8.2 Post-processing plugins

Post-processing plugins permit to extend the functionality of Gmsh's post-processing module. The difference between regular post-processing options (see section Post-processing options list) and post-processing plugins is that regular post-processing options only change the way the data is displayed, while post-processing plugins either create new post-processing views, or modify the data stored in a view (in a destructive, non-reversible way).

Plugins are available in the GUI by right-clicking on a view button (or by clicking on the black arrow next to the view button) and then selecting the `Plugin' submenu.

Here is the list of the plugins that are shipped by default with Gmsh:

Plugin(Annotate)

Plugin(Annotate) adds the text string `Text', in font `Font' and size `FontSize', in the view `iView'. If `ThreeD' is equal to 1, the plugin inserts the string in model coordinates at the position (`X',`Y',`Z'). If `ThreeD' is equal to 0, the plugin inserts the string in screen coordinates at the position (`X',`Y'). The string is aligned according to `Align'. If `iView' < 0, the plugin is run on the current view.

Plugin(Annotate) is executed in-place.

String options:

Text

Default value: "My Text"

Font

Default value: "Helvetica"

Align

Default value: "Left"

Numeric options:

X

Default value: 50

Y

Default value: 30

Z

Default value: 0

ThereD

Default value: 0

FontSize

Default value: 14

iView

Default value: -1

Plugin(Curl)

Plugin(Curl) computes the curl of the field in the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Curl) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(CutGrid)

Plugin(CutGrid) cuts the view `iView' with a rectangular grid defined by the 3 points (`X0',`Y0',`Z0') (origin), (`X1',`Y1',`Z1') (axis of U) and (`X2',`Y2',`Z2') (axis of V). The number of points along U and V is set with the options `nPointsU' and `nPointsV'. If `ConnectPoints' is zero, the plugin creates points; otherwise, the plugin generates quadrangles, lines or points depending on the values of `nPointsU' and `nPointsV'. If `iView' < 0, the plugin is run on the current view.

Plugin(CutGrid) creates one new view.

Numeric options:

X0

Default value: 0

Y0

Default value: 0

Z0

Default value: 0

X1

Default value: 1

Y1

Default value: 0

Z1

Default value: 0

X2

Default value: 0

Y2

Default value: 1

Z2

Default value: 0

nPointsU

Default value: 20

nPointsV

Default value: 20

ConnectPoints

Default value: 1

iView

Default value: -1

Plugin(CutMap)

Plugin(CutMap) extracts the isosurface of value `A' from the view `iView' and draws the `dTimeStep'-th value of the view `dView' on the isosurface. If `iView' < 0, the plugin is run on the current view. If `dTimeStep' < 0, the plugin uses, for each time step in `iView', the corresponding time step in `dView'. If `dView' < 0, the plugin uses `iView' as the value source. If `ExtractVolume' is nonzero, the plugin extracts the isovolume with values greater (if `ExtractVolume' > 0) or smaller (if `ExtractVolume' < 0) than the isosurface `A'.

Plugin(CutMap) creates as many views as there are time steps in `iView'.

Numeric options:

A

Default value: 0

dTimeStep

Default value: -1

dView

Default value: -1

ExtractVolume

Default value: 0

RecurLevel

Default value: 4

TargetError

Default value: 0

iView

Default value: -1

Plugin(CutParametric)

Plugin(CutParametric) cuts the view `iView' with the parametric function (`X'(u), `Y'(u), `Z'(u)), using `nPointsU' values of the parameter u in [`MinU', `MaxU']. If `ConnectPoints' is set, the plugin creates line elements; otherwise, the plugin generates points. If `iView' < 0, the plugin is run on the current view.

Plugin(CutParametric) creates one new view.

String options:

X

Default value: "0 + 1 * Cos(u)"

Y

Default value: "0 + 1 * Sin(u)"

Z

Default value: "0"

Numeric options:

MinU

Default value: 0

MaxU

Default value: 6.2832

nPointsU

Default value: 360

ConnectPoints

Default value: 0

iView

Default value: -1

Plugin(CutPlane)

Plugin(CutPlane) cuts the view `iView' with the plane `A'*X + `B'*Y + `C'*Z + `D' = 0. If `ExtractVolume' is nonzero, the plugin extracts the elements on one side of the plane (depending on the sign of `ExtractVolume'). If `iView' < 0, the plugin is run on the current view.

