Ok, so I've already waded through a bunch of questions around this, and it's just making me even more confused.
Let's say I am trying to model a card table in a 2d game. Behind (beneath) the table is a quad with a floor texture. The "table" is a sprite that is just an oval (using basic shapes at this stage until I have real artwork).
I've read plenty of questions on how to scale to different device resolutions. And, that is certainly one way to do it (bit seems like a lot of work). I've also read posts about changing the size of the orthographic camera to match the device (this seems easier). But i'm left not quite understanding what the frame of reference is.
Let's say I design the game to work in 16:9 at HD resolution (1920x1080). I size the "floor" to fill the entire space (and maybe extend a little beyond). I size the "table" to fit within a smaller portion of that space.
If you have a fixed scene (ie, not a scroller), and you want the contents to fill the entire viewport, what is the best way to go about this? Scaling the objects, scaling the camera?
As far as units, what's the best choice? 1 PPU? What rule of thumb do you use when choosing PPU? What are the reasons to choose different PPU's?
I think i'm missing the forest for the trees. I understand so many of the basic concepts from reading so many questions, I just don't know how to put them together and when to choose which method.