Graphical User Interface

Reminder: GUI = Graphical User Interface.

General description

Accessing the option is done through the menu Tools->Options (or shift + ctrl + N). This menu is decomposed into numerous categories:

  • General
  • Geometry
  • Mesh
  • Solver
  • Post-Pro
  • Plus eventually the post processing views: View [0], View [1], …

In GMSH, a View corresponds to a function visualized on a mesh.

Camera

Operation Result
left click Rotation
right click Translation
wheel Zoom

Please use the bottom buttons X, Y and Z to reset the camera along an axis. The 1:1 button reset the scale (zoom).

Camera

Options General

They are divided into different tabs.

General (yes, again)

The options that can be usefull for this tutorial are:

  • Use dark interface: better for our eyes (at least, mine)
  • Show bounding box: draw corners (and coordinates) of the bounding box of the geometry
To save your favorite options for next launch: File->Save options as default.

Axes

You can here delete the small axis displayed on bottom right. This is particularly usefull when doing screen shot or saving nice figures.

Color

It’s here possible to move the light source (on top right). This lighting effect can also be deleted in the tab of each View.

Options Geometry

The most usefull option in the tab Visibility is to display normal and tangeant vectors of surfaces, and the checkbox to display (or not) surfaces and volumes.

Options Mesh

Again, the Visibility tab propose to display:

  • 1D element (segment) which are not displayed by default. This can be sometimes confusing when reading a 1D mesh.
  • The face of the element to make then opaque
  • Normal and Tangent vectors (bottom)
Displaying normal vectors

View options (Post-Processing)

Even if GMSH can do vizualisation and post processing, Paraview is designed for that and is way more powerful.
For this menu to be visible, a finite element function must be opened, coming from example from GetDP or FreeFem++.

The View[0] categorie contains different tabs:

  • General
  • Axes
  • Visibility
  • Transfo
  • Aspect
  • Color
  • Map

It’s possible to save the option associated to particular View using File->Save Model Option. A .opt file is then created and the next time GMSH open the post-processing file, the chosen options are again loaded (camera position, …).

General

(Most) Interesting are:

  • Interval type: Never chose “numeric values”, otherwise GMSH will probably crash due to too many number to display. isovalues or filled isovalues are really interesting for visualisation.
  • Range mode:
    • Per Time Step
    • Custom
    • Step : In GMSH, Step are time step, but also real part (Step 0) and imaginary part (Step 1)

Axes

You can try it.

Visibility

  • Draw element outlines is used to superimposed (or not) the mesh onto the View
  • Time Display: for complex time-independent function, select Harmonic Data to display “real part” and “imaginary part” in the title of View (instead of Step)

Transfo

This is where the View (not the function!) can be transformed:

  • Translation, Rotation, … according to the matrix (rotation) and vector (translation)
  • Normal Raise: plot a 2D solution in 3D (example below)
Normal Raise example

Color

You can here desactivate the lighting effect with Enable lighting.

Color Map

Some pre-defined colormaps are available by typing 0,1,2,3…,9.

Some plugins

These plugins are accessible in Tools->Plugins menu. They can modify the data and make some simple operations on them.

Plugins obviously do not modify the content of the file, only the View

ModulusPhase

Compute the modulus and the phase of a View. The View is here override.

It can be launched with the default parameter as long as the View to work on is selected (-1= current View).

ModifyComponents

Compute a mathematical operation on the component (if vector data or tensor data) of the View.

Delete a View from memory, reload it, …

  • A View can be set to visible or not using the checkbox close to its name
  • Deleting a View from the memory: click on the arrow on the right of the name of the view. Then in the dropdown menu select Remove. Every View can be removed at once, too.
  • Reloading a View can be done by typing r or in its dropdown menu by selecting Reload.

Image exportation (png, jpg, …)

In the menu, select Files->Export and then chose the desired output format, or type the full name of the output file and GMSH will guess its format from the extension you provide (png, jpg, …).