Also known as “Blender Internal” (or BI), this is Blender’s original render engine with source code from the early 90s. It’s a conglomeration of new (ish) and old rendering technologies that are brought together, including raytracing, subsurface scattering, shiny reflections and even a primitive global lighting function, in general it’s a very fast render engine for most of its functions and is characterized by non-photorealistic (NPR) rendering. But it suffers greatly from photorealism. BI was developed at a time when realism could only be achieved by illusions. Using tricks and hacks to fake the properties of reality, but you probably haven’t heard much about BI in recent years, let alone used the renderer. Why is BI so little known?
Starting in 2011, Blender will also be offering a new, innovative renderer called Cycles in its toolset. It is a huge step forward in terms of realistic rendering, with full “global illumination” and physically accurate calculations: You’re wondering, “Why is it a separate engine and not an upgrade to BI?” Sometimes it’s just easier to start from 0 than to change an existing thing. BI has years of development with many features and upgrades behind it. As time went by, it became more and more difficult to continue the development and so Brecht decided to develop a new engine from scratch, which enjoyed great popularity and quickly became Blender’s first render engine. Cycles has earned a considerable reputation in the computer graphics industry. In fact, other 3D software developers have even ported it to other applications such as Cinema 4D and Rhino.
So why not categorically complete either engine?
This question can be answered with another question: Since when are alternatives something bad? The reality is that BI and Cycles make things so different that they don’t really compete. Rather, they are two tools that have their respective advantages.
When the Blender Renderer is a good choice: