET
NG_PYRAMID
NG_PRISM
NG_TET10

---

Function Documentation

DLL_HEADER void Ng_2D_Generate_SecondOrder	(	Ng_Geometry_2D *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER void Ng_2D_Uniform_Refinement	(	Ng_Geometry_2D *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER void Ng_AddBoundarySeg_2D	(	Ng_Mesh *	mesh,
		int	pi1,
		int	pi2
	)

DLL_HEADER void Ng_AddPoint	(	Ng_Mesh *	mesh,
		double *	x
	)

Add a point to a given Netgen Mesh Structure.

This function allows points to be directly added to a Netgen mesh structure by providing the co-ordinates.

Each call to the function allows only one point to be added.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
x	Pointer to an array of type double containing the co-ordinates of the point to be added in the form: x[0] = X co-ordinate x[1] = Y co-ordinate x[2] = Z co-ordinate

DLL_HEADER void Ng_AddPoint_2D	(	Ng_Mesh *	mesh,
		double *	x
	)

DLL_HEADER void Ng_AddSurfaceElement	(	Ng_Mesh *	mesh,
		Ng_Surface_Element_Type	et,
		int *	pi
	)

Add a surface element to a given Netgen Mesh Structure.

This function allows the top-level code to directly add individual Surface Elements to a Netgen Mesh Structure by providing the type of element to be added and the indices of the points which constitute the element.

Note:

• The points referred to by the surface elements must have been added prior to calling this function.
• Currently only triangular elements are supported, and the Surface Element Type argument is not used.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
et	Surface Element type provided via the enumerated type Ng_Surface_Element_Type
pi	Pointer to an array of integers containing the indices of the points which constitute the surface element being added

DLL_HEADER void Ng_AddVolumeElement	(	Ng_Mesh *	mesh,
		Ng_Volume_Element_Type	et,
		int *	pi
	)

Add a volume element to a given Netgen Mesh Structure.

This function allows the top-level code to directly add individual Volume Elements to a Netgen Mesh Structure by providing the type of element to be added and the indices of the points which constitute the element.

Note:

• The points referred to by the volume elements must have been added prior to calling this function.
• Currently only tetrahedral elements are supported, and the Volume Element Type argument is not used.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
et	Volume Element type provided via the enumerated type Ng_Volume_Element_Type
pi	Pointer to an array of integers containing the indices of the points which constitute the volume element being added

DLL_HEADER void Ng_CSG_Generate_SecondOrder	(	Ng_CSG_Geometry *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER void Ng_CSG_Uniform_Refinement	(	Ng_CSG_Geometry *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER void Ng_DeleteMesh

(

Ng_Mesh *

mesh

)

Delete an existing Netgen Mesh Structure.

Use this function to delete an existing Netgen mesh structure and release the used memory.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh

DLL_HEADER void Ng_Exit

(

)

Exit the Netgen meshing kernel in a clean manner.

Use this function to exit the meshing sub-system in a clean and orderly manner.

DLL_HEADER void Ng_Generate_SecondOrder

(

Ng_Mesh *

mesh

)

DLL_HEADER Ng_Result Ng_GenerateMesh_2D	(	Ng_Geometry_2D *	geom,
		Ng_Mesh **	mesh,
		Ng_Meshing_Parameters *	mp
	)

DLL_HEADER Ng_Result Ng_GenerateVolumeMesh	(	Ng_Mesh *	mesh,
		Ng_Meshing_Parameters *	mp
	)

Create a 3D Volume Mesh given a Surface Mesh.

After creating a surface mesh, this function can be utilised to automatically generate the corresponding 3D Volume Mesh.

Mesh generation parameters (such as grading, maximum element size, etc.) are specified via the meshing parameters class which also needs to be passed to this function.

Note: Currently, Netgen generates pure tetrahedral volume meshes.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
mp	Pointer to a copy of the Meshing Parameters class (Ng_Meshing_Parameters), filled up with the required values

Returns:

Ng_Result Status of the Mesh Generation routine. More details regarding the return value can be found in the description of Ng_Result

DLL_HEADER Ng_Surface_Element_Type Ng_GetElement_2D	(	Ng_Mesh *	mesh,
		int	num,
		int *	pi,
		int *	matnum = NULL
	)

DLL_HEADER int Ng_GetNE

(

Ng_Mesh *

mesh

)

Returns the Number of Volume Elements present in the specified Mesh.

