Frequently asked question
Questions les plus fréquemment posées
1. What is a dds file ?
It's a file encoded in an algorithm owned by Nvidia, which only could be read, until recently, by graphics boards from the factories of the firm itself. Nevertheless, with brand-new graphics boards from ATI, OpenGL 1.3 (needed for last releases) is supported, hence permit to use the lastest functions.
Major advantage: one can use textures with very high resolutions (until 16k, according to the memory amount in the graphic board) without effect of jerk.
There is a
that let to open these files under Photoshop, as well as edit them. Moreover, you will be able to create yourself these textures from png or tiff pictures (however, be careful with the required memory...), and thus to benefit from the speed offered by this format. Because if this format isn't lossless quality as png is, it use much less memory !
2. What is a ssc file ?
It's a file holding the main informations for one ore more Celestia objects. It include the satellites' names, planets, gravitational datas, etc. It can be edited with notepad, and if you want to progress with Celestia, you'll have to understand how to edit it.
It is meant to be placed in "data" directory (check the main Celestia directory), or still better, at the root directory specialy made in the "extra" directory. To have a look of how it does work, check
3. What is a dsc file ?
It's more or less the same ideas as a ssc file, but applying to galaxies. Theses datas are written in a different way that ssc ones, but as for a ssc file, you can edit dsc files using notepad.
4. What is a 3ds file ?
For what I know at this time, it's a 3D file. It can be opened by any program managing this kind of file, like
(free software), to see to what the objects looks like.
I don't have any idea of how to make them, I still miss the needed knowledge. :-(.
It is meant to be putted in "Models" directory, and the command you have to write into ssc files is placed under "Mesh" section.
Another kind of 3D file, named cms, is only used by Celestia.
5. What is a "location" ?
It's a position that could be displayed on an object (generally speaking, a planet). Showing capitals on the Earth, the land on Mars of Pathfinder, the land on Moon of Apollo 11, etc.
They are joined together in files ssc, themselves categorized according to planet. It is just needed to put these files in the repertory "Extra" of Celestia, but in my research of the pure rationalization; -) I've created a directory named "Locations" inside the directory "Extra".
To display the locations in Celestia, it's pretty easy: look for the key "&" (shift+6, according to the keyboard). You can access a lot of complementary options in "Locations" menu, like change the filter, choose a minimum size to display (related to demographic density), and so on.
6. What is an overlay texture ?
That's a weird option : it allows to superpose a texture on the original texture.
One could display, i.e., continental drift on Earth (or elsewhere), display colours related to elevation, and so on.
The way to display them is the OverlayTexture instruction, a command allowing the texture superposing, only in a AltSurface code (Alternates maps) :
AltSurface "Ocean temperature" "Sol/Earth"
Texture "Earth16k (realistic).dds"
Color [ 0.85 0.85 1.0 ]
SpecularColor [ 0.5 0.5 0.55 ]
7. What is emule ?
It's a peer-to-peer software, that's to say a program to exchange freely every kind of datas.
Method initiated with Napster, which was centered on audio files exchange, it largely overflowed and today, all files in numerical format are shared.
Nice, but for what is that used here? All. The files which I propose in download are dependent on my band-width. I transmit them at only to one person at the same time, and the request is rather consequent.
The main advantage, using P2P (abbreviation), is that I'm not alone to upload the requested file; when someone else has downloaded the file, he shares in the same way and help me to accelerate the download time for futur requests. It's quicker and more reliable, in so far as everyone plays the game and keeps a few times what he downloaded.
Therefore thank you to keep them a few time in share, so that framework has chance to keep on.
To install the software, two adresses : the
, and the one for his best mod,
, including a lot of nice supplementary options (I use this one). Both are free. Welcome into free sharing ! ;-)
To find more informations or tips about emule, got to
. And to get rid of that damn low-id, which prevent full speed download (as you get less clients) go right
Lastly, you will find in the files proposed an emule indicator, a small icon, to show the file is available via emule. It looks like this:
8. What is a NormalMap texture ?
On the contrary to its predecessor, the BumpMap, it indincate the elevation needed for a texture. In such way, you'll feel the montains height, you'll see the chasm profoundness, etc. This is an elaborate effect, very eye candy, it'll be hard to accept you don't have used it in Celestia before.
The use is pretty easy; you add the following row into a solarsys.ssc section (or in any alternate file) :
That's all folk, the result is outstanding !