Given some data points in 3D, $X\in\mathbb{R}^{n\times 3}$, could one say that$$Y=XP,$$ for some $P\in\mathbb{R}^{3\times 2}$ actually corresponds to a particular viewpoint on a 3D data? Basically, does any $P$ correspond to a viewpoint, which is a 2D projection?I'm trying to understand the relation, and I'm interested in whether one is left with more degrees of freedom by choosing $P$, or simply by choosing a viewpoint. What is the relation between the two? 
3D to 2D projections, a generalization
linear algebra;matrices;high dimensional