Given an already existent Netgen Mesh Structure, this function returns the number of volume elements currently present within the Mesh.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh

Returns:

Integer Data-type with the number of volume elements in the Mesh

DLL_HEADER int Ng_GetNE_2D

(

Ng_Mesh *

mesh

)

DLL_HEADER int Ng_GetNP

(

Ng_Mesh *

mesh

)

Returns the Number of Points present in the specified Mesh.

Given an already existent Netgen Mesh Structure, this function returns the number of points currently present within the Mesh.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh

Returns:

Integer Data-type with the number of points in the Mesh

DLL_HEADER int Ng_GetNP_2D

(

Ng_Mesh *

mesh

)

DLL_HEADER int Ng_GetNSE

(

Ng_Mesh *

mesh

)

Returns the Number of Surface Elements present in the specified Mesh.

Given an already existent Netgen Mesh Structure, this function returns the number of surface elements currently present within the Mesh.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh

Returns:

Integer Data-type with the number of surface elements in the Mesh

DLL_HEADER int Ng_GetNSeg_2D

(

Ng_Mesh *

mesh

)

DLL_HEADER void Ng_GetPoint	(	Ng_Mesh *	mesh,
		int	num,
		double *	x
	)

DLL_HEADER void Ng_GetPoint_2D	(	Ng_Mesh *	mesh,
		int	num,
		double *	x
	)

DLL_HEADER void Ng_GetSegment_2D	(	Ng_Mesh *	mesh,
		int	num,
		int *	pi,
		int *	matnum = NULL
	)

DLL_HEADER Ng_Surface_Element_Type Ng_GetSurfaceElement	(	Ng_Mesh *	mesh,
		int	num,
		int *	pi
	)

DLL_HEADER Ng_Volume_Element_Type Ng_GetVolumeElement	(	Ng_Mesh *	mesh,
		int	num,
		int *	pi
	)

DLL_HEADER void Ng_HP_Refinement	(	Ng_Geometry_2D *	geom,
		Ng_Mesh *	mesh,
		int	levels
	)

DLL_HEADER void Ng_Init

(

)

Initialise the Netgen library and prepare for use.

This function needs to be called by the third-party program before beginning to use the other Netgen specific functions.

DLL_HEADER Ng_Geometry_2D* Ng_LoadGeometry_2D

(

const char *

filename

)

DLL_HEADER Ng_Mesh* Ng_LoadMesh

(

const char *

filename

)

Load a Netgen VOL Mesh from disk into memory.

A Netgen mesh saved in the internal VOL format can be loaded into a Netgen Mesh structure using this function.

Parameters:

filename

Pointer to a character array containing the name of the file to load

Returns:

Ng_Mesh Pointer to a Netgen Mesh type Ng_Mesh containing the mesh loaded from disk

DLL_HEADER Ng_Result Ng_MergeMesh	(	Ng_Mesh *	mesh,
		const char *	filename
	)

Merge a Netgen VOL Mesh from disk into an existing mesh in memory.

A Netgen mesh saved in the internal VOL format can be merged into an existing Netgen Mesh structure using this function.

Parameters:

mesh	Name of the Mesh structure already existent in memory
filename	Pointer to a character array containing the name of the file to load

Returns:

Ng_Result Status of the merge operation

DLL_HEADER Ng_Result Ng_MergeMesh	(	Ng_Mesh *	mesh1,
		Ng_Mesh *	mesh2
	)

Merge one Netgen Mesh into another Netgen Mesh in the case when both are already in memory.

(NOTE: First version implemented, Sakalli)

This function can be used to merge two Netgen meshes already present in memory.

Parameters:

mesh1	Parent Mesh structure into which the second mesh will be merged
mesh2	Child mesh structure which will get merged into the parent mesh

Returns:

Ng_Result Status of the merge operation

DLL_HEADER Ng_Mesh* Ng_NewMesh

(

)

Create a new (and empty) Netgen Mesh Structure.

This function creates a new Netgen Mesh, initialises it, and returns a pointer to the created mesh structure.

Use the returned pointer for subsequent operations which involve mesh operations.

Returns:

Ng_Mesh Pointer to a Netgen Mesh type Ng_Mesh

DLL_HEADER void Ng_RestrictMeshSizeBox	(	Ng_Mesh *	mesh,
		double *	pmin,
		double *	pmax,
		double	h
	)

Locally restrict the mesh element size within a specified box.

