2D stellar system editor useable as drafting

[Mutos]

Hi all,


Under the Stars of Call project of making an Elite-like and PoC-like small in-house game to learn gamedev and become able to go on more ambitious projects, the first tool I've buit is a 2D stellar system editor, designed to provide the project with a background

It has some limitations, mainly to 2D orbits, and includes some features specific to the Hoshikaze universe and useless for Celestia users, like the hyperspace Jump Points, but it occurred to me as I played with it, that it could be a good drafting tool for Celestia : first draft your stellar system under the graphical editor, then export it to SSC and refine it by hand using celestia. So came the idea of a Celestia exporter...

This version is 1.0.7, the first I consider functionnally complete enough to be released outside of the TV3D community and my Spacesims forum.

Some clickable thumbnails of screenshots :







A ZIP file is available at http://download.hoshikaze.net/sources/StarsOfCall/1.0.7/SoC-1.0.7.zip, it contains the VS2002 solution and the executable and requires the 1.1 .Net framework and TV3D.6.2 3D engine.

Next move will be to add the last two extra features that I included in my design specs : Celestia exporter and system generator.

However there is a feature I would like to add : sliders for orbital distances. I'm thinking of a double-slider control grouping both Apogee and Perigee values in a single control. Having two sliders would be possible, but poses the issues of defining their limits and scales and risking an events loop. Nothing manageable but annoying and potentially counter-intuitive for an UI. So I'm taking my time on this one, without forgetting it because I think it will be a great improvement.

Also found one thing I didn't do and ought to : rotation is not taken into account into 3D display. Got to fix that in next release !

What I would like to know by posting this into the Celestia forum is : is making the Celestia exporter worth of the work ? Are there Celestia users who would like to use this editor if it had the exporter feature ?

You could follow development more in-depth in the following forums :
Stars of Call Updates and Comments : this is where I announce new versions and we discuss SoC concepts.
Stars of Call Bugs Tracker / Features Requests : this is where people post bugs they find...

[Mutos]

Hi all,


As creator of the tool and poster, I'm the first one to answer to my own question...

Of course I think Celestia exporter would be useful, because it's my own idea ! But also there is need for improvements, mainly for the system generator.

But remember that my goal is to make realistic-looking systems as background for an Elite-like, not fully scientifically plausible systems. But to look realistic, you have to stick to some scientific plausibility. The real question is, where to draw the limit.

[bh]

This looks very interesting Mutos...I will try and give this some time.

[Rassilon]

Hi all,


As creator of the tool and poster, I'm the first one to answer to my own question...

Of course I think Celestia exporter would be useful, becaue it's my own idea ! But also there is need for improvements, mainly for the system generator.

But remember that my goal is to make realistic-looking systems as background for an Elite-like, not fully scientifically plausible systems. But to look realistic, you have to stick to some scientific plausibility. The real question is, where to draw the limit.

Its best to allow the user draw his own limits... Leave it open to phantasy and real figures...

[selden]

How soon do you expect it to be able to create 3D orbits?

I think for use with Celestia it needs to have sliders and numeric inputs for all of the 3D orbital parameters.

[Mutos]

Hi Rassilon, hi bh, hi Selden,


Thanks you 3 for your kind answers and your interest ^-^ I long for your comments !

Rassilon, the point with this editor is that it is open. There are very few restrictions apart from 2D/3D. Only Roche Limit and Roche-Hill sphere are checked on distances and orbits are pure Keplerian.

In fact, Selden, I don't intend to create 3D orbits : they just don't interest me for my game project and I have only some 30mn/day for programming it so I must restrain myself :( I'd loved to make a 3D editor but such a workload I just can't stand... after the system editor there will be a ship editor, then a navigation demo, a combat demo and a trade demo, then finally the full game integrating all 3 aspects. All that with 30mn/day ^-^

The use I saw for Celestia is the following process :
1/ Draft your system in 2D and export it to SSC,
2/ Try it into Celestia and add extra 3D values as required.

That's why I was talking of "draft" editor. I know you Celestia users are fond of 3D values, as they are the most realistic ^-^ But my purpose is only a realistic-looking game, so my specs were much lighter :)

As for sliders, I'm currently thinking them over, but they need to be in sync with all the other values and there are limit problems, so I'm not sure for now which solution I'll implement...

[Rassilon]

The 3d values are not that much more math...Mind you this is a rough draft of actual formula...

plot 360 degree coordinate system...
x = sin * cos
y = cos
z = cos * sin

vs

cartesian plane...
x = sin
y = cos

Theres plenty of papers on the subject on the net... It will in the long run be more accurate... With no need to represent this in 3d... If your thinking that you will have to implement some kind of 3d rendering engine... That will not be needed...

[Mutos]

Hi Rassilon,


The point is not on 3D itself, it's mainly on development time. The editor itself, still buggy (found a big one this morning) is nearly 1 year's work at 30mn only a day, and there is so much left to do : ship editor, navigation demo, trade demo, combat demo and final game. It may be several years before I complete the project, with only minimal specs.

Given the small time I got for dev, I already had to sacrifice many things in all fields. No modular ships with full components model and tech tree, no complex IA with formation-keeping and chain-of-command, no simulated economy, no hyperspace for the first demonstrator, no eye-candy special effects (I use only 1% of the TV3D rendering engine) and so on... and no 3D as it was not essential to this project. My goal is to demonstrate a gameplay, that will be cool even on 2D.

And moreover, going fully 3D means much more. It means 3D orbital parameters (actually used code borrowed from a 3D orbital editor I made some years ago in VB6, but choose to use only 2D part for sake of time), 3D course computing (acceleration with half-turn at mid-course and velocities match), 3D thrust and orientation with all the problems that can arise (gimbal lock), etc etc etc...

I thought about the Celestia exporter just as an extra cool feature but not as a primary goal of the editor. As for the exporter UI, I'd see two ways : either you are given a textbox in which the SSC code is written and which you can copy/paste into your own SCC file, or an SCC file writer. Which has your preference ?

Another thing is, what time reference do you use ? I set one that fits with my project (01/01/2250) but has surely nothing to do with any "official" one :twisted:

[Rassilon]

Well all of that is up to you of course... I was just speaking of orbital elements pertaining to Celestia figures... When making an exporter you should probably try to make it use the same coordinate system as Celestia to give those who use your tool minimal effort on the part of editing the ssc text file otherwise they might not use it in the first place... Just food for thought... You might actually be wasting precious time implementing an exporter for Celestia... I ran into that when I was working on the Doctor Who Project... Trying to make a Celestia exporter I found that I was missing alot of the critical features Celestia needed to calculate properly the different orbital elements... Baycenters for binaries etc... Most of my calculations were a 'faked' 3d representation...Mostly based on a 2d plotting system... Ive gotten better however with the current project I work on... which roughly ends up being 30 mins a week or less... The project is entitled Cosmic Explorer... So yes I do see what it means to look into the future and see a few years in the making

Other than that cheers to all the effort... It looks like a promising project!

[Mutos]

Hi Rassilon,


There's also one reason for which making a Celestia exporter is important for me. I once used Celestia extensively for making shots of systems in the Hoshikaze 2250 universe, which ended in my site. So for me it's the opportunity to return to the Celestia community some of the the help it gave me in developping Hoshikaze ^-^ Mentionning also that I currently use lots of Celestia textures in my Stellar System Map Editor.

What I think I'll do is only just adapt my existing text writer to the Celestia file format and make it into an SSC file writer. The goal is to open the resulting SSC file right into Celestia and have a working system, however in 2D.

However it would seem Adrian, lead tester on the app, just discovered a bug in orbital speeds. I'll look at that but it would be cool to have your comment. He mailed me that :

One problem... you have orbital speeds back-to-front... an object speeds up as it gets closer to the perihelion and slows at the aphelion so that the resultant triangle from ABprimary has an equal area and is formed within an equal time... your app is the other way with objects speeding up as they move farther out on ellipitical orbits!

And he seems to be right ! I'll have to rewrite my movement equations. I wrote them some years ago for the 3D editor, from the actual equations, but they seem to be wrong somehow...

The other bug I discovered yesterday was related to .X input. Sometimes you enter a .X filename that exists but that TV3D is unable to load. The program throws an exception but if you say OK it continuesto run, just with an empty object instead of the intended .X object. I discovered it when I tried to convert a 3DS mesh into .X and ended up with a malformed file with zero vertices and polygons.

[Mutos]

Hi all,


Here are screenshot of a test system in both SSME and Celestia, to help you see what's going on. I think release of a working exporter is soon, maybe just one week or two, version number will be around 1.1.0.15...

The screenshots show a system with regularly spaced planets to test the ArgOfPericenter and MeanAnomaly variables. The goal was to have the two rings of planets at the same place at reference time, one with same circular orbit, the other with a series of regularly spaced elliptical orbits.



For now there is still a problem with reference dates. Celestia uses 01/01/2000 as reference date where my editor uses 01/01/2250, which is the date where the game begins... So I'll have to export the Epoch parameter in SSC files.

The corresponding SSC code is shown below, it contains in comments the original INI format from the editor. If you find any other problem with the code below, please tell me before I release the final 1.1.0.xxx version.

Code: Select all

#==========================================================================
#  Stars of Call - Stellar System SSC (Celestia) exportation file
#
#  File format warnings :
#    - 3D objects :
#        Stars of Call SSME uses .X files for objects,
#        They are exported as .3DS references in SSC files,
#        You have to manually convert .X files to .3DS format.
#    - Textures for spherical objects :
#        Stars of Call SSME uses .JPG files for textures,
#        They are exported as .JPG references in SSC files,
#        Texture reference axes are inverted.
#        You have to manually convert the texture axes for same rendering effect.
#        Use procedure : Horizontal Pivot + Right-hand 90?° Rotation.
#
#==========================================================================

#==========================================================================
#  Primary data is not part of SSC format
#  Original data included here only as reference
#==========================================================================
# 
#  [Primary]
#  Name               = Test
#  Mass               = 1.99000000E+30
#  RotationPeriod     = 2.19283200E+06
#  Radius             = 6.95990000E+08
#  Texture            = DefaultPrimary
# 
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-000]
#  Name               = Orientation-000
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-000" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-060]
#  Name               = Orientation-060
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 60.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-060" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 6.00000000E+01
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-120]
#  Name               = Orientation-120
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 120.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-120" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 1.20000000E+02
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-180]
#  Name               = Orientation-180
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 180.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-180" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 1.80000000E+02
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-240]
#  Name               = Orientation-240
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 240.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-240" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 2.40000000E+02
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Orientation-300]
#  Name               = Orientation-300
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 300.00
#  Apogee             = 2.99200000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Orientation-300" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          1.83647083E+00
    SemiMajorAxis   1.50000000E+00
    Eccentricity    3.33333333E-01
    ArgOfPericenter 3.00000000E+02
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-000]
#  Name               = Offset-000
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 0.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-000" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     0.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-060]
#  Name               = Offset-060
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 60.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-060" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     60.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-120]
#  Name               = Offset-120
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 120.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-120" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     120.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-180]
#  Name               = Offset-180
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 180.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-180" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     180.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-240]
#  Name               = Offset-240
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 240.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-240" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     240.00
  }
}
#==========================================================================

#==========================================================================
#  Planets are converted to SSC format
#  Original data included here only as reference
#  Caution : SSME only uses .JPG texture files
#==========================================================================
# 
#  [Offset-300]
#  Name               = Offset-300
#  Mass               = 1.99000000E+27
#  RotationPeriod     = 8.64000000E+04
#  RotationOffset     = 0.00000000E+00
#  MajorAxisDirection = 0.00
#  Apogee             = 1.49600000E+11
#  Perigee            = 1.49600000E+11
#  AngularOffsetAtT0  = 300.00
#  Radius             = 6.95990000E+07
#  Texture            = DefaultPlanet
# 
#==========================================================================
"Offset-300" "Test"
{
  Class "Planet"
  Texture         "DefaultPlanet.jpg"
  Radius          6.95990000E+04
  RotationPeriod  2.40000000E+01
  RotationOffset  0.00
  EllipticalOrbit
  {
    Period          9.99648100E-01
    SemiMajorAxis   1.00000000E+00
    Eccentricity    0.00000000E+00
    ArgOfPericenter 0.00000000E+00
    MeanAnomaly     300.00
  }
}
#==========================================================================

#==========================================================================
#  Stars of Call - Stellar System SSC exporter - End of File
#==========================================================================


[Paolo]

Hello Mutos

Do you plan to release the software as open source?

Rassilon is involved in a similar project, and I've offered him my support.

Why don't you consider a merge of the two.

Kind regards

[Mutos]

Hi Paolo, hi all,


Merge would be a nice idea, except that my project is mainly for Stars of Call purposes : to give content developpers a tool to easily make background stellar systems. It occurred during test that it could also be used to draft systems for use in Celestia, but it's not the project's main goal.

But of course I'll release it open-source and you can peek into it to poke into your own work ^-^ And if there's any question, I'd be glad to answer you :)