Blender it's a huge 3D design platform that can be used as an extension of all specialized CAD programs.
Any 3D model can be imported in to blender and can be rendered in to any 2D image or animated video, the use of lights, cameras, and custom textures make blender the finest way to make high quality blender in any system.
Blender capabilities are in constant grow and new users can found alot of information about how to start using the program. Here for example is a quick 3D model rendering tutorial:
Configuring the Render tools
Creating a 3D space and preparing the model.
Creating a camera and some lights.
Here you can find some hep for your own render, like a iron texture and a 3D model of a gear just like in the tutorial.