The long and short version is: Use a 3D program. Blender is free, after all.
1- How can i play with the dimensions of the 3d box with numbers, such as pixel or cm ?
You can't. All units in PS are relativeand normalized to the scene.
2- How can i create 3d box and add different textures to different part of the box? I found CUBE MESH PRESET in the forums but no download link, EVEN IN THE DISCCUSION itself
That's what 3D-programs and UV layout tools are for. Creating an unfolded cube UV set is a 10 second thing. Here's one: http://www.mylenium.de/_temp/uv_box.zip.
Where i can modify the render quality or such a thing if it exists?
Select the Scene root to change the render mode and quality and also check the 3D section in the prefs.
Mylenium
