Basically, what I have is a tile-based world that is managed as cubes, so all of the planes are either going to be flat to the front on the X/Y axes, or sideways along the Z/Y or Z/X axes.
What I'm saying is that I'm using cubes. if each cube is facing straight forward, each face of the cube lies on a plane that goes either parallel or perpendicular to the screen. Therefore, if I'm looking at the front face of the cube, the Z of that plane is constant for each point on that plane. So all I have to do to define that face of the cube is give it minimum and maximum X values, and minimum and maximum Y values.


I also found the two-point equation of a 3D line:
Code:
 x-x1       y-y1      z-z1
------- = ------- = -------
 x2-x1     y2-y1     z2-z1
Could I also use that and then solve for the unknowns?

Like...If I'm using that same face of the cube, I know the Z value of the collision, because Z is constant for all points on that plane. I just need to solve for X and Y of the line at that Z value. using the two-point equation.

Does that make sense or is my logic completely wrong?