Whar are the two types of projectionns?

Not sure what you mean, but if you're asking about projecting 3-D models onto a 2-D display, there's orthographic (straight on), isometric (depth is drawn at a fixed angle), and perspective (like we see). I had the pleasure to code all 3 of those types, in Motorola 68xxx assembly language, back before there were display libraries. Perspective is especially challenging, with matrix math, dot product to know which way a surface is pointing, and determining obscuring. Good times.