Type "Sb" // the Hubble type RA 18.365 // right ascension Dec -30.1643 // declination Dist 86.67e6 // distance from the Sun Radius 21000 // radius AbsMagn -21.5 // absolute magnitude Quat ( -0.9269889 0.2641924 0.03661448 0.2637298 ) // orientation quaternion
}Galaxy "Milky Way" // parent galaxy Type "Open" // type RA 5.78333333 // right ascension Dec 16.1166667 // declination Dist 1230.9 // distance from the Sun Radius 4.68 // radius AbsMagn -3.6 // absolute magnitude CenPow 0.5 // stars concentration parameter Age 760 // age NStars 1500 // number of stars Color (0.86 0.92 1.00) // color of the star-like particle
}Galaxy "Milky Way" // parent galaxy Type "Diffuse" // type RA 04 46 18 // right ascension Dec -16 07 36 // declination Dist 520.3 // distance from the Sun Radius 3.5 // radius AppMagn 5 // apparent magnitude Quat ( -0.3156767 -0.6193562 0.2975453 -0.6543798 ) // orientation quaternion
}
4) Next step is selecting the interstellar dust pattern. Dust is a brown streaks visible on the galaxy's spiral arms. Near the center you can see how they gradually disappears into a yellow "fog" - a spherical bulge of the galaxy. Select the dust like you selected the stars, or use the tool Select -> Color Range. Create the alpha channel and copy selected dust there. Bright areas in the alpha channel must outline the dust in the galaxy, so you may need to invert the image. Here is the example of what you must achieve in the alpha channel (click to enlarge):
5) Create the small version of this texture. It is just a reduced to 128 x 128 copy of the front texture. It is used as "LOD 0" texture if the galaxy is far away, and also for generating the 3D sprite model. Note: Photoshop likes to add a thin gray frame around the image while rescaling. So make sure you have removed it with eraser tool or other method. Look at the small texture example below: its alpha channel have noticeable frame. If not removed, these gray pixels may lead to generating of redundant sprites in the 3D model.
6) Now it's time to create a subsystems texture. Create a new document (image) with the same dimensions as the edited (big) front texture. Then copy RGB image of the front texture into that new document. The subsystems texture is a pattern which is used to generate procedural diffuse nebulae (the red channel), open star clusters (green channel) and the young blue stars (blue channel). So it can easily be made by adjusting the levels/contrast in each of the color channels separately. You also need to erase the galaxy core - there must be no nebulae, star clusters, and blue giants generated. You can use the hand tools Burn and Dodge to enhance star forming regions (in the blue channel) and nebulae (in the red channel). If galaxy image have no very well defined nebulae, you can copy the dust distribution map to the red channel and (nebulae appear near dust clouds). Here is the example of what you must achieve (click to enlarge):
7) Save the files. It is recommended to save the front texture and it's small version into the alpha-PNG format. Note: Photoshop can't save PNG with the alpha channel, so it is better to save the texture in TGA format, and then convert it to PNG using SpaceEngine. It have an option for convert any texture to any supported format with correct saving of the alpha channel. To use it, run SpaceEngine, open the console with [~] key and type there:
SavePNG addons/textures/galaxies/MyGalaxy.tga
where MyGalaxy.tga is a file name of the texture you want to convert. This command loads the texture MyGalaxy.tga and saves it with name MyGalaxy.png to the same folder. There are commands for converting to all other formats available: SaveJPG, SaveDDS, SaveTGA, SavePNG, SaveTIF.
The subsystems texture can be saved in any format, including JPEGá because it does not have an alpha-channel.
8) You can edit the model script and textures while running SpaceEngine, and update the model on-the-fly. To do this, select the galaxy you are editing, switch to the Edit mode (hit the [*] key twice), and press [Ctrl]-[Shift]-[F5]. The model of the galaxy that is currently selected will be updated.
Good photos of galaxies can be taken from the Hubble website. Choose the galaxies which have full coverage in the frame, on images which was taken in the visible light in natural color. It is better to grab photos in TIFF format without compression so there will not be JPEG compression artifacts.[/vc_column_text][/no_accordion_section][/no_accordion][/vc_column][/vc_row]