selden wrote:Remember that Celestia is optimized for 3D realtime, rather than 2D with memory. They're quite different requirements.
The drawing data does not have to be generated separately, it can recycle the 3D realtime data from the normal rendering buffer. Yes, extra memory is needed for plotting the path curve like this:
![Image](http://www.provr.fsnet.co.uk/track_overlay20060825.jpg)
selden wrote:I think a substantially different new orbit path drawing routine would have to be written: one that draws lines at the radius of the parent body's surface in realtime (rather than calculating the path once in advance as it is now) and which limits the total length of the path to three orbits; or, better, to the value of some parameter specified in the config file.
Yes, you are 100% right, Selden. But again the data of the orbit path is created anyway in the realtime rendering process, all it needs is a plotting routine that utilise this data.