Page 1 of 1

tle2ssc: Celestia GNSS GPS Galileo Glonass Beidou TLE to SSC

Posted: 22.05.2022, 04:48
by jebba
Hello folks,

I'm glad to see that Celestia is under active development once again. Thanks! :)

I created a script that converts TLEs into the .ssc file that Celestia reads. I wanted to see the various GNSS satellites in Celestia.

celestia-gnss-orbits.png
GNSS Orbits in Celestia from TLE


Code is here:

https://spacecruft.org/spacecruft/celestia-gnss

Happy hacking,

-Jeff

Posted: 22.05.2022, 09:38
by Lepestronik
Welcome, Jebba!

Thanks for your stuff, it will be useful!

I have read the description of the repository and I can tell you something about creating .cmod 3D models.

Go to File --> Export --> 3D Studio (.3ds).
Save the file, such as galileo-gnss.3ds.
The galileo-gnss.3ds file created this way didn't render in Celestia. :(

The next thing you need is to use the Anim8or program
https://www.anim8or.com/download/index.html
with the extension by selden installed to export to .cmod
https://www.anim8or.com/scripts/selden/export_cmod_plugin.a8s
If you are a *nix user, you can run it with Wine.

Then:
1) Object -> Import... and select your "after-blender" .3ds
2) Object -> Export as Celestia: plug-in (*.cmod_mesh)

You will get two files: the first one with materials, the second one with meshes. Then add the second file to the end of the first one and save it as .cmod.
This will be .cmod in ASCII mode. You can modify it as plain text and use it with Celestia directly or modify it and save as much smaller binary .cmod file using cmodview program (for Celestia 1.7.0 it may come bundled, or download it here: https://celestia.space/utilites.html ).

You can read about texturing here (see Anim8or: Texturing the model section):
viewtopic.php?f=21&t=17427

Good luck!

Posted: 22.05.2022, 20:41
by jebba
Hey Lepestronik,

Thanks for your comments. :)

I was able to convert the galileo.obj file to a galileo.cmod file directly, without having to use Blender. The Celestia tool cmodview was able to read .obj directly and save a working .cmod file. I didn't add the textures yet, but it appears that can be done in cmodview as well. I don't use proprietary os/apps.

I haven't found (or really looked for) 3D models of the other satellites yet.

Thanks again,

-Jeff

Galmon Observers SSC

Posted: 24.05.2022, 03:39
by jebba
I added a script which makes SSC output from Galmon GNSS Project observers' latitude / longitude and plots them on Earth.

https://spacecruft.org/spacecruft/celestia-galmon

Galmon FYI:

https://galmon.eu

https://galmon.eu/observers.html

-Jeff