> For the complete documentation index, see [llms.txt](https://alpaca4d.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alpaca4d.gitbook.io/docs/basics/loads.md).

# Loads

A **load** is an action on the structure. Loads are not applied directly: they are grouped into a [Load Pattern](/docs/basics/loads/load-pattern.md), which attaches a [time series](/docs/basics/time-history.md) saying how the group varies with time. The pattern is what goes into [Assemble](/docs/basics/assemble.md).

```
Load ──┐
Load ──┼──► Load Pattern ──► Assemble ──► Run Analysis
Load ──┘        ▲
                └── Time Series
```

## Components in this tab

| Component                                          | Nickname       | Applies                                       |
| -------------------------------------------------- | -------------- | --------------------------------------------- |
| [Gravity](/docs/basics/loads/gravity.md)           | `Gravity Load` | Self-weight of every element in the model.    |
| [Point](/docs/basics/loads/point-load.md)          | `Point Load`   | A concentrated force and moment at a point.   |
| [Beam](/docs/basics/loads/beam-load.md)            | `LinearLoad`   | A uniform line load along beam elements.      |
| [Shell](/docs/basics/loads/shell-load.md)          | `MeshLoad`     | A uniform surface pressure on shell elements. |
| [Mass Point](/docs/basics/loads/mass-point.md)     | `Mass Point`   | Added nodal mass, for dynamic analysis.       |
| [Load Pattern](/docs/basics/loads/load-pattern.md) | `Load Pattern` | Groups loads and gives them a time series.    |

## Notes that apply to all of them

* **Directions are global.** Force and moment vectors are in world coordinates, whatever the member orientation.
* **Loads find their target by position.** A point load is attached to the nearest node within the [Assemble](/docs/basics/assemble.md) **Tolerance**. If a load appears to do nothing, check that a node actually exists where you put it.
* [**Mass Point**](/docs/basics/loads/mass-point.md) **is not really a load.** It contributes mass, not force, and goes straight into Assemble's `LoadPatterns` input alongside the patterns — it does not need one of its own.