Similar to the function Ng_RestrictMeshSizePoint, this function allows the size of elements within a mesh to be locally limited.

However, rather than limit the mesh size at a single point, this utility restricts the local mesh size within a 3D Box region, specified via the co-ordinates of the two diagonally opposite points of a cuboid.

Note: This function only limits the Maximum size of the elements within the specified region.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
pmin	Pointer to an Array of type double, containing the three co-ordinates of the first point of the cuboid: pmin[0] = X co-ordinate pmin[1] = Y co-ordinate pmin[2] = Z co-ordinate
pmax	Pointer to an Array of type double, containing the three co-ordinates of the opposite point of the cuboid: pmax[0] = X co-ordinate pmax[1] = Y co-ordinate pmax[2] = Z co-ordinate
h	Variable of type double, specifying the maximum allowable mesh size at that point

DLL_HEADER void Ng_RestrictMeshSizeGlobal	(	Ng_Mesh *	mesh,
		double	h
	)

Apply a global restriction on mesh element size.

This utility allows the user to apply a global mesh element size limitation.

During mesh creation, in the absence of an explicit local size restriction around the neighbourhood of a point within the meshing domain, this global size restriction will be utilised.

Note: This function only limits the Maximum size of an element within the mesh.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
h	Variable of type double, specifying the maximum allowable mesh size

DLL_HEADER void Ng_RestrictMeshSizePoint	(	Ng_Mesh *	mesh,
		double *	p,
		double	h
	)

Locally restrict the mesh element size at the given point.

Unlike the function Ng_RestrictMeshSizeGlobal, this function allows the user to locally restrict the maximum allowable mesh size at a given point.

The point is specified via its three cartesian co-ordinates.

Note: This function only limits the Maximum size of the elements around the specified point.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
p	Pointer to an Array of type double, containing the three co-ordinates of the point in the form: p[0] = X co-ordinate p[1] = Y co-ordinate p[2] = Z co-ordinate
h	Variable of type double, specifying the maximum allowable mesh size at that point

DLL_HEADER void Ng_SaveMesh	(	Ng_Mesh *	mesh,
		const char *	filename
	)

Save a Netgen Mesh to disk.

This function allows a generated mesh structure to be saved to disk.

A Mesh saved using this function, will be written to disk in the Netgen VOL file format.

Parameters:

mesh	Pointer to an existing Netgen Mesh structure of type Ng_Mesh
filename	Pointer to a character array containing the name of the file to which the mesh should be saved

DLL_HEADER Ng_Mesh* Ng_SetProperties	(	Ng_Mesh *	m,
		int	surfnr,
		int	bcnr,
		int	domin,
		int	domout
	)

Set element options.

Changes the element options of a Netgen mesh in VOL format . (Sakalli)

Parameters:

mesh	Name of the Mesh structure already existent in memory
surfnr	Set surface number
bcnr	Set boundary number
domin	Set domain in
domout	Set domain out

Returns:

Ng_Result Status of the boundary operation

DLL_HEADER void Ng_STL_AddEdge	(	Ng_STL_Geometry *	geom,
		double *	p1,
		double *	p2
	)

DLL_HEADER void Ng_STL_AddTriangle	(	Ng_STL_Geometry *	geom,
		double *	p1,
		double *	p2,
		double *	p3,
		double *	nv = NULL
	)

DLL_HEADER void Ng_STL_Generate_SecondOrder	(	Ng_STL_Geometry *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER Ng_Result Ng_STL_GenerateSurfaceMesh	(	Ng_STL_Geometry *	geom,
		Ng_Mesh *	mesh,
		Ng_Meshing_Parameters *	mp
	)

DLL_HEADER Ng_Result Ng_STL_InitSTLGeometry

(

Ng_STL_Geometry *

geom

)

DLL_HEADER Ng_STL_Geometry* Ng_STL_LoadGeometry	(	const char *	filename,
		int	binary = 0
	)

DLL_HEADER Ng_Result Ng_STL_MakeEdges	(	Ng_STL_Geometry *	geom,
		Ng_Mesh *	mesh,
		Ng_Meshing_Parameters *	mp
	)

DLL_HEADER Ng_STL_Geometry* Ng_STL_NewGeometry

(

)

DLL_HEADER void Ng_STL_Uniform_Refinement	(	Ng_STL_Geometry *	geom,
		Ng_Mesh *	mesh
	)

DLL_HEADER void Ng_Uniform_Refinement

(

Ng_Mesh *

mesh

)