Hi people, short of booting up my havy non-work gaming rig and extracting, de-converting and checking the stats myself i thought i'd see if what i need exists anywhere in HLP. and if not, maybe it would be good to have a thread for those that search. 
What's the reccomended size in Truepace units (radius or circumference) and are there any prefs on texture dimension for a skybox texture? #
Another quick point i have always pondered, can skyboxes have sub-objects? why you ask, don't worry about what i'm hypothesising. Just that if it works it'll be quite cool 
Tiled starfield or spherically mapped skybox? Also, required resolution depends on field of view settings. Ideally, the magnification of the texture on the skybox should be as close to 1:1 when it appears on the screen. If you have a field of view of 90 degrees and your horizontal resolution is 1024 pixels, then you need 4096 pixels for equator and 2048 pixels between north pole and south pole. If your field of view is 45 degrees and horizontal resolution is the same, you need 8192 pixels for latitude and 4096 for longitude.
Of course, textures of this size are only supported by relatively recent hardware. Even 4096x2048 had some problems with the Cardinal Spear planets when older GPU's only supported texture dimensions up to 2048^2.
So, for spherical mapping - if you really want to, you
can go as high as your GPU supports I guess. However, the resolution needed will depend greatly on what exactly you want to have mapped spherically... for example, nebulas can be tricky in the sense that their resolution doesn't necessarily need to be sky-high, but compression artefacts will be easily noticed. Based on my experiments, nebula layer mapped spherically works fine at 2048x1024, while looking slightly better at 4096x2048 at quadrupled texture size.
The mediaVP starfield skybox uses a square texture tiled to the surface of the sphere from six directions (kinda like a rounded cube but not at all). It's a pretty clever setup and 2048^2 sized texture is sufficient for very good detail at default fields of view. If at some point we get a dynamic field of view (ie. zoom) instead of a cmdline option, things might change a bit.
And yes, skyboxes can have subobjects... kinda. The subspace model works like that, it has two counter-rotating sections. I made the nebula-starfield skybox that way, essentially there's the outer shell with the tiled starfield and inner shell with a spherically mapped nebula texture on it. However, I don't know what the limitations are about actually putting objects like planets inside the skybox, apart from a plane with a planet texture slapped onto it. I tried putting an actual planet model inside a skybox once, and I ended up inside the planet...
Model size... I'll leave that for someone who knows how to answer.