Plugin(CutPlane) creates one new view.

Numeric options:

A

Default value: 1

B

Default value: 0

C

Default value: 0

D

Default value: -0.01

ExtractVolume

Default value: 0

RecurLevel

Default value: 4

TargetError

Default value: 0

iView

Default value: -1

Plugin(CutSphere)

Plugin(CutSphere) cuts the view `iView' with the sphere (X-`Xc')^2 + (Y-`Yc')^2 + (Z-`Zc')^2 = `R'^2. If `ExtractVolume' is nonzero, the plugin extracts the elements inside (if `ExtractVolume' < 0) or outside (if `ExtractVolume' > 0) the sphere. If `iView' < 0, the plugin is run on the current view.

Plugin(CutSphere) creates one new view.

Numeric options:

Xc

Default value: 0

Yc

Default value: 0

Zc

Default value: 0

R

Default value: 0.25

ExtractVolume

Default value: 0

RecurLevel

Default value: 4

iView

Default value: -1

Plugin(Divergence)

Plugin(Divergence) computes the divergence of the field in the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Divergence) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(Eigenvalues)

Plugin(Eigenvalues) computes the three real eigenvalues of each tensor in the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Eigenvalues) creates three new scalar views.

Numeric options:

iView

Default value: -1

Plugin(Eigenvectors)

Plugin(Eigenvectors) computes the three (right) eigenvectors of each tensor in the view `iView' and sorts them according to the value of the associated eigenvalues. If `ScaleByEigenvalues' is set, each eigenvector is scaled by its associated eigenvalue. The plugin gives an error if the eigenvectors are complex. If `iView' < 0, the plugin is run on the current view.

Plugin(Eigenvectors) creates three new vector views.

Numeric options:

ScaleByEigenvalues

Default value: 1

iView

Default value: -1

Plugin(Evaluate)

Plugin(Evaluate) sets the `Component'-th component of the `TimeStep'-th time step in the view `iView' to the expression `Expression'. `Expression' can contain:

- the usual mathematical functions (Log, Sqrt, Sin, Cos, Fabs, ...) and operators (+, -, *, /, ^);

- the symbols x, y and z, to retrieve the coordinates of the current node;

- the symbols Time and TimeStep, to retrieve the current time and time step values;

- the symbol v, to retrieve the `Component'-th component of the field in `iView' at the `TimeStep'-th time step;

- the symbols v0, v1, v2, ..., v8, to retrieve each component of the field in `iView' at the `TimeStep'-th time step;

- the symbol w, to retrieve the `Component'-th component of the field in `ExternalView' at the `ExternalTimeStep'-th time step. If `ExternalView' and `iView' are based on different spatial grids, or if their data types are different, `ExternalView' is interpolated onto `iView';

- the symbols w0, w1, w2, ..., w8, to retrieve each component of the field in `ExternalView' at the `ExternalTimeStep'-th time step.

If `TimeStep' < 0, the plugin automatically loops over all the time steps in `iView' and evaluates `Expression' for each one. If `ExternalTimeStep' < 0, the plugin uses `TimeStep' instead. If `Component' < 0, the plugin automatically loops over all the components in the view and evaluates `Expression' for each one. If `iView' < 0, the plugin is run on the current view. If `ExternalView' < 0, the plugin uses `iView' instead.

Plugin(Evaluate) is executed in-place.

String options:

Expression

Default value: "v0*Sin(x)"

Numeric options:

Component

Default value: -1

TimeStep

Default value: -1

ExternalView

Default value: -1

ExternalTimeStep

Default value: -1

iView

Default value: -1

Plugin(Extract)

Plugin(Extract) extracts a combination of components from the `TimeStep'th time step in the view `iView'. If only `Expression0' is given (and `Expression1', ..., `Expression8' are all empty), the plugin creates a scalar view. If `Expression0', `Expression1' and/or `Expression2' are given (and `Expression3', ..., `Expression8' are all empty) the plugin creates a vector view. Otherwise the plugin creates a tensor view. In addition to the usual mathematical functions (Exp, Log, Sqrt, Sin, Cos, Fabs, etc.) and operators (+, -, *, /, ^), all expressions can contain the symbols v0, v1, v2, ..., vn, which represent the n components of the field, and the symbols x, y and z, which represent the three spatial coordinates. If `TimeStep' < 0, the plugin extracts data from all the time steps in the view. If `iView' < 0, the plugin is run on the current view.

Plugin(Extract) creates one new view.

String options:

Expression0

Default value: "Sqrt(v0^2+v1^2+v2^2)"

Expression1

Default value: ""

Expression2

Default value: ""

Expression3

Default value: ""

Expression4

Default value: ""

Expression5

Default value: ""

Expression6

Default value: ""

Expression7

Default value: ""

Expression8

Default value: ""

Numeric options:

TimeStep

Default value: -1

iView

Default value: -1

Plugin(ExtractElements)

Plugin(ExtractElements) extracts the elements from the view `iView' whose `TimeStep'-th values (averaged by element) are comprised between `MinVal' and `MaxVal'. If `iView' < 0, the plugin is run on the current view.

Plugin(ExtractElements) creates one new view.

Numeric options:

MinVal

Default value: 0

MaxVal

Default value: 1

TimeStep

Default value: 0

iView

Default value: -1

Plugin(FieldView)

Plugin(FieldView) evaluates a field on the choosen view.

Numeric options:

Component

Default value: -1

iView

Default value: -1

iField

Default value: -1

Plugin(FiniteElement)

Plugin(FiniteElement) solves simple PDEs using the finite element method. This is only intended as a demonstration tool: it is NOT intended for general use. Plugin(FiniteElement) creates a new view.

String options:

Equation

Default value: "Laplace"

BC1

Default value: "Dirichlet"

BC2

Default value: "Dirichlet"

Numeric options:

Parameter

Default value: 1

Volume

Default value: 1

Surface1

Default value: 2

Value1

Default value: 0

Surface2

Default value: 3

Value2

Default value: 1

Plugin(GSHHS)

Plugin(GSHHS) read different kind of contour lines data and write a .geo file on the surface of a sphere (the Earth). The principal application is to load GSHHS data (see http://www.soest.hawaii.edu/wessel/gshhs/gshhs.html). Valid values for "Format" are ): -"gshhs" : open GSHHS file -"loops2" : import 2D contour lines in simple text format : NB_POINTS_IN_FIRST_LOOP FIRST_LOOP_IS_CLOSED COORD1 COORD2 COORD1 COORD2 ... ... NB_POINTS_IN_SECOND_LOOP SECOND_LOOP_IS_CLOSED ... (LOOP_IS_CLOSED specify if this coast line describe a closed curve (0=no, 1=yes). In the case of "loops2" format, you can specify the the coordinate system used in the input file with the"Coordinate" option, valid values are -"lonlat" for longitude-latidute radian, -"lonlat_degrees" for longitude-latitude degrees, -"UTM" for universal transverse mercartor ("UTMZone" option should be specified) -"cartesian" for full 3D coordinates "radius" specify the earth radius. If the "iField" option is set, consecutive points closer than the value of the field iField (in meters) will not be added. If "MinStraitsFactor" >0 and if a field iField is provided, coastlines closer than MinStraitsFactor*field(IField) are merged and inner corners which form an angle < pi/3 are removed. The output is always in stereographic coordinates, if the "WritePolarSphere" option is not 0, a sphere is added to the geo file. WARNING : this plugin is still experimental and need polishing and error-handling. In particular, it will probably crash if an inexistant field id is given or if the input/output cannot be open. String options:

InFileName

Default value: "gshhs_c.b"

OutFileName

Default value: "earth.geo"

Format

Default value: "gshhs"

Coordinate

Default value: "cartesian"

Numeric options:

iField

Default value: -1

UTMZone

Default value: 0

UTMEquatorialRadius

Default value: 6.37814e+06

UTMPolarRadius

Default value: 6.35675e+06

radius

Default value: 6.37101e+06

WritePolarSphere

Default value: 1

MinStraitsFactor

Default value: 1

Plugin(Gradient)

