> ## 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.

# How to create CFD Boundaries

## Objective:

Learn how to use the block **CFD Boundary on FE Mesh** to create named boundaries and export them with your FE Mesh. Setting up CFD boundary zones allows you to modify the underlying geometry in nTop without having to manually update the boundary conditions in the CFD application, thereby enabling automated design workflows.

## Applies to:

* Ansys Fluent
* nTop 3.4+

## Procedure:

**1.** Start with an [FE Volume Mesh](/help-articles/knowledge-base/meshing-workflows/how-to-create-an-fe-volume-mesh) of your design.

**2.** Choose boundaries

* * Decide what boundaries you need to define for your analysis. Use either [**FE Boundary by Body**](/help-articles/knowledge-base/structures/how-to-select-boundaries-using-boundary-by-body) or [**FE Boundary by Floodfill**](/help-articles/knowledge-base/structures/how-to-select-boundaries-of-an-fe-mesh-fe-boundary-by-flood-fill) to choose the areas on your mesh.
    * Make sure to use the **Faces** as the entity in your selection, since the CFD Boundaries can only be applied to volumetric elements

**3.** Create CFD Boundaries

* * Add a **CFD Boundary on FE Mesh** block (make sure to have [beta blocks](/help-articles/knowledge-base/user-interface/what-are-beta-blocks) turned on)
    * Insert one of the boundary selection blocks into the FE set field
    * Choose the most accurate CFD Boundary type for your selection
* ![A list of the available Type options for the CFD Boundary on FE Mesh block](https://files.learn.ntop.com/help-articles/structures/4402792384147.png)
  * Repeat this process for each selection

![An image showing how to use FE Boundary by Body blocks to select portions of a mesh at inlets and outlets. The Inlet and Outlet boundaries are then used for the CFD Boundary on FE Mesh blocks to specify the boundary type.](https://files.learn.ntop.com/help-articles/structures/4402792384787.png)

**4.** Export Mesh and Boundaries together

* * Add in the beta block, **Export FE Mesh to CFD** to allow the FE sets to be exported with your mesh. To use this block, your FE Mesh needs to be an **FE Volume** mesh and not an **FE Surface** mesh.
    * Insert the **FE Volume Mesh**
    * Add the block **CFD Boundary List** into the Boundaries input. Insert your boundaries into the List
    * Choose a path and save your file as a .msh

![Using the Export FE Mesh to CFD block to export the CFD boundaries that were just created at the defined inlet and outlet](https://files.learn.ntop.com/help-articles/structures/4402792580115.png)

And that's it! You've successfully created and exported CFD boundaries.

Are you still having issues? Contact the [support team](https://support.ntopology.com/hc/en-us/requests/new), and we'll be happy to help!

## Download the Example file:

* [Example file](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Simulation/CFD%20Boundary%20Example.ntop)

## Keywords:

*analysis mesh boundary design fe fluid set beta fluent cfd how-to zone outlet inlet*