{"id":631,"date":"2016-10-30T20:23:46","date_gmt":"2016-10-30T20:23:46","guid":{"rendered":"http:\/\/spaceengine.org\/?page_id=631"},"modified":"2018-11-03T11:48:43","modified_gmt":"2018-11-03T11:48:43","slug":"creating-a-dso","status":"publish","type":"page","link":"https:\/\/spaceengine.org\/manual\/making-addons\/creating-a-dso\/","title":{"rendered":"Creating a DSO"},"content":{"rendered":"

[vc_row row_type=\"row\" use_row_as_full_screen_section=\"no\" type=\"full_width\" text_align=\"left\" box_shadow_on_row=\"no\"][vc_column][no_accordion active_tab=\"1\" background_transparency=\"no\" style=\"boxed_accordion\"][no_accordion_section title=\"Creating a deep space object\" accordion_type=\"accordion_icon\" icon_pack=\"font_elegant\" fe_icon=\"icon_cog\"][vc_column_text]This manual describes how to add a galaxy, star cluster or nebula to SpaceEngine. Before continuing, it is recommended that you read this manual: Introduction<\/a>.<\/p>\n

Galaxies, star clusters and nebulae have a similar format of catalog file. They are stored in the virtual folders *\/catalogs\/galaxies\/<\/span>, *\/catalogs\/clusters\/<\/span> and *\/catalogs\/nebuale\/<\/span>, respectively. To add a new object, create the sc file in the needed subfolder in the addons<\/span> folder, and type the script in it (see below). You can add multiple object scripts to the sc file.<\/p>\n

You can also create a custom 3D model for galaxy or nebula. Otherwise SpaceEngine will use one of the standard models, assigning it to your object based on its type. You can make a custom model and assign it to a specific galaxy\/nebula, or tell SE to assign it procedurally to all galaxies\/nebulae which have a certain type (for example, \"Sa\" galaxies). You can also modify the standard models.<\/p>\n

Note:<\/span> the current version of SpaceEngine does not support procedural generation of galaxies and nebulae, therefore all galaxies\/nebulae uses one of the standard models. If you add new models to the types of galaxies\/nebulae, some fraction of these objects in SpaceEngine will use your models.<\/p>\n

The majority of galaxies in the default SpaceEngine installation are stored in the csv file data\/catalogs\/<\/span>Catalogs0980.pak\/galaxies\/NGC-IC.csv<\/span>. This is the NGC\/IC galaxy catalog with about 10,000 galaxies. Some other galaxies are stored in few sc files in the same system pak file. These default files should not be modified or changed in any way. If you want to update a galaxy, remove it, or add a new one, create your own sc or csv file in the addons\/catalogs\/galaxies\/<\/span> folder. SpaceEngine has scripting options to modify and remove objects from the default catalogs, or to add new ones.<\/p>\n

The csv format for a catalogs is designed to create a large list of objects with similar data. It is more compact and loads faster than sc, but has limits to the types of data which can be specified in it. It is just a table with values separated by commas. The sc format is designed to specify any possible data that SE can use to describe an object. It is a script-like text with 'tags' used to describe an object and its various parameters. First we'll describe the sc file format.<\/p>\n

The galaxy\/cluster\/nebula catalogs<\/h4>\n

Galaxies, star clusters and nebulae have very of catalog file formats. They differ only by location on the disk, main tag name, and a few parameters specific for only some types of object.<\/p>\n

Let's consider you want to create a new galaxy called \"MyGalaxy\". Go to the addons\/catalogs\/galaxies\/<\/span> directory (create it if it does not exist) and create a new text document there. Rename it to mygalaxy.sc<\/span> (the file name doesn't matter, but make sure it doesn't match some existing file, otherwise your file will override<\/a> it). Open it in Notepad and type this code:<\/p>\n

<\/p>\n

\n
Code<\/div>\n

\nGalaxy \"MyGalaxy\"
\n{<\/p>\n

\nType\u00a0\u00a0\u00a0\u00a0\"Sb\"\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ the Hubble type
\nRA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a018.365\u00a0\u00a0\/\/ right ascension
\nDec\u00a0\u00a0\u00a0\u00a0\u00a0-30.1643\u00a0\/\/ declination
\nDist\u00a0\u00a0\u00a0\u00a0\u00a086.67e6\u00a0\/\/ distance from the Sun
\nRadius\u00a0\u00a0\u00a021000\u00a0\u00a0\u00a0\/\/ radius
\nAbsMagn\u00a0-21.5\u00a0\u00a0\u00a0\u00a0\/\/ absolute magnitude
\nQuat\u00a0\u00a0\u00a0\u00a0( -0.9269889 0.2641924 0.03661448 0.2637298 )\u00a0\u00a0\/\/ orientation quaternion\n<\/p>\n

