> For the complete documentation index, see [llms.txt](https://amazing-assets.gitbook.io/terrain-to-obj/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://amazing-assets.gitbook.io/terrain-to-obj/run-time-api.md).

# Run-time API

**Terrain To OBJ** extension methods can be brought into scope with this using directive:

```
using AmazingAssets.TerrainToOBJ;
```

Unity [TerrainData](https://docs.unity3d.com/Documentation/ScriptReference/TerrainData.html) class now will have two additional methods **ToOBJ** and **ToOBJStreamWriter**:

### ToOBJ

```csharp
string ToOBJ (int vertexCountHorizontal, int vertexCountVertical, 
              Normal normalReconstruction, Vector3 originPosition)
```

Converts [TerrainData](https://docs.unity3d.com/ScriptReference/TerrainData.html) object into **OBJ** mesh and returns result as a **string**. 

{% hint style="warning" %}
Depending on the number of vertex counts used, the **string** size can reach hundreds of megabytes or even gigabytes. Be careful. 
{% endhint %}

```csharp
string ToOBJ (int vertexCountHorizontal, int vertexCountVertical, 
              int chunkCountHorizontal, int chunkCountVertical, 
              bool perChunkUV, Normal normalReconstruction, Vector3 originPosition)
```

Splits generated terrain mesh into multi-chunk 2D grid and return result a **string**.

If *<mark style="color:blue;">perChunkUV</mark>* property is enabled, each mesh inside 2D grid array has normalized UVs in the range of \[0, 1].&#x20;

<div><figure><img src="/files/GS6rHIu1W2m8RR5SHdUB" alt=""><figcaption><p>Per chunk UV - <strong>False</strong></p></figcaption></figure> <figure><img src="/files/ExO5HyrnDlTTqVqXKqjO" alt=""><figcaption><p>Per chunk UV - <strong>True</strong></p></figcaption></figure></div>

```csharp
string ToOBJ (int vertexCountHorizontal, int vertexCountVertical, 
              int chunkCountHorizontal, int chunkCountVertical, 
              int positionX, int positionY, 
              bool perChunkUV, Normal normalReconstruction, Vector3 originPosition)
```

Splits generated terrain mesh into multi-chunk 2D grid and exports one mesh with index of *<mark style="color:blue;">positionX</mark>* and *<mark style="color:blue;">positionY</mark>*.

### ToOBJStreamWriter

```csharp
void ToOBJStreamWriter (System.IO.StreamWriter streamWriter, 
                        int vertexCountHorizontal, int vertexCountVertical, 
                        Normal normalReconstruction, Vector3 originPosition)
```

[TerrainData](https://docs.unity3d.com/ScriptReference/TerrainData.html) is converted into OBJ file as a single mesh and using *<mark style="color:blue;">streamWriter</mark>* is instantly saved into a file.

```csharp
void ToOBJStreamWriter (System.IO.StreamWriter streamWriter, 
                        int vertexCountHorizontal, int vertexCountVertical, 
                        int chunkCountHorizontal, int chunkCountVertical, 
                        bool perChunkUV, Normal normalReconstruction, Vector3 originPosition)
```

Splits generated terrain mesh into multi-chunk 2D grid and using *<mark style="color:blue;">streamWriter</mark>* is instantly\
saved into a file.

```csharp
void ToOBJStreamWriter (System.IO.StreamWriter streamWriter, 
                        int vertexCountHorizontal, int vertexCountVertical, 
                        int chunkCountHorizontal, int chunkCountVertical, 
                        int positionX, int positionY, 
                        bool perChunkUV, Normal normalReconstruction, Vector3 originPosition)
```

Splits generated terrain mesh into multi-chunk 2D grid, but only mesh with index of *<mark style="color:blue;">positionX</mark>* and *<mark style="color:blue;">positionY</mark>* is exported and using *<mark style="color:blue;">streamWriter</mark>* is instantly saved into a file.


---

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