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# Beginner's Guide

Like any Python script, you should start by importing the core modules from the EasyFEA package:

```{eval-rst}
.. jupyter-execute::

    from EasyFEA import Display, ElemType, Models, Simulations
    from EasyFEA.Geoms import Domain
```

----

The most commonly used modules in EasyFEA are:

```{eval-rst}
.. autosummary::
    ~EasyFEA.utilities.Display 
    ~EasyFEA.fem.ElemType 
    ~EasyFEA.Models
    ~EasyFEA.Simulations
    ~EasyFEA.Geoms
```

Let's now create a 2D {py:class}`~EasyFEA.fem.Mesh` using a simple rectangular domain:

```{eval-rst}
.. jupyter-execute::

    # ----------------------------------------------
    # Mesh
    # ----------------------------------------------
    L = 120  # mm
    h = 13

    domain = Domain((0, 0), (L, h), h / 3)
    mesh = domain.Mesh_2D([], ElemType.QUAD9, isOrganised=True)
    Display.Plot_Mesh(mesh)
```
    
----

Next, define a linear {py:class}`~EasyFEA.Models.Elastic.Isotropic` material and set up the {py:class}`~EasyFEA.Simulations.Elastic`  simulation:

```{eval-rst}
.. jupyter-execute::

    # ----------------------------------------------
    # Simulation
    # ----------------------------------------------
    E = 210000  # MPa
    v = 0.3
    F = -800  # N

    mat = Models.Elastic.Isotropic(2, E, v, planeStress=True, thickness=h)

    simu = Simulations.Elastic(mesh, mat)
```
    
----

Once the simulation has been set up, defining the boundary conditions, solving the problem and visualizing the results is straightforward.

```{eval-rst}
.. jupyter-execute::
    
    nodesX0 = mesh.Nodes_Conditions(lambda x, y, z: x == 0)
    nodesXL = mesh.Nodes_Conditions(lambda x, y, z: x == L)

    simu.add_dirichlet(nodesX0, [0, 0], ["x", "y"])
    simu.add_surfLoad(nodesXL, [F / h / h], ["y"])

    simu.Solve()

    # ----------------------------------------------
    # Results
    # ----------------------------------------------
    Display.Plot_Mesh(simu, deformFactor=10)
    Display.Plot_BoundaryConditions(simu)
    Display.Plot_Result(simu, "uy", plotMesh=True)
    Display.Plot_Result(simu, "Svm", plotMesh=True, ncolors=11)
```
    
----

This script is available in the {doc}`HelloWorld example <examples/HelloWorld>`.

For additional details, please refer to either the {doc}`EasyFEA API documentation <api/index>` or the comprehensive collection of {doc}`examples <examples/index>`.