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 for list-based datasets or creates a new view for other datasets.

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: "Projection"

Parameter

Default value: "Sin(x*y)"

Gamma1BC

Default value: ""

Gamma2BC

Default value: ""

Numeric options:

Omega

Default value: 1

Gamma1

Default value: 0

Gamma1Value

Default value: 0

Gamma2

Default value: 0

Gamma2Value

Default value: 0

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(HomologyComputation)

Plugin(HomologyComputation) computes generators for (relative) homology groups and their thick cuts.

Plugin(HomologyComputation) creates new views.

String options:

Filename

Default value: "homology.msh"

Numeric options:

PhysicalGroupForDomain1

Default value: 0

PhysicalGroupForDomain2

Default value: 0

PhysicalGroupForSubdomain1

Default value: 0

PhysicalGroupForSubdomain2

Default value: 0

ComputeGenerators

Default value: 1

ComputeThickCuts

Default value: 0

OmitDimensions

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