Just so you know I am not good with remembering these things. This is probably a dumb question. 3D graphics are made how?
If you're talking about 3D models, then there are various programs you can use to create them. Blender is one that is free, and the paid ones I know about are 3DS Max, Cinema 4D, and Maya. If that's not what you mean, then I apologise! lol, I don't actually have any experience creating 3D games yet, that's something I want to work on later, or when I get an idea for a good 3D game, so I'm not sure how to get the 3D models from this software into the game engine yet! (although I have seen that there are open source things such as SIO2, which is a 3D game engine I believe, which I'm guessing is one way to do it?!) Hope that's of some help to you!
The best way to understand this would be to get a free 3D software and just mess around with it. Try blender or if you want something really simple, Google Sketchup is pretty fun to use as well.
Hi They are made using a 3d modelling package such as Blender, Maya, 3dsmax Blender is open source and highly recommended if you want to experiment