> ## 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.

# I ran into "Only cubic unit cells are currently supported" error.

## Issue:

Only cubic unit cells are currently supported.

![The Graph Unit Cell block with the Lattice Error: Only cubic unit cells are currently supported](https://files.learn.ntop.com/help-articles/lattices/32550563245459.png)

## Applies to:

* **Periodic Lattice**
* Hex prism diamond, Hex prism edge, Hex prism vertex centroid, Hex prism central axis edge, Hex prism laves phase, Tet oct vertex centroid, Oct vertex centroid

## Cause:

**Periodic Lattice** block only supports cubic unit cells.

## Solution:

Before we start, you need to enable *"Show deprecated blocks"* option from Settings > General ([What is a deprecated block?](/help-articles/knowledge-base/user-interface/what-is-a-deprecated-block)).

1. Add in the **Volume Lattice** \[Deprecated] block

2. Enter the following parameters

* Volume: Box (Unit Cell Box)
* Unit type: Graph Unit Cell
* Scale: same as the Box dimensions

![The deprecated volume lattice block generated from a box](https://files.learn.ntop.com/help-articles/lattices/32550563258515.png)

3. Add a **Graph from the Line Segments** block, dragging and dropping the ***line segments*** property chip from the **Volume Lattice** block.

![Using the line segments from the volume lattice block as an input for the Graph from Line Segments block](https://files.learn.ntop.com/help-articles/lattices/32550573278355.png)

4. Add a **Custom Unit Cell** block and use the Graph Lattice generated in the previous step as the first input and the Bounding Box from the **Volume Lattice** block as the Bounding Box input.

![Using the Graph from Line Segments block as the graph input to generate a Custom Unit Cell](https://files.learn.ntop.com/help-articles/lattices/32550573306643.png)

And that's it you can now successfully use the non-cubic unit cell in the **Periodic Lattice** block.

## Attachment:

* [Example File](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Lattices/non_cubic_unit_cell.ntop)

## Keywords:

*tet cell unit hex issue cubic prism*