How I make planetary textures - a short tutorial
Posted: 05.12.2007, 22:16
After reading quite a few posts here, I learned quite a bit. Thank all of you for your creative suggestions, and thanks also to the authors of Celestia. As my way of giving back to the community, I decided to write a short tutorial about how I make earth-like planets, out in the barren cosmos. I welcome any suggestions.you might have (especially for how to improve cloud patterns), and will try to answer any questions I get hit with.
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I'm no artist, but I do need good artwork for space-based books, album covers, etc. Since the program knows about extrasolar systems, I can pick one of those, choose a planet, modify the exrtrasolar.ssc file to my specs (using Earth or other data), and then add the textures to the highres directory.
My graphics card can only handle 2k textures. That's good enough for me right now, though later I will probably delve into Virtual Textures (and upgrade the graphics card). I use two programs to create textures:
* PlanetGen V. 4 Beta 4, to create the planet info
* GIMP 2.2 (with DDS and NormalMap add-ons), to edit then into final form.
(Below, I save two of the texture files as a DDS, but you can save them as JPGs instead, although Celestia can't load them as fast - If your card can handle DDS, do it!)
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PlanetGen has a number of settings - read the docs, and play with the settings. It creates two kinds of textures: a relief map, and a climate map. After you get those two files created, do:
To edit the main Celestia background image:
1. Bring up Relief Map
2. Use Filters -> Map -> Bumpmap - set to taste (it's a good idea to read the Docs...)
3. Open as Layer Climate Map
4. Use Layer - Transparency - > Color To Alpha, set black (000000) as the color
5. Use Image -> Merge Visible Layers
6. Save As a DDS file to High-Res directory (or wherever applies) - I use DXT1
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To make the Celestia night-time pic (there's no doubt better ways to do it, but this is a quick and dirty solve):
1. Open Relief map
2. Use Filters -> Decompose (RGB, Decompose to layers, which is the default)
3. The Blue layer should be on top, so you can invert that with:
* Layers -> Colors -> Invert
4. To get a night-time appearance, I simply adjust the brightness/contrast to something that looks decent:
* Layers - Colors - Brightness-Contrast
* I set the brightness to -127, and play with the contrast to get something semi-decent
* This is usually brightness at -127, and contrast at +127
5. Use Image -> Merge visible Layers
6. Save As a DDS file to High-Res directory (or wherever applies)
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If you want white clouds, those are fairly simple. If you want white, purple, blue, and green clouds, it's a bit more complicated (I haven't tried those layers yet, so don't ask me to explain it just now...)
How I do it...
1. Open a blank file (I use 2048x1024)
2. Use Filters -> Render -> Clouds -> Solid Noise
3. You can optionally click on Turbulent
4. You'll want to make sure that you click on tilable, because the patterns need to go from edge to edge
5. Change X and Y to your liking, and keep clicking New Seed until you see what you want (play with it until you're happy with the preview)
6. You will usually want a Detail higher than 1....
7 Click OK when you like what you see - this will generate the clouds pattern
* (If you're gonna change the cloud color, now's the time)
8. Use Layer - Transparency - > Color To Alpha, set black (000000) as the color (unless you changed the white clouds to something else - don't know the specifics in this case)
9. Save the new checkerboarded file as a PNG file, as JPGs can't have transparencies, and DDS files (on this system anyway) suck with transparencies
----
Later on, I'll post some of my planets via link to this thread. I just don't have them online yet, but that will change over the coming weeks. They're far from perfect, but not bad coming from a non-artist, at least in my opinion. I'm sure somebody else can improve this tutorial (hint, hint)....
- Danny
----
I'm no artist, but I do need good artwork for space-based books, album covers, etc. Since the program knows about extrasolar systems, I can pick one of those, choose a planet, modify the exrtrasolar.ssc file to my specs (using Earth or other data), and then add the textures to the highres directory.
My graphics card can only handle 2k textures. That's good enough for me right now, though later I will probably delve into Virtual Textures (and upgrade the graphics card). I use two programs to create textures:
* PlanetGen V. 4 Beta 4, to create the planet info
* GIMP 2.2 (with DDS and NormalMap add-ons), to edit then into final form.
(Below, I save two of the texture files as a DDS, but you can save them as JPGs instead, although Celestia can't load them as fast - If your card can handle DDS, do it!)
----
PlanetGen has a number of settings - read the docs, and play with the settings. It creates two kinds of textures: a relief map, and a climate map. After you get those two files created, do:
To edit the main Celestia background image:
1. Bring up Relief Map
2. Use Filters -> Map -> Bumpmap - set to taste (it's a good idea to read the Docs...)
3. Open as Layer Climate Map
4. Use Layer - Transparency - > Color To Alpha, set black (000000) as the color
5. Use Image -> Merge Visible Layers
6. Save As a DDS file to High-Res directory (or wherever applies) - I use DXT1
----
To make the Celestia night-time pic (there's no doubt better ways to do it, but this is a quick and dirty solve):
1. Open Relief map
2. Use Filters -> Decompose (RGB, Decompose to layers, which is the default)
3. The Blue layer should be on top, so you can invert that with:
* Layers -> Colors -> Invert
4. To get a night-time appearance, I simply adjust the brightness/contrast to something that looks decent:
* Layers - Colors - Brightness-Contrast
* I set the brightness to -127, and play with the contrast to get something semi-decent
* This is usually brightness at -127, and contrast at +127
5. Use Image -> Merge visible Layers
6. Save As a DDS file to High-Res directory (or wherever applies)
----
If you want white clouds, those are fairly simple. If you want white, purple, blue, and green clouds, it's a bit more complicated (I haven't tried those layers yet, so don't ask me to explain it just now...)
How I do it...
1. Open a blank file (I use 2048x1024)
2. Use Filters -> Render -> Clouds -> Solid Noise
3. You can optionally click on Turbulent
4. You'll want to make sure that you click on tilable, because the patterns need to go from edge to edge
5. Change X and Y to your liking, and keep clicking New Seed until you see what you want (play with it until you're happy with the preview)
6. You will usually want a Detail higher than 1....
7 Click OK when you like what you see - this will generate the clouds pattern
* (If you're gonna change the cloud color, now's the time)
8. Use Layer - Transparency - > Color To Alpha, set black (000000) as the color (unless you changed the white clouds to something else - don't know the specifics in this case)
9. Save the new checkerboarded file as a PNG file, as JPGs can't have transparencies, and DDS files (on this system anyway) suck with transparencies
----
Later on, I'll post some of my planets via link to this thread. I just don't have them online yet, but that will change over the coming weeks. They're far from perfect, but not bad coming from a non-artist, at least in my opinion. I'm sure somebody else can improve this tutorial (hint, hint)....
- Danny