Plugin(Gradient) computes the gradient of the field in the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Gradient) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(HarmonicToTime)

Plugin(HarmonicToTime) takes the values in the time steps `RealPart' and `ImaginaryPart' of the view `iView', and creates a new view containing (`iView'[`RealPart'] * cos(p) - `iView'[`ImaginaryPart'] * sin(p)), with p = 2*Pi*k/`nSteps', k = 0, ..., `nSteps'-1. If `iView' < 0, the plugin is run on the current view.

Plugin(HarmonicToTime) creates one new view.

Numeric options:

RealPart

Default value: 0

ImaginaryPart

Default value: 1

nSteps

Default value: 20

iView

Default value: -1

Plugin(Integrate)

Plugin(Integrate) integrates scalar fields over all the elements in the view `iView', as well as the circulation/flux of vector fields over line/surface elements. If `iView' < 0, the plugin is run on the current view.

Plugin(Integrate) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(Lambda2)

Plugin(Lambda2) computes the eigenvalues Lambda(1,2,3) of the tensor (S_ik S_kj + Om_ik Om_kj), where S_ij = 0.5 (ui,j + uj,i) and Om_ij = 0.5 (ui,j - uj,i) are respectively the symmetric and antisymmetric parts of the velocity gradient tensor. Vortices are well represented by regions where Lambda(2) is negative. If `iView' contains tensor elements, the plugin directly uses the tensors as the values of the velocity gradient tensor; if `iView' contains vector elements, the plugin uses them as the velocities from which to derive the velocity gradient tensor. If `iView' < 0, the plugin is run on the current view.

Plugin(Lambda2) creates one new view.

Numeric options:

Eigenvalue

Default value: 2

iView

Default value: -1

Plugin(LongitudeLatitude)

Plugin(LongituteLatitude) Project the view `iView' in Longitude-Latitude. If `iView' < 0, the plugin is run on the current view.

Plugin(LongituteLatitude) is executed in place.

Numeric options:

iView

Default value: -1

Plugin(MakeSimplex)

Plugin(MakeSimplex) decomposes all non- simplectic elements (quadrangles, prisms, hexahedra, pyramids) in the view `iView' into simplices (triangles, tetrahedra). If `iView' < 0, the plugin is run on the current view.

Plugin(MakeSimplex) is executed in-place.

Numeric options:

iView

Default value: -1

Plugin(ModulusPhase)

Plugin(ModulusPhase) interprets the time steps `realPart' and `imaginaryPart' in the view `iView' as the real and imaginary parts of a complex field and replaces them with their corresponding modulus and phase. If `iView' < 0, the plugin is run on the current view.

Plugin(ModulusPhase) is executed in-place.

Numeric options:

RealPart

Default value: 0

ImaginaryPart

Default value: 1

iView

Default value: -1

Plugin(Probe)

Plugin(Probe) gets the value of the view `iView' at the point (`X',`Y',`Z'). If `iView' < 0, the plugin is run on the current view.

Plugin(Probe) creates one new view.

Numeric options:

X

Default value: 0

Y

Default value: 0

Z

Default value: 0

iView

Default value: -1

Plugin(Remove)

Plugin(Remove) removes the marked items from the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Remove) is executed in-place.

Numeric options:

Text2D

Default value: 1

Text3D

Default value: 1

Points

Default value: 0

Lines

Default value: 0

Triangles

Default value: 0

Quadrangles

Default value: 0

Tetrahedra

Default value: 0

Hexahedra

Default value: 0

Prisms

Default value: 0

Pyramids

Default value: 0

Scalar

Default value: 1

Vector

Default value: 1

Tensor

Default value: 1

iView

Default value: -1

Plugin(Skin)

Plugin(Skin) extracts the skin (the boundary) of the view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Skin) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(Smooth)

Plugin(Smooth) averages the values at the nodes of the scalar view `iView'. If `iView' < 0, the plugin is run on the current view.

Plugin(Smooth) is executed in-place.

