In this lecture, we'll cover the following:

• Writing a function to visualise a 2D finite element mesh.
• Extracting and organising mesh data (nodes, coordinates, elements, corners).
• Plotting quadrilateral elements while filtering out points and lines.
• Adding optional features: node display, element display, and labelling.
• Handling mesh data issues (e.g. reshaping coordinate arrays).
• Demonstrating the effect of mesh density and subdivision.

In this lecture, we build a custom function to visualise a 2D finite element mesh with flexible display options. We extract key data from the mesh structure, including node tags, coordinates, and element connectivity, and create a utility mapping between node tags and indices. We then focus on plotting only quadrilateral elements, ensuring they are displayed correctly by closing their geometry, and introduce optional features such as showing or hiding nodes, elements, and their respective labels.

We also address a practical issue with data formatting, correcting the structure of the nodal coordinate array to enable proper plotting. Beyond basic visualisation, we enhance the function by adding element-centred labels, boundary outlines, and node annotations with offsets for clarity. Finally, we explore how mesh density affects the visual output and preview upcoming extensions to the meshing process, including handling openings and enforcing specific node locations, as well as ensuring correct element node ordering for compatibility with the finite element solver.

Next up

In the next lecture, we will address an important practical issue: ensuring that element node ordering is consistent and compatible with our finite element solver.