Using Blender Render and Cycles
Blender has two built-in render engines: Blender Render and Cycles (the new render engine). In the middle of the Info Editor (the bar at the top of the interface), you’ll find a button that lets you select the render engine you want to use. By default, Blender Render is selected. If you click the button, you see two other options: Blender Game and Cycles. Blender Game allows you to play with real-time graphics as though Blender were a game engine. You can create games and interactive content that will run in the Blender Game engine.
Blender Render is the old engine, as it’s not receiving further development, even though it’s useful and can be used to create stunning results. (Cycles will replace it at some point in the future.) This engine allows you to set up materials that simulate reality, but it’s just a simulation, so achieving realistic results can be difficult. Although Blender Render is not a realistic render engine, if you control its parameters, materials, and lighting correctly, you can achieve pretty realistic renders with good quality. Due to its nature and because it is not as realistically accurate, it’s also a lot faster than Cycles, which makes it a nice alternative when you want to do nonrealistic rendering or when you’re short on time.
Cycles is slower than Blender Render, but it’s a physically based render engine, so light and materials behave realistically due to mathematical functions that simulate real light behavior. Light bounces off surfaces and generates indirect lighting, just as real light does. Getting a realistic result with Cycles is much easier than with Blender Render, but it requires different skills, because Cycles is designed to use materials built with nodes. When you’re creating very basic materials, however, you don’t really need to use nodes. Cycles also lets you render by using GPU, so if you have a good graphics card, you can speed your render times considerably.
You need to decide which render engine you want to use before you start building the materials for your scene. For the most part, the two engines are incompatible, and their lighting systems are quite different, so switching between the engines after you have your materials set up usually is not a good idea. You would have to rearrange your materials or even build them again from scratch.