Prcise type of engine and funcionality of Blender Internal (help)

Hey guys :slight_smile:

I am currently writing my Bachelor Thesis and I want to compare Blender Internal and Cycles. Now my problem is that i don’t seem to find any reliable information concerning what exact type of engine BI is. I already know that Cycles is an “unbiased, physically based, path tracing engine” and blender internal is a “biased rasterisation engine”.

BUT: Don’t they both use ray tracing? And does the internal engine not also support indirect light to some extent?

Right now it seems to me that Blender Internal is just Cycles set to one light bounce, which of course I know is not the case but I couldn’t find any literature that would clarify which Type of engine BI is. In the Froums there are sometimes even contradicting definitions… -.-
Also the definitions are oftentimes like “BI is just not as good”, “Cycles is more accurate”, “You have to fake a lot in BI”. That kind of information doesn’t suffice for a Thesis i fear ^^

Some help would be highly appreciated :slight_smile:

Thanks in advance


PS: Before you ask: I already dove into some serious literature concerning the topic, but since I don’t know which type of engine I’m searching for, my quest has thus far been rather daunting :frowning:

There is no standard name for it. All renderers use a mix of techniques and Blender Internal is no different. Biased and unbiased are often used as a buzzwords without exact meaning, but can give you a rough indication about the types of algorithms used. A renderer being “physically based” means that it’s more so than some other renderers, but all are based on physics to some extent.

Blender Internal uses algorithms that tend to trade accuracy for speed: rasterization, A-buffers, shadow maps, point based SSS and GI, ray tracing only for specular and AO. Some of these algorithms are intrinsically biased and some not. The shading models in Blender Internal are less physically accurate than in Cycles and similar renderers, sometimes due to the choice of rendering algorithms, often just because at the time it was written this was not as well documented and not considered as much a priority as it is now.

Thanks mate, that helped me out :slight_smile:
Thanks for the link, too. Always happy to get some additional sources <3