> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Unit Cells

A **Unit Cell** is the smallest portion of a lattice that defines the three-dimensional pattern to be repeated. There are three Unit Cell types in nTop: Non-Parametric Unit Cells, 1 Parameter Unit Cells, and 2 Parameter Unit Cells. The number indicates how many parameters are needed to define the Unit Cell. Below you can see the three Unit Cell types and descriptions:

<Frame>
  <img src="https://files.learn.ntop.com/lessons/unit-cells/210_4_1-unit-cells-.png" />
</Frame>

The standard Unit Cell options are located in the *Lattices* tab.

<Frame>
  <img src="https://files.learn.ntop.com/lessons/unit-cells/210_4_2-unit-cell-dropdown.png" />
</Frame>