}<\/div>\n<\/div>\n

<\/p>\n

In the galaxy catalog, you can use only these two tags to add a new object or modify the old one:
\nGalaxy \"name\" { }<\/span> - to add\/modify a galaxy,
\nQuasar \"name\" { }<\/span> - to add\/modify a quasar.
\nNote that in the current version of SpaceEngine quasars do not differ from regular galaxies (except designation in the interface).<\/p>\n

To add a new galaxy or modify a galaxy which has already been described in the catalogs, simply define a new object (Galaxy<\/span> or Quasar<\/span>) with the same name in the galaxy script. SpaceEngine will update the old object with the new data (it's also possible to change its type - from
\nGalaxy<\/span> to Quasar<\/span> and back).<\/p>\n

Star clusters can be added\/modified by the same way. Go to the addons\/catalogs\/clusters\/<\/span> directory (create it if it does not exist) and create a new text document there. Rename it to mycluster.sc<\/span> (the file name doesn't matter). Open it in Notepad and type this code:<\/p>\n

<\/p>\n

\n
Code<\/div>\n

\nCluster \"MyCluster\"
\n{<\/p>\n

Galaxy\u00a0\u00a0\"Milky Way\"\u00a0\/\/ parent galaxy
\nType\u00a0\u00a0\u00a0\u00a0\"Open\"\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ type
\nRA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a05.78333333\u00a0\/\/ right ascension
\nDec\u00a0\u00a0\u00a0\u00a0\u00a0\u00a016.1166667\u00a0\/\/ declination
\nDist\u00a0\u00a0\u00a0\u00a0\u00a01230.9\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ distance from the Sun
\nRadius\u00a0\u00a0\u00a04.68\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ radius
\nAbsMagn\u00a0-3.6\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ absolute magnitude
\nCenPow\u00a0\u00a0\u00a00.5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ star concentration parameter
\nAge\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0760\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ age
\nNStars\u00a0\u00a0\u00a01500\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ number of stars
\nColor\u00a0\u00a0\u00a0(0.86 0.92 1.00)\u00a0\u00a0\/\/ color of the star-like particle<\/p>\n

}<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

And nebulas can also be added\/modified by the same way. Go to the addons\/catalogs\/nebulae\/<\/span> directory (create it if it does not exist) and create a new text document there. Rename it to mynebula.sc<\/span> (the file name doesn't matter). Open it in Notepad and type this code:<\/p>\n

<\/p>\n

\n
Code<\/div>\n

\nNebula \"MyNebula\"
\n{<\/p>\n

\nGalaxy\u00a0\u00a0\"Milky Way\"\u00a0\/\/ parent galaxy
\nType\u00a0\u00a0\u00a0\u00a0\"Diffuse\"\u00a0\u00a0\u00a0\/\/ type
\nRA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a004 46 18\u00a0\u00a0\u00a0\/\/ right ascension
\nDec\u00a0\u00a0\u00a0\u00a0\u00a0-16 07 36\u00a0\u00a0\u00a0\/\/ declination
\nDist\u00a0\u00a0\u00a0\u00a0\u00a0520.3\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ distance from the Sun
\nRadius\u00a0\u00a0\u00a03.5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ radius
\nAppMagn\u00a0\u00a05\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ apparent magnitude
\nQuat\u00a0\u00a0\u00a0\u00a0( -0.3156767 -0.6193562 0.2975453 -0.6543798 )\u00a0\u00a0\/\/ orientation quaternion\n<\/p>\n

}
\n<\/div>\n<\/div>\n

<\/p>\n

You can also remove the previously defined galaxy\/quasar\/cluster\/nebula (i.e. object defined in some older catalog files). Use this parameter in the corresponding sc file (i.e. in the galaxy catalog to remove a galaxy, and so on):
\nRemove \"name\"<\/span> - delete a previously defined object.<\/p>\n

The galaxy\/cluster\/nebula script details<\/h4>\n

Here we will describe all the parameters which can be used in scripts for galaxies, star clusters and nebulae. They are very similar, though some parameters are allowed only for certain types of object. Also keep in mind that you must describe a galaxy in a galaxy catalog, it is not allowed in the nebula or star cluster catalog. And so on for nebulas and star clusters. This has been noted in the Introduction to SE scripts<\/a>:<\/p>\n

