# Add-Ons


An add-on is an extension that can be presented as any engine addition: plugin, library, material, asset pack, etc.


Add-ons can be downloaded from Add-On Store at [https://store.unigine.com/](https://store.unigine.com/). Add-On Store contains add-ons created by UNIGINE and add-ons created and uploaded by users. Depending on the add-on usage conditions, add-ons can be downloaded free of charge or upon payment. For more details, see the [Add-On Store documentation](https://store.unigine.com/documentation).


> **Notice:** If the add-on has been upgraded, its newer version should be downloaded and added to the UNIGINE project manually.


## Articles in This Section

- [Airport Assets](../../sdk/addons/airport/index.md)

- [Eastern European Countryside](../../sdk/addons/eastern_european_countryside/index.md)

- [Docs Sample Content](../../sdk/addons/content/index.md)

- [IG Aviation](../../sdk/addons/aircraft/index.md)

- [Industrial Assets](../../sdk/addons/industrial/index.md)

- [Road Tool Constructor](../../sdk/addons/road/index.md)

- [Scans](../../sdk/addons/scans/index.md)

- [Vegetation](../../sdk/addons/vegetation/index.md)

- [VFX](../../sdk/addons/vfx/index.md)

- [VideoTexture](../../sdk/addons/videotexture/index.md)

- [Weather](../../sdk/addons/weather/index.md)

- [Georeferenced Terrain Generation](../../sdk/addons/terrain_geo/index.md)

- [Procedural Generation Assets](../../sdk/addons/procedural_generation_assets/index.md)