Ogre is a very extensible engine, and we have an active community who have produced many add-on projects which are not officially supported by the core team, but have proven extremely helpful to users and have provoked much discussion and collaboration in the forums. Many people have asked for a quick reference to the add-ons and how to get hold of them, so here it is!

Supported add-ons

To promote collaboration and to make them easy to locate, the modules supported by the current Ogre release are located in the OGRECave group:

Project Name	Description
ogre-audiovideo	Ogre3D plugins for OpenAL audio and theora video playback
particleuniverse	particle engine developed in C++, which can be used as a plugin
ogre-caelum	plugin for rendering of dynamic and realistic skies
ogre-pagedgeometry	plugin for rendering of dense vegetation
ogre-procedural	procedural geometry for Ogre3D
ogre-gpgpu	GPGPU compute with Ogre using CUDA or OpenCL
ogre-planet	dynamic level of detail for planetary rendering
shiny	a shader and material management library for OGRE
meshmagick	A command-line tool for manipulating meshes, e.g. merging & changing formats

Legacy add-ons

Over the lifetime of OGRE many more add-ons were created which are no longer maintained nowadays.
However often they can be updated with very little effort to work again with Ogre1 and thus be useful to you.

Most of them still live in the sourceforge SVN:

https://sourceforge.net/projects/ogreaddons/

Some of them were updated for ogre 1.10+ and are now available on Bitbucket:

https://bitbucket.org/ogreaddons/

Note before updating one of the legacy addons here, check if any of the supported addons above already cover your needs. However if you do update one of the addons, please open an issue on the Ogre github repository so we can include the updated code in OGRECave.

below is the full list of the legacy-add-ons

Project Name	Current / Last Maintainer(s)	Description
BetaGUI	betajaen	Small and lightweight GUI system using only overlays
blenderimport	haffax	Import OGRE .mesh files into Blender
cal3d2ogre	lordlorik	Converter from Cal3d data formats to Ogre
ceguimeshviewer	pablobuiras	In-engine mesh viewer using CEGui
clipmapterrain	hellcatv, shirsoft	Geometry clipmaps implementation for terrain
cubicfractalterrain	antiarc	An example of how to generate terrain using cubic splines and fractal detail refinement
dbmArchive	jaysprenkle	An Archive plugin which reads and writes standard Unix DBM files
displacementmapterrain	dwhittaker	A terrain demo which uses vertex programs to displace the terrain into it's final shape, allowing large terrains in smaller data sizes
forests	john_j	A library for rendering expansive forests using Ogre
gilesexporter	walaber	An exporter for Gile[s], a global illumination system.
GOOF	falagard	Game Object Oriented Framework
HDRlib	lui85	A library to make it easier to incorporate HDR effects into your software using OGRE
mayaextras	omekinteractive	A set of additional Maya tools including a dotscene exporter and node animation curve exporter
mdl2mesh	borundin	A LUA script to convert Neverwinter Nights .mdl files into OGRE's .mesh format.
meshviewer	cthno1	A Windows-based GUI tool for viewing and tweaking Ogre meshes and materials.
multiscenemanager	metax	An experiment to see if multiple scene managers could be used simultanteously to render different parts of a single scene
nogredex	gfmrose	A binding to the NVIDIA PhysX Engine (fomerly Novodex)
oasis	godot_found	A framework to tie together multiple game engine systems into a more integrated whole
ogrefsrad	psyclonist	Tool to allow Fluid Studios' radiosity processor fsrad to be used with Ogre meshes
ogreopcode	_mental_	Demonstration Opcode (collision detection) bindings for Ogre meshes.
overlayeditor	patrick_kooman	Windows tool for graphical editing of Ogre .overlay files
paginglandscape	jamilan, nfz, kuranes	Plugin SceneManager(s) for handling large-scale, paging terrain
particleeditor	mac, spannerman	CEGui-based graphical particle system editor
posertools	kaynine	Exporter for Poser
QtOgreFramework	esuvs, kardoon	Integration framework for using Ogre with Qt
rmogreexporter	none	Export OGRE-compatible material scripts and shaders direct from RenderMonkey
sketchupexporter	Kojack	Export meshes from Google Sketchup
simplepagedterrain	HexiDave	An infinitely repeating paging terrain system
truespaceexporter	thecomputerguru	Exporter for Calgari Truespace
uOgreBrowser	ryandeboer	Binding to uBrowser to allow you to render web pages onto geometry in Ogre.
worldminion	sinbad	Convert a polygon soup into a structured cell/portal graph.
wxOgreMVC	sinbad	MVC framework for Ogre based tools using wxWidgets