Galaxy catalogs *\/catalogs\/galaxies\/*.sc<\/span> can have only Galaxy<\/span> and Quasar<\/span> tags;
\nStar cluster catalogs *\/catalogs\/clusters\/*.sc<\/span> can have only Cluster<\/span> tags;
\nNebula catalogs *\/catalogs\/nebuale\/*.sc<\/span> can have only Nebula<\/span> tags.<\/p>\n

Parameters, common for all catalogs<\/h5>\n

RA<\/span> - right ascension in hours, in decimal format or formatted as HH MM SS.SSS
\nDec<\/span> - declination in degrees, in decimal format or formatted as DD MM SS.SSS
\nDist<\/span> - distance from the Sun in parsecs.
\nThe parameters RA, Dec<\/span> and Dist<\/span> can be adjusted in SE in the Edit mode (see below).<\/p>\n

Yaw, Pitch, Roll<\/span> - the Euler angles of orientation of the object, or
\nAxis<\/span> - the orientation of the object in the axis-angle format, or
\nQuat<\/span> - the orientation quaternion of the object.
\nThe orientation parameters can be adjusted in SE in Edit mode (see below). If they are not specified, they are generated procedurally.<\/p>\n

Lum, Luminosity<\/span> - luminosity of the object in units of Sun's luminosity, or
\nAppMagn<\/span> - apparent (optical) magnitude of the object, or
\nAbsMagn<\/span> - absolute (optical) magnitude of the object.<\/p>\n

Radius<\/span> - radius of the object in parsecs.<\/p>\n

Type<\/span> - the morphological type of the object.
\nIn the galaxy catalog it is the Hubble morphological type<\/a> of a galaxy. Allowed types are:
\n\"E0\", \"E1\", \"E2\", \"E3\", \"E4\", \"E5\", \"E6\", \"E7\"<\/span> - elliptical galaxies;
\n\"S0\"<\/span> - lenticular galaxies;
\n\"Sa\", \"Sb\", \"Sc\", \"Sd\"<\/span> - spiral galaxies;
\n\"SBa\", \"SBb\", \"SBc\", \"SBd\"<\/span> - barred spiral galaxies;
\n\"Irr\"<\/span> - irregular galaxies.
\nIn the nebula catalog, allowed types are:
\n\"Diffuse\"<\/span> - diffuse nebula;
\n\"Planetary\"<\/span> - planetary nebula;
\n\"SNR\"<\/span> - supernova remnant.
\nIn the star cluster catalog, allowed types are:
\n\"Globular\"<\/span> - globular cluster;
\n\"Open\"<\/span> - open cluster;
\n\"Kern\"<\/span> - the galactic center cluster (special type, used to represent the galaxy center);
\n\"Part\"<\/span> - part of the galaxy (special type with no stars, used to represent a star clouds like M 24 - the Sagittarius Star Cloud).<\/p>\n

Parameters, used only in the galaxy catalog<\/h5>\n

ModelBright<\/span> - the overall brightness of the galaxy 3D model. Default value is 1.<\/p>\n

SolFade true<\/span> - if specified, generation of procedural objects (stars, star clusters and nebulae) near the Sun will be suppressed. So while looking from the Solar system, there are no visible procedural objects brighter than magnitude 8.1. This is done to prevent change of appearance of real constellations while looking look from the Solar system. The limiting magnitudes for this can be adjusted by the parameters StarMaxAppMagn<\/span>, ClusterMaxAppMagn<\/span> and NebulaMaxAppMagn<\/span> in the config\/main-user.cfg<\/span> file.<\/p>\n

Parameters, used only in the star cluster catalog<\/h5>\n

Galaxy<\/span> - name of the galaxy to which this star cluster belongs. Example: Galaxy \"Milky Way\"<\/span>. This galaxy must exist in SE.<\/p>\n

Age<\/span> - age of the star cluster in millions of years. Affects the generation of procedural stars (younger clusters have more blue stars, older ones have more red giants).<\/p>\n

CenPow<\/span> - the parameter which defines the amount of \"clustering\" of stars in the center of the cluster. Larger value (>1) makes more concentrated clusters, lower value (<1) makes more fuzzy clusters.<\/p>\n

NStars<\/span> - number of stars in cluster, allowed only for open clusters. To disable procedural stars, specify zero: NStars 0<\/span> (used for Pleiades and other clusters which already have a stars in the star catalog). While generating an open cluster model, SpaceEngine sums up the luminosity of generated stars and stops generation when this sum reaches the luminosity of the cluster. So the actual number of stars may be lower than specified by NStars<\/span>.<\/p>\n

