In my game The Master's Eye there are several missions which use the ScatterSky object combined with a TimeOfDay object. But there is the nasty problem that it is impossible to use the SkyBox object as a horizon/background (for the simple reason that this will cover the sky generated by the ScatterSky) and without this the transition from the terrain edge to the background is rather immediate (it is just from terrain to sky). You can modify the terrain or add a line of trees or somthing like that, but it is a workaround which I find quite lame.
The first thing I did was adding alpha information to the cubemap images and tried to use the SkyBox with these images (material with translucency set), but this did not give the desired result, I discovered that the SkyBox object was not able to handle transparancy. Dug any deeper and I saw that lighting was disabled for SkyBox materials. I enabled it and it did seem to work! Unfortunately, while running a debug build I got an assertion, stating that not all shaderconstants were defined for the skybox material . Also the lighting of this skybox was not that great at all, but okay. I decided to keep using this despite of the assertion when debugging, until I played this level, which also used the LightRay post effect, and I watched the sun sinking between the terrain and the skybox and the LightRay post effect did not perform well either. At that point I decided to create some sort of a SkyBox object that could be used with ScatterSky/TimeOfDay and here it is: the SkyLine object.
The SkyLine object
The SkyLine object is basically a SkyBox object that can handle transparancy (and do some other fancy tricks as well). Because of this it can be used with the ScatterSky and TimeOfDay objects; night sky cubemaps and moon are handled as one would expect (behind the skyline). The BasicClouds and the CloudLayer object both have a new option added, so they can be rendered behind the skyline (not necessary but just like the real thing). Finally the SkyLine object has an option to generate a mask that can be used with the LightRay postfx, so that the lightrays are covered by the skyline, giving a more realistic feeling. To demonstrate all of this I have a nice demo video, just take a look:
I want this thing, how do I get it
In contrast to the Volumetric Fog and the DoorClass objects (which are free), I have decided that this SkyLine Object Pack is available for the reasonable price of 5 Euro (approx. US$ 5.57) and can be obtained from the R.G.S. site here.
A step-by-step installation guide is included in the download as well as a sample cubemap and user manual.
Thanks for reading