Celestia Forums

Is it possible to draw interstellar routes in Celestia? I mean visible lines from star to star?

How can we save markers on stars and other stellar objects?

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by selden » Today, 00:44
I know of two ways to draw routes between stars.

The easiest is to replace the file "asterisms.dat" with one which draws your routes instead of constellations.

Another is to define a Nebula using a CMOD mesh which contains vertices which are the xyz locations of appropriate stars and line declarations to draw lines between pairs of vertices. Learning how to generate the correct xyz coordinates isn't trivial.

I've done the latter to illustrate the trade routes of CJ Cherryh's Alliance/Union stories. That Addon is available at http://www.classe.cornell.edu/~seb/celestia/pell/index.html#4.0

I'm currently working on a project to similarly illustrate the wormholes of the Orion's Arm Project. See http://www.orionsarm.com/forum/showthread.php?tid=2325&pid=25736#pid25736

I've written several Fortran programs to process a .CSV database of interconnected stars. The programs generate a CMOD mesh, .STC and .SSC catalogs, and marker/label scripts. I'm not sure my utilities are in a state that'd be easy to use by anyone other than myself, though. Among other things, they require Cygwin to be installed under Windows, for example, including gcc and gfortran. In principle they should work under either Linux or the Ubuntu bash environment of Windows 10 Anniversary, but I've never tried either of those environments.

Turning Marks on and off is much easier than generating a model. You can use either a Cel or CelX script to do that. Here's an example CelX script
Code: Select all
  celestia:unmarkall()
  celestia:find("Tau Ceti"):mark("#ffff00","circle",5,1,"Tau Ceti" )
  celestia:find("Zeta1 Reticulae"):mark("#ffff00","circle",5,1,"Zeta1 Reticulae" )
  celestia:find("HD 12042"):mark("#ffffef","circle",5,1,"HD 12042" )


Details of Cel and CelX scripting, including their mark and unmark commands, are available in the Celestia Wikibook. See
https://en.wikibooks.org/wiki/Celestia
and https://en.wikibooks.org/wiki/Celestia/Celx_Scrip ... _Lua_Methods#CEL_command_index
Selden

Added after 1 hour 17 minutes:
Selden, thank you very much, modifying the "asterisms.dat" is perfect for me!

If I may suggest it would be wonderful to have a user friendly option in the GUI to create semi-permanent (I mean saved and modifiable) interstellar routes and markers.

And with the integration of ESA Gaia star data Celestia would be the first interstellar navigational software in the history of human civilization... :)

I append star routes to to the astersms.dat file at the end, or simply replace it depending on what I am doing.
I keep a copy of the original of course.

One of my projects is adding a journey function.
I am currently working on copying the constellation functions, renamed journey.
My goal is to be able to select a star, then add it to an existing journey, while running.
though that will require getting celx to be able to make files, which is not always fun.

In progress, but progress is slow because of life.

Janus.

Nice! Right now modifying the asterisms.dat file is fantastic for me...

John71 said: The easiest is to replace the file "asterisms.dat" with one which draws your routes instead of constellations.

What text do I place in the asterisms.dat file to draw lines? Is this documented somewhere?

I need to draw 3D lines as I receive UDP packets with my trajectory state information. Is there a way to draw lines in Celestia, yet?

Thanks,

NASA_SimGuy wrote:What text do I place in the asterisms.dat file to draw lines? Is this documented somewhere?

You can check the file yourself. It's trivial.

NASA_SimGuy wrote:I need to draw 3D lines as I receive UDP packets with my trajectory state information. Is there a way to draw lines in Celestia, yet?

I suppose it's possible using celx scripting, it supports gl commands.