Numeric options:

iView

Default value: -1

Plugin(SphericalRaise)

Plugin(SphericalRaise) transforms the coordinates of the elements in the view `iView' using the values associated with the `TimeStep'-th time step. Instead of elevating the nodes along the X, Y and Z axes as in View[`iView'].RaiseX, View[`iView'].RaiseY and View[`iView'].RaiseZ, the raise is applied along the radius of a sphere centered at (`Xc', `Yc', `Zc'). To produce a standard radiation pattern, set `Offset' to minus the radius of the sphere the original data lives on. If `iView' < 0, the plugin is run on the current view.

Plugin(SphericalRaise) is executed in-place.

Numeric options:

Xc

Default value: 0

Yc

Default value: 0

Zc

Default value: 0

Raise

Default value: 1

Offset

Default value: 0

TimeStep

Default value: 0

iView

Default value: -1

Plugin(StreamLines)

Plugin(StreamLines) computes stream lines from the `TimeStep'-th time step of a vector view `iView' and optionally interpolates the scalar view `dView' on the resulting stream lines. The plugin takes as input a grid defined by the 3 points (`X0',`Y0',`Z0') (origin), (`X1',`Y1',`Z1') (axis of U) and (`X2',`Y2',`Z2') (axis of V). The number of points that are to be transported along U and V is set with the options `nPointsU' and `nPointsV'. The equation DX(t)/dt=V(x,y,z) is then solved with the initial condition X(t=0) chosen as the grid and with V(x,y,z) interpolated on the vector view. The time stepping scheme is a RK44 with step size `DT' and `MaxIter' maximum number of iterations. If `iView' < 0, the plugin is run on the current view. If `TimeStep' < 0, the plugin tries to compute streamlines of the unsteady flow.

Plugin(StreamLines) creates one new view. This view contains multi-step vector points if `dView' < 0, or single-step scalar lines if `dView' >= 0.

Numeric options:

X0

Default value: 0

Y0

Default value: 0

Z0

Default value: 0

X1

Default value: 1

Y1

Default value: 0

Z1

Default value: 0

X2

Default value: 0

Y2

Default value: 1

Z2

Default value: 0

nPointsU

Default value: 10

nPointsV

Default value: 1

MaxIter

Default value: 100

DT

Default value: 0.1

TimeStep

Default value: 0

dView

Default value: -1

iView

Default value: -1

Plugin(Transform)

Plugin(Transform) transforms the homogeneous node coordinates (x,y,z,1) of the elements in the view `iView' by the matrix [`A11' `A12' `A13' `Tx'] [`A21' `A22' `A23' `Ty'] [`A31' `A32' `A33' `Tz']. If `SwapOrientation' is set, the orientation of the elements is reversed. If `iView' < 0, the plugin is run on the current view.

Plugin(Transform) is executed in-place.

Numeric options:

A11

Default value: 1

A12

Default value: 0

A13

Default value: 0

A21

Default value: 0

A22

Default value: 1

A23

Default value: 0

A31

Default value: 0

A32

Default value: 0

A33

Default value: 1

Tx

Default value: 0

Ty

Default value: 0

Tz

Default value: 0

SwapOrientation

Default value: 0

iView

Default value: -1

Plugin(Triangulate)

Plugin(Triangulate) triangulates the points in the view `iView', assuming that all the points belong to a surface that can be projected one-to-one onto a plane. If `iView' < 0, the plugin is run on the current view.

Plugin(Triangulate) creates one new view.

Numeric options:

iView

Default value: -1

Plugin(Warp)

Plugin(Warp) transforms the elements in the view `iView' by adding to their node coordinates the vector field stored in the `TimeStep'-th time step of the view `dView', scaled by `Factor'. If `dView' < 0, the vector field is taken as the field of surface normals multiplied by the `TimeStep' value in `iView'. (The smoothing of the surface normals is controlled by the `SmoothingAngle' parameter.) If `iView' < 0, the plugin is run on the current view.

Plugin(Warp) is executed in-place.

Numeric options:

Factor

Default value: 1

TimeStep

Default value: 0

SmoothingAngle

Default value: 180

dView

Default value: -1

iView

Default value: -1