this script makes a SkyBox based on any sprite that is set for 3D use. It will automatically size it self based on the room width and room height. as for how high it will make itself, that will be the third argument. The first two arguments are the sprite you wish to used as the sky view. an example of the code can be seen below.
The SkyBox must be used with either the 3D cameras on available from IceSpaceVolcano or 3D must be activated and a projection must be made with the orientated with positive Z up and view in the XY plane. I would advice the former if you have limited 3D experience, unless you are a masochistic. Note- the camera included in the package is an incomplete and still under development, it will not work. It will be removed from the package shortly after this upload, but for now just do not import it from the file!
to make stuff in the game download the Digagomi software.