# 2.2.6 Provide Cross Sections

There are two methods for attaching cross sections to elements:

1. **Direct Assignment:** Directly at the component where the element is created, as shown in Fig. 2.2.6.1.
2. **Assignment via Names or Regular Expressions:** Using element names (“B” and “S” in Fig. 2.2.6.2) or regular expressions by plugging cross sections into the **“Assemble”** component.

<figure><img src="https://2671626451-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F6rkhS8IteqWJRfUuJlL5%2Fuploads%2FghnaJ6CyoM3JOzlf0CyI%2FProvideCrossSections.png?alt=media&#x26;token=68cc9223-f4a5-452f-a99c-db06fb91a53a" alt=""><figcaption><p>Fig. 2.2.6.1: Definition of a cross section.</p></figcaption></figure>

Figure 2.2.6.1 illustrates how to attach a custom cross section to an element. The example shows an I-profile with a height and width of 50 cm. The physical unit of any input or output value is indicated in the help text that appears when hovering over the corresponding plug.

{% hint style="info" %}
Assignment via the **“Assemble”**-component overrides direct assignment at the element.
{% endhint %}

![ Fig. 2.2.6.2: Definition of a cross section via element names.](https://2671626451-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MCkDlhlZpqUmakSqOrp%2Fsync%2F3f61559fc4219559cfaed2f7bde0172b4bec68e2.png?generation=1595316043948089\&alt=media)

Figure 2.2.6.2 shows how cross sections can be attached to elements via their names **“Elem|Id”**:

1. Definition of a beam cross section.
2. Definition of a shell cross section.
3. Selection of a cross section from the default cross section library.

An element's index can be used as its default name.

Arbitrary I-, hollow box, filled trapezoid, and hollow circular cross sections can be defined for beams. Alternatively, Karamba3D allows users to select a predefined standard cross section. For shells, it is possible to attach a different cross section to each element.

Karamba3D cross sections are available as multi-components and can be accessed via the single **“Cross Sections”** component. The drop-down menu allows for the selection of the cross section type.

{% hint style="info" %}
Should you not assign a cross section to your beam or shell elements, the [default cross section ](https://manual.karamba3d.com/2-getting-started/karamba3d-entities#default-settings)will be used.
{% endhint %}