> ## 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.

# Graph Unit Cells

You can use the **Graph Unit Cell** block to create a Periodic Lattice. A Unit Cell Preview will pop up when selecting your Unit Cell type, and you can change the parameters in the view settings from the Display tab on the Right Panel. You can toggle between *Implicit* and *Graph* display modes. With Implicit display mode, you can change the Thickness of the Unit Cell to view a 3D rendering. You can also toggle the Bounding Box view to show the extent of the Unit Cell.

<Frame>
  <img src="https://files.learn.ntop.com/lessons/graph-unit-cells/unit_cell_hud.gif" />
</Frame>

The second input of the **Graph Unit Cell** block allows you to change the cell's orientation, or you can use the**Orient Unit Cell** block. The orientation changes the layout of the Unit Cell, which can affect the structure based on its usage.

<Frame>
  <img src="https://files.learn.ntop.com/lessons/graph-unit-cells/orient_unit_cell.gif" />
</Frame>

<Note>
  **Note**: The preview will show thickness, but no thickness will be added to the Unit Cell at this step. The View Setting is just for visualization purposes.
</Note>

## Graph Properties

In the Properties of graph-based lattices, you can find the *graph* property. To use this property, drag it from the Properties panel into the Notebook or a block input. Expand the *graph* property to see *valencies*, *edge counts*, and more properties.

<Frame>
  <img src="https://files.learn.ntop.com/lessons/graph-unit-cells/210_5_3-graph-properties-1.gif" />
</Frame>

## Graph Unit Cell Options

Below are the options available for Graph Unit Cells. If you are receiving an error when using a Hex prism and other non-cubic unit cells, Follow the steps listed in this [article](https://support.ntop.com/hc/en-us/articles/32550573343891).

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

## Some Notes on our Lattice Types:

* **Honeycombs**are hard to beat in the stiffness-to-weight ratio in their extruded direction. Still, they are much softer in the other two orthogonal directions (by around an order of magnitude).
* **Octet**lattices are stiff in all three principal directions but more challenging to manufacture.
* **Stochastic foams** are much more compliant but the easiest to finely tailor to a design's functional requirements through cell size and relative density.
* **Auxetic honeycombs**can be designed to exhibit special properties like a negative Poisson's ratio (contracts inwards when compressed instead of barreling outwards).

For more information on our lattices and their properties, check out this blog post, [Architected Materials for Impact Absorption](https://www.ntop.com/resources/blog/architected-materials-impact-absorption/).