I’m working on a display library which in most cases works on a 2D plane but it has some components which display 2D projections of a 3D space.

This domain has the notion of Position, Size, Position3D and Size3D.

Position and Size are straightforward:

data class Position(val x: Int, val y: Int)  data class Size(val width: Int, val height: Int) 

but when I introduce the 3D variants height is no longer self-explanatory:

data class Position3D(val x: Int, val y: Int, val z: Int)  data class Size3D(val width: Int, // this is OK                   val height: Int, // is this the Y or the Z axis?                   val depth: Int) // is depth universally recognized? 

Is there a best practice for this problem?

I can work around it by doing something like this:

data class Size3D(val xAmount: Int,                   val yAmount: Int,                   val zAmount: Int) 

but it feels a bit hacky.

How can I solve this?