> ## 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.

# Domains

A Domain requires two key components, material properties and a body or mesh to apply them to. The body input will be an Implicit Body, Lattice, FE Point, or FE Mesh, depending on the Domain type. The material properties are usually defined inside an Attribute block, with a few exceptions for the **Lattice Domain** and the **Parametric Domain** blocks.

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There are 4 main types of Domains for running simulations, Fluid, Solid (Implicit Body), Solid (FE Mesh/Point), and Lattice. There are two **Solid Domain** blocks because they are used to run different analyses. We recommend adding the **Domain List** to you workflow first, as nTop will automatically provide the correct **Solid Domain** based on the parent **Domain List** block. The gif below demonstrates how to add a **Solid Domain** for both a **FE Domain List** and a **Virtual Domain List**. If you don't see **Virtual Domain List** as an option, you may need to change the **Simulation Model** block overload as shown below.

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The table below shows the Domain options for running a **Field Optimization**, if you would like to learn more about these Domains we recommend reviewing our [Parametric FE Domains](https://learn.ntop.com/courses/440-field-optimization/lessons/parametric-fe-domains/) lesson.

| **Parametric Domain**          | **Visual Representation**                | **Design Parameters**                    | **Field Optimizable Design Parameters**                      |
| ------------------------------ | ---------------------------------------- | ---------------------------------------- | ------------------------------------------------------------ |
| Parametric Lattice Domain      | A Parametric Lattice Domain example      | Unit Cell, Boundary Behaviour, Cell Size | - Min and Max Thickness                                      |
| Parametric Shell Domain        | A Parametric Shell Domain example        |                                          | - Min and Max Shell Thickness                                |
| Parametric Shell-Infill Domain | A Parametric Shell-Infill Domain example | Unit Cell, Cell Size                     | - Min and Max Infill Thickness - Min and Max Shell Thickness |
| Parametric Voronoi Domain      | A Parametric Voronoi Domain example      |                                          | - Min and Max Cell Size - Min and Max Thickness              |