Celestia Forums

Hello:

I understand how this feature request could be problematic, but I figured I would throw it out there anyway and see if anyone has any ideas. It might be a rarely-used feature.

I enjoy using the "primitive-earth" textures, which include a texture for both the Earth and the Moon shortly after the theoretical large-body collision that may have resulted in the ejection of the material that became the moon. These textures include lots of night-side glowing lava, and the Moon and the Earth are much closer to each other.

So, it's natural to want to be able to select the "primitive" versions of the earth and the moon as alternate surfaces. I already have this working, except that I can't change the distance of the moon from the earth in an AltSurface definition in the .scc file. If I include any parameters other than texture parameters in my AltSurface definition, the alternate surface won't load.

Would it be possible to allow a modification of the moon's orbit in an AltSurface definition for the moon?

Thanks,
Tim

Tim,

Orbital parameters are defined in SSC files.
If you want the moon (or any orbiting body) to be at a different distance, you should change its orbital parameters in its SSC file, not in its texture.

I think the "right" way to do it is to define a "PrimitiveEarth" with "PrimitiveMoon" going around it; both with Beginning and Ending directives. The "modern Earth" would need to have an appropriate Beginning directive added to its definition.

Does this help?

I see your point about the Beginning and Ending directives. Since the views that I want to see differ (in real life) as a function of time, I should use Celestia's existing provisions for displaying different things at different times for my purposes.

From a user interface perspective, I preferred being able to right-click on Earth and just select the "primitive" version of Earth. It will be slightly more trouble (but still not a terrible burden), to use the time controls to go back to an ancient time.

As for the SSC file, I knew that, I just typo'd SCC instead of SSC. The AltSurface declaration already appears in my solarsys.ssc file. My hope was that the AltSurface implementation could be extended to allow the specification of alternate orbital parameters in addition to alternate textures. But you have convinced me that the Beginning and Ending directives are the better approach.

Thanks,
Tim

Don't forget that you can record "favorites", either in the favorites menu or as Cel:// URLs, so you only have to use the "set time" menu once. Personally, I prefer using Cel://URLs, since I can put them on Web pages and don't have to start Celestia and fumble through the menu that I forgot to update...