Genesis3D

What is it?: An open-source (seperate license) 3D engine dating back to 1998.
What computer will it run on?: It needs Windows with DirectX 6 or higher.
Similar products: Crystal Space.

Genesis3D is a real-time 3D rendering environment for all of your real-time 3D needs. With a large online community, free online forums, and many links to Genesis3D developers…you will find all the support and tools that you need to begin developing world-class, real-time 3D applications today.

This is probably the best-known and best supported of the commercial open source game engines. The licensing policy is quite interesting: Basically, the engine is free. You can use it for any kind of project, free or commercial, as long as you do not change the code. If you change the code of the engine, you have to release all your code changes as well. If you want to change the code of the engine, and not release your own code, then you have to pay ($10,000 per project).

However, Genesis3D is far from being a tool for the beginner. It does not come with a scripting language, you have to program your game by yourself, preferably with Visual C++. Which is not free either, neither is 3D Studio Max, which you might need to design your characters.

Reality Factory

Genesis3D is an engine, not a development tool. Without a programming environment (usually Visual C++), nothing goes. For those who want to utilize the engine but are not programmers, Reality Factory was created.

Reality Factory is a set of Open Source Tools for creating games and other high-performance multimedia applications.

It includes support for two-dimensional (2-D) and three-dimensional (3-D) graphics, sound and music,input, advanced character animation, advanced world editing & animation capabilities, and many features commonly found in first and third person action games (such as customizable weapons, ammo, health and damage, customizable menu's). Reality Factory also has many cutting edge special effects, such as dynamic colored lighting, advanced particle effects (rain, sprays (useful for richochets and blood-type effects) and other similar effects).

Reality Factory also comes complete with a full NPC system, an extensive environment and player audio effects (customizeable sounds for taking damage, falling, and dying, custom environment audio effects for walking on snow, rock, concrete, metal whatever you build YOUR reality out of ;)

Links

Genesis 3D Homepage
Project Z might help you learn to use it.
ProjectZ began as an attempt on my part to learn the GENESIS engine, during it's creation, ProjectZ has been open source and hopefully beneficial to everyone involved. This latest revision has been completely rewritten from the previous version and includes such items as static objects and dema zombies along with collision detection and warp portals. The layout of the new version is structured to be tutorialistic, wow, is that even a word? Anyhow, it is meant to be a tutorial of getting GENESIS initiated and a demo created.
Reality Factory Homepage
RealityFactory FAQ
Resources