Cycles Versus Blender Internal
When it comes down to rendering your project I would imagine that the choice of render engines comes down to what is available and what your trying to achieve. After all you put in a great deal of time and effort in your modeling, setting up materials and lighting, so it is only natural to want the best render possible.
With so many render engine out there your choices become very broad. You have external renders such as Luxrender, Yafaray, Aqsis, and Mitsuba. Each one offering rendering optimizations. Some are biased and others unbiased and some are even both. Whatever that means.
Blender offers two choices built in if you don’t count the game engine. Blender internal and cycles. Good Ole internal, blender internal was the only renderer in Blender when I first started using it. Blender internal offered fast but not so accurate realism which enable me to view my renders quickly and adjust on the fly. ( though my renders were not that good) Then came cycles which allows real time feedback when adjusting materials, lighting, or what have you in your scene without having to render and re render after every scene change. What is the difference between the two?
Blender internal is a biased render engine which basically means it ignores some effects that lighting would have on a scene. This causes the artist to have to fake things such as bounced lighting and full global illumination. The trade here is you have to spend a little more time on your scene, you will have to study and tweak your lighting according to a reference image you are hopefully following to achieve a realistic result. The biased nature of blender internal allows for faster renders because it doesn’t have to calculate all the light passes and bounces but leads to a less than accurate result.
Cycles is a unbiased render that uses algorithms to come up with a mathematically correct result. This is why you render starts out with so much noise as cycle calculate the light passes and bounces thus giving you a physically accurate render. Here the trade is less time on your scene (maybe) and more time waiting on your render.
That is about as technical as I can explain the difference between the two. From my experience I can share this, because time is such a precious commodity, long waits are not my thing. I have heard of people waiting 24 hour for an animation in cycles that was 16 seconds long. I myself have waited 4 hours for a 16 second animation in cycles on a scene that took me 1 hour and 20 minutes two complete.
Living is this age of instant everything fast Internet and faster computer we want to be gratified with quick results no fuse no wait. Now since my cpu is faster than my gpu for me and many others gpu is not an option. To me an image in cycle 1920 x1080 at 50 percent and 140 samples rendering in 105 seconds or 1minute and 45 seconds seems extreme or is it?
In the video above the opening scene was rendered in both cycles and blender internal. The cycles render took 4 hours as mentioned earlier, the same scene in blender internal took 58 minutes. I like cycles and blender internal and I believe there is a place for both as they have an equal amount of pros and cons. When doing your next render consider your option carefully based on what you are trying to produce and the amount of time you want to a lot. Enjoy your Blender experience and remember sharing is learning.