I have been developing educational activities for Celestia that draw new textures to replace existing ones at some point in the Celestia future. For example, in the year 9998, I have a new giant sun drawn (a big Red Giant) that takes up the volume of most of the inner solar system. The Red Giant Sun is simply a planet that uses emissive true and is centered on the existing Sol, with a radius of over 1 au. In order to draw it only after the year 9998, I have inserted a Beginning command in its ssc file. It works fine and does not appear until 9998. However, to my dismay, Celestia still treats it as if it was present, although invisible, in our present time. For example, when I try to select the Sun or Mercury or Venus with a left mouse click in the year 2003, all I select is the Red Giant Sun (since it will have enveloped the inner planets). Celestia is not drawing it until the proper time in 9998, but assumes it is in space at that spot, even before the ""Beginning" date and is allowing me to select it (even if I don't want to).
Other objects I have placed in the future also suffer the same problem. For example, in the year 9999, I "end" the current planet Jupiter with an Ending command in the solar.ssc file and start a new, changed Jupiter (to reflect the presence of a Red Giant sun nearly), 1 second later, using a Beginning command. Again, it works fine and does not appear drawn until the prescribed time, but when I click on Jupiter in the year 2003, I get either Jupiter or the New Jupiter selected, even though the new Jupiter is not supposed to be there yet.
Is there something I can do about this, short of dragging all the Activity add-on files out of the extras files when I'm not using it?
Frank
