In Version 6 of Game Maker 3D functionality was added. It is not meant for big 3D games, it is more an element to make your game a bit more fancy. There are certain limitations for 3d games.
- 3D in Game Maker is limited to the graphics part. There are no builtin functions for 3d collision, raycasting or quaternions.
- Certain things can't be used when in 3d mode:
- Backgrounds [Unsure about if you cant use backgrounds] you can use backrounds as textures for objects
- Mouse position, however you can write a script to translate it into either a 3d position or a direction (for mouselook)
- Collision checking is limited to 2d with builtin functions, however you can write your own 3D collition checking script.
- To use 3D, you must be fluent in GML. There are libraries for 3D functions, but these have limitations as well.
- Requires GameMaker: Professional Edition
- You must be familiar with 3D coding. A lot of things are very difficult to understand if you haven't done any 3D before.
- Getting a reasonable speed is not easy. This isn't optimized for speed.