2D Layout + 2D Spritesheets

Hi everyone,

I am going to use Unity mainly for 2D games so I am very interested in Unit 2D system. Last week I spent many hours with learning Unity and I very appreciate a good documentation, but I have several problems. Since I've been using Cocos2D-x so far I am expecting some features which are actually great in Cocos2D:

a) layout system (virtual resolution, so placing sprites is invariant to real resolution and even to different aspects, aligning sprites to display edge etc.)

b) spritesheets (I am using TexturePacker [btw: coolest tool for packing textures] and loading atlases according device resolution with content scaling, this is working perfectly and I have complete control over the process).

After many hours of reading the documentation I find document how to create sprite from 2D texture with option to slice multi-sprite texture manually. This is not useful actually since atlas can be changed whenever (I made some test and auto detection of slices does not work for me too much). Then I found Sprite Packer in Unity - this is better option but I cannot find how create textures for different target resolutions.

So my questions are these:

1) How Unity solves the problem of Sprite layouting across different target resolutions?

2) How can I create and manage spritesheets for different devices? How can I control which texture will be used and so on?

I think this is a crucial for making multiplatform/multidevice 2D apps and I cannot find anything about that (except some threads on forum which are using Third Party libraries for 2D in Unity [I want to avoid this since Unity has direct support now]).

Except this I consider Unity (2D/3D) as very cool tool (especially animation system, physics, scripting).

Thanks for any hint.

Jiri Formanek