Well, Unity would be the best if the OP just wants to make a game.

But he said above, he wants to learn the programming behind it.

I want to learn the logic of creating 3d models and using them through a programming language

so this is right?

[quote name='heiro' timestamp='1333815456' post='4929069']
Hmm cool. So if i have a human body and i want to make it walk, i can do this using opengl etc right?

[/quote]

yes, and no. you use openGL or DirectX to render a scene. so, let's pretend you are only using c++, and openGL, no other engines. if you have a human body, you first select a format you want to load it in as, does this format support animation, skeletal, or geometry animation?, how is the data stored, how do you store the data once loaded. do you use the fixed pipeline, or write shader's. do you do the animation on the gpu, or on the cpu?, once you've loaded the data, now you need to draw it. so you need to understand matrix's, projection matrix's, and how to efficiently render your model.

If you want to make a game, use unity, or something similar. writing a 3D game with only openGL/DirectX require ALOT of knowledge of mathmatic's such as matrix's. possibly even quaternions, triginometry, and such. you need to understand textures, lighting, framebuffers, etc. it takes alot of time to fully understand an graphics api, to understand how to use shaders efficiently, how to animate characters, their is no magic functions to load, and animate with openGL/DirectX, they are the closest you can get to communicating with the hardware these days.