Caelum is an add-on to the OGRE Graphics Engine, which simulates an atmospheric sky with a sun. For more detail visit this post on Ogre's forum. Unfortunately, Caelum is written in C and then it can't be integrated with NeoAxis Engine. So we developed Caelum for NeoAxis which is a Caelum's translation in C# and which is specially conceived for NeoAxis.
Features: