How to create objects for Celestia

[Lalla]

Hi all!

I've found beautiful nebulas image. What can I use them for Celestia?
Thanks in advant for help.

[selden]

To put a picture into Celestia, you have to put it on the surface of a square, flat model and place that model within Celestia.

Instructions for how to do this can be found at
http://www.lepp.cornell.edu/~seb/celest ... board.html
but it might help if you also read
http://www.lepp.cornell.edu/~seb/celest ... intro.html

Some pictures of Nebulas already have been made available for Celestia at
http://celestiamotherlode.net/catalog/m ... ebulae.php

[Lalla]

Thanks for your help, Selden.

[Lalla]

I've troubles to assign surface texture to model. I've created model and Celestia recognised it, but it's in grey color, not texture is shown, why?
Thanks again for help.

[Johaen]

The issue is probably that the image is not the correct size. Go to http://www.lepp.cornell.edu/~seb/celest ... tro.html#6 and scroll down to the part that says "Cause: The image that's provided is the wrong size". Don't worry, I had the same issue when I made my 1st planet

[Lalla]

Nothing to do, surface remaining grey.

Now I explain you what I want do.

I've found these images:

1) http://www.rc-astro.com/php/displayImage.htm?id=1161
2) http://www.rc-astro.com/php/displayImage.htm?id=1121

and I want use them to:

1) create a flat surface
2) create a sphere and then put on it sun image

I've follow instructions of your link, but...nothing to do... ...flat and sphere objects still remaing grey or white.

For render flat object I used Bryce 5, for sphere a software called easymodel, then I create folders and put inside objects and textures, then I edited a *.dsc, but...I don't understand how declare textures.

1) I need also a ssc file or a dat file?
2) Textures must are 1024*1024?

My OpenGL's 1024.

Celestia is a good program but is a bit complicated...

[jdou]

Take a look at Motherlode to see examples could be helpful
http://www.celestiamotherlode.net/catalog/messiernebulae.php

[selden]

Nothing to do, surface remaining grey.

Now I explain you what I want do.

I've found these images:

1) http://www.rc-astro.com/php/displayImage.htm?id=1161

That one is "easy": a flat picture on a flat model.

2) http://www.rc-astro.com/php/displayImage.htm?id=1121

This one is harder: it has to be projected onto a hemisphere, not wrapped around around a sphere the way Celestia does.

I've follow instructions of your link, but...nothing to do... ...flat and sphere objects still remaing grey or white.

That means Celestia cannot find the image files that the models are specifying.

For render flat object I used Bryce 5, for sphere a software called easymodel, then I create folders and put inside objects and textures, then I edited a *.dsc, but...I don't understand how declare textures.

You must specify the names of the textures in the "material" definition that you create for your model in your 3D modelling program. I don't use Bryce, so I don't know how that is done. It probably is an option in the same menu where you specify an object's color. The names that you would specify would be just "eagle.jpg" and "mysun.jpg". Don't include a directory specification.

You must put the image files into the folder \textures\medres\ associated with your Addon.

1) I need also a ssc file or a dat file?

A DSC file would be used for #1. You'll need to change these values in order to align your model correctly in Celestia.

Code: Select all

Nebula "eagle" {
   Mesh "eagle.3ds"
   Axis     [0.514004 -0.633374 -0.578479]
   Angle 113.027

   RA 18.31638
   Dec -13.8304
   Distance 7000
     Radius 40.5
}

An SSC file would be used for #2.
You would need to define a fake planet with an SMA of 0 and an orbital period of 1e32.

Code: Select all

"MySun" "Sol" {
Mesh "mysun.3ds"
Radius 700000 # big enough to hide Celestia's sun
Emissive true   # to make it seem to glow
EllipticalOrbit { 
    Period 1e32
    SemiMajorAxis 0
    }
}


After you get that working, you can add the correct RotationPeriod, Obliquity, etc.

2) Textures must are 1024*1024?

My OpenGL's 1024.

Yes: your card cannot use model surface textures larger than 1024x1024.

Celestia is a good program but is a bit complicated...

Not once you understand it !

I hope this helps a little.

[Lalla]

Thanks Selden for you help.
Last question, what software can I use for make flat and sphere model instead bryce and easymodel?

[selden]

I use Anim8or, which is freeware.

http://www.anim8or.com/

[Lalla]

Thanks!
I think this is a very good software...
For applying texture in Celestia's way can I use option UV or what?

[selden]

Anim8or's UV option works OK but is a little crude. It should be fine for what you've described so far.

UVMapper and LithUnwrap are freeware UV remappers.

[Lalla]

What program uses ".cms" extension?
Thanks.

[selden]

Only Celestia. It's a simple text description used to generate random asteroidal shapes.