> For the complete documentation index, see [llms.txt](https://manual.karamba3d.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://manual.karamba3d.com/beta/2-getting-started/2-getting-started-1/setting-up-a-structural-analysis/2.2.1-define-the-model-elements.md).

# 2.2.1 Define the Model Elements

In Karamba3D, straight lines form the basis for beam, truss, and spring elements, while shells and slabs are based on meshes. Figure 2.2.1.1 illustrates a definition that creates a single beam, assembles a model, and displays it. The **“Create Linear Element”** component, in its LineToBeam variant, takes a **“Line”** object as input and generates a beam element from it. By default, Karamba3D assumes all geometry input is in meters, disregarding the unit settings chosen in Rhino.

Assigning names to elements is beneficial when working with large, complex structures. In Figure 2.2.1.1, the name “MyBeam” is assigned to the new beam element. For grouping elements, it can be useful to give them multiple names at once. This can be achieved by separating the alternative names with "|" which stands for "or".

{% hint style="info" %}
Element identifiers do not need to be unique, allowing for the grouping of elements.
{% endhint %}

<figure><img src="/files/XHdisR3Skk84Av1tMsTE" alt=""><figcaption><p>Fig. 2.2.1.1: A structural model with geometry only</p></figcaption></figure>

The **“Assemble”** component consolidates all structural information into a model. When connected to a panel, the model displays its basic features: **“c.Length”** represents the characteristic length, calculated as the diagonal of the bounding box of the structure. For a beam, two nodes define one element. In the absence of material definitions, Karamba3D automatically generates a default material, applied to the default beam and shell cross-section, resulting in two cross-sections as shown in Figure 2.2.1.1. The model does not contain loads but includes a default load-case.

{% hint style="info" %}
A load-case represents a scenario where a group of external actions simultaneously impact a model. For instance, wind can affect a structure from multiple directions, but not all directions at once. Each distinct wind direction is treated as a separate load-case.
{% endhint %}


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