+++
title = "Structure"
weight = 60
+++

## Particle structures

BornAgain supports two- and three-dimensional particle arrangements through
dedicated structure classes.

### 2D structures

Particles deposited on a surface or suspended from an interface. Use
`Dilute2D` or `Dense2D` for disordered assemblies, and structures like
`Crystal1D`, `Crystal2D`, `FiniteCrystal2D`, or `RadialParacrystal` for
ordered or partially ordered systems.

Add these structures to a layer with `deposit2D`, `addDeposit2D`, `suspend2D`,
or `addSuspend2D`.

See [2D structures](2d/) for details on interference functions and
size-distribution models.

### 3D structures

Particles distributed throughout a layer's volume, such as nanoparticles in a
polymer film. Use `Dilute3D` for uncorrelated volume distributions and add
them with `fill3D` or `add3D`.

See [3D structures](3d/) for details on correlation models.

### History

3D structures were introduced in BornAgain 24.
