How is support generated when printing?

[nguyentruc1196 0]

Hello everyone, 
I'm doing a research project for a course in university, one component of which requires me to figure out how support structures are generate for each print job. Let me clarify:
Given a random 3D model, how does Cura calculate the amount and where support is needed? Does Curado it differently compared to other slicers or is it somewhat similar across all of them? 
From using Curaa it seems to me that Cura looks at each triangular surface's normal, which is stored in the STL file, but this is just my assumption, so I wonder if anyone knows how they do it. 
Any help is greatly appreciated. Thank you. 
 

[rburema 26]

Cura (as a whole) is open source, the component that does the slicing is called CuraEngine, the relevant portion of the docs that explains this can be found here. This is only a very short exaplanation, and valid for the normal support, but we also have the experimental tree-support. Other slicers have different methods of generating support.