[Updated 7/6/2011 - More 2D & sound resources]
At the recent Game2Learn event in Dundee, I spoke about ways of reducing the costs of developing new learning games and/or virtual worlds. One of the key ways to reduce costs is to use free stuff – of which there is a lot out there. Many of these resources are also useful for students learning game development.
Before using any resource be sure to check the license and conditions for use – some resources allow reuse for any purpose, others are only for non-commercial use.
If you are developing your own game or using Unity, then chances are that you can import models that are available in the popular Collada format (and with mesh import this should also come to Second Life/OpenSim before too long).
Google’s 3D Warehouse is home to thousands of static 3D models – particularly strong on models of notable buildings, due to the links between Google Sketchup, the 3D warehouse and Google Earth, but interiors, objects and vehicles can all be found.
An interesting new resource (especially if you want military type models, or models of things you might find in or around army bases) is the ADL 3D Repository. You’ll also find a lot of regular household items (chandeliers and bidets!) alongside the weaponry and vehicles, plus models of US soldiers and Afghan civilians.
More commercially oriented sites like TurboSquid are marketplaces for the buying and selling of 3D models – prices vary dramatically but there is a lot of low cost and free content to be found, and the quality is sometimes of a very professional standard.
2D Textures and Images
You can search Flickr for Creative Commons licensed photos, but the photos are not normally very good for use as textures. Wikimedia Commons is another good source of photos, but few are ideal for use as textures.
In comparison, CGTextures specialises in textures that can be used in game development – and has thousands on offer. Free for commercial or non-commercial use. The only use that is explicitly not allowed is in creating your own texture packs (e.g. you can use some of these textures to build something in Second Life that you will sell commercially, but you are not allowed to create an in-world texture pack to sell or give away)
HasGraphics links to a small but quite high-quality range of sprites, tilesets and other 2D graphics resources, while Moosader has posted a range of her own creations under public-domain license at OpenArt.
Keith Ditchburn has collected more links for 2D textures and 3D models over at Toymaker. You can also always do a search for images licensed for reuse at Flick or on Google.
Music and Sound Effects
Freesound is home to a huge number of Creative Commons licensed sound effects, while ccMixter homes similarly licensed music samples, loops and mixes. Also check the Free Music Archive and the Creative Commons audio blog.
Back at OpenArt, Moosader has collected (and produced some of) a small range of retro-styled music files suitable for games.
OpenSim and Second Life Specific
There are two OpenSim specific archive formats – OAR and IAR. OAR files archive complete regions – including terrain and all objects including textures, scripts, sounds and more. IAR files archive users’ inventory – again including all data required to fully restore the items (scripts, sounds, etc.).
A third archive option (for which I’ve been unable to find a specific name) is the xml format used when backing up objects from Second Life or OpenSim using the export option in Imprudence and other 3rd party client software. (See discussion e.g. here). While most online discussion of this format is based on how to transfer your own objects, it also provides another way to share OpenSim/Second Life objects.
Four sources for OpenSim Archives (OAR files, Hypergrid Business)
OpenSim Creations (OAR files, IAR files, XML objects, terrains files, textures. Includes many NSFW)
OpenSim Terrains – Flickr Set
OSAvatars – Avatar textures, parts and clothing