In this lecture, we'll cover the following:

• How to extract and identify the maximum vertical displacement and its location from an OpenSeesPy finite element model.
• How to organise and process nodal displacement data from an OpenSeesPy analysis.
• How to construct a function to visualise the displaced shape of an irregular mesh in 3D.
• How to interpolate displacement data onto a regular grid for plotting.
• How to apply masking to represent slab boundaries and openings accurately.
• How to define appropriate colour maps based on displacement behaviour.

We begin by extracting vertical displacements at each node and assembling them into a structured array. From this, we determine the maximum displacement by considering absolute values and use its index to recover the corresponding spatial location. This provides a quick quantitative check of the model response, which we then validate qualitatively by visualising the deflected shape.

We then develop a comprehensive plotting function to visualise the displaced shape of the slab. Because the mesh is irregular, we interpolate displacement data onto a regular grid before plotting. We carefully mask regions outside the slab boundary and within openings to ensure an accurate geometric representation. Finally, we enhance the visualisation using appropriate colour mapping that distinguishes between positive and negative deflections, and overlay additional features such as the undeformed mesh and column locations. This visual output serves as a benchmark for comparison with future custom finite element implementations.

Next up

In the next lecture, we will feed the same mesh into our custom Reissner–Mindlin finite element code and solve for nodal displacements.