Color<\/span> - the RGB vector of the color of the particle that is rendered instead of the cluster model when camera is far away. To disable this particle, set it to black: Color ( 0 0 0 )<\/span> (useful for large or very close clusters). If not specified, will be generated procedurally.<\/p>\n

Parameters, used only in the nebula catalog<\/h5>\n

Galaxy<\/span> - name of the galaxy to which this nebula belongs. Example: Galaxy \"Milky Way\"<\/span>. This galaxy must exist in SE.<\/p>\n

Using the Edit mode<\/h4>\n

The coordinates, orientation and size of the object can be adjusted in SpaceEngine using the Edit mode. To enter the Edit mode, press the [*] button twice. The prompt table will appear in the bottom left of the screen. Using the keystrokes listed in it, you can adjust the parameters of the selected object. The values of RA, Dec, distance, radius and orientation (Axis and Quat) are displayed in the object's information table at the top left side of the screen (don't forgot to switch distance unit to parsecs in the Player settings menu).<\/p>\n

To accurately adjust the visual position and orientation of the object with respect to real stars (using actual photos from telescopes as reference), do the adjusting while looking from the Solar System. Go to the Sun, center the camera view on the object, and use a telescope (Shift + Left mouse drag) to zoom in on it.<\/p>\n

Note: changes are not saved to the script file<\/span>. You must type them manually.<\/p>\n

The csv format for a galaxy catalog<\/h4>\n

SpaceEngine supports the csv (\"Comma-Separated Values\") format for massive star and galaxy catalogs. It is a plain text format with one galaxy described per line, with values separated with commas. The default SpaceEngine installation has one csv galaxy catalog - data\/catalogs\/<\/span>Catalogs0980.pak\/galaxies\/NGC-IC.csv<\/span>, which has 10,896 galaxies, and a size (unpacked) of only 1.3 MB. The csv format is more compact than sc, but has some limitations:
\n1) Only galaxies can be described, quasars are not allowed.
\n2) Only these parameters are allowed: Name, Type, RA, Dec, Dist, AbsMagn, Radius, Quat.<\/p>\n

The file format is simple: the first line is a header with the names of the parameters (separated by commas), the remaining lines are galaxies with their data - values of corresponding parameters (also separated by commas). Here is an example of the first 4 lines of the NGC-IC.csv<\/span> file:<\/p>\n

<\/p>\n

\n
Code<\/div>\n
Name,Type,RA,Dec,Dist,AbsMagn,Radius,Quat.w,Quat.x,Quat.y,Quat.z
\nNGC 1077-2\/NGC 1077B\/MCG 7-6-68\/ZWG 539.95,SBb,2.76720007,40.093299,171388274,-19.07,12463.208,0.840432,0.534431,0.0164455,0.088246
\nNGC 1000\/MCG 7-6-48\/ZWG 539.67\/NPM1G +41.78,E0,2.64690011,41.4603005,140145941,-20.13,14269.0703,0.761034,0.552704,-0.274793,-0.199585
\nIC 275-1\/5ZW309,E0,3.01530009,44.3503005,132235717,-18.31,5770.17432,0.760357,0.523453,-0.316721,-0.218042<\/div>\n<\/div>\n

<\/p>\n

Note that the galaxy name and its Hubble type are not enclosed in quotes. Missing data for some parameters is allowed: just leave these parameters blank, but commas separating them is still necessary (like this: ,,).<\/p>\n

The csv catalogs have a priority over sc catalogs, i.e. they are loaded first. But then the star solver takes the file\/pak modification date to perform star data merging or updating. The config-file parameter CsvLogLevel<\/span> in the config\/main-user.cfg<\/span> file controls the star solver's logging level for all the csv files.<\/p>\n

Creating a custom 3D model for a galaxy or nebula<\/h4>\n

The current version of SpaceEngine (0.9.8.0) uses sprites to render 3D models of galaxies and nebulae. They are very similar in format, thus their scripts are also very similar. There are many methods of creating models in SE, but they are all focussed on creating a 3D distribution of sprites with various sizes and colors. The user can control its shape and color by providing textures (image files) and specifying how to use them to create a 3D sprite model. Spiral galaxies can also use high-resolution disk textures to enhance the rendering quality when the galaxy is observed from the top. The methods provided by SE are:<\/p>\n