Creating a Planet for Orxonox

This tutorial will show you how to create a planet with procedurale textures for Orxonox.

1st Step

First we have to create an actual mesh for our planet. Most often people use UV-spheres for this purpose, however unsightly texture distortions occur, especially around the poles, because of the UV unwrap. Those distortions can be prevented by using a cube and moving the vertexes so that they lie on the surface of a sphere. That way there are only very minor distortions. Confused yet? Good. I'll show you now how to all that, step by step:

First start Blender and select the pre-created cube and press TAB to enter edit mode and choose all vertexes/edges/faces.
Next press CTRL + E and from the pop-up choose the option Mark seam.
You should end up with some like this:
Next, switch to UV Face Select mode, press U, select Unwrap and distribute the vertexes evenly. In order to spare you the time fiddling about with this, here's a blend file with all steps done until this point.
You should end up with something like this in the UV Editor:
Baking only works on existing images. That means, you have to create an image in (e.g.) gimp with a 2:3 aspect ratio (other aspect ratios work too, but the less distortion the better). A good resolution is 1536x1024. Open the image in the UV Editor under File
You now need to distribute the vertexes evenly so the whole image is used and no space wasted.

2nd Step

Now before we go any further with the model, we'll create the texture and bake it to an image. That way we can later change the model but keep the original UV coordinates and mapping.

Now onto the textures. Press F6 to get to the texture window. Add new adds a texture layer to your model (Make sure there exists a base material in the editor window (F9)).
There are a few procedurale texture algorithms available but most often Musgrave, Clouds and Noise work best. Here you are pretty much free to play around with the settings.
After setting up your algorithms, you need to assing a colour to them. Go to Material buttons (red orb) and click on Texture. Click on the texture you want to alter and click on Map to. Here you can choose the colour which you want to be assigned to the algorithm - just click on the coloured field. Proceed doing this for all your textures. You may want to assign a different colour to the gray background texture too.
In order to get our texture into the game, we need to "bake" it, i.e. render the texture to an image. To do this, press F10 and Bake. In the bake menu, click on Textures and BAKE to bake it.
You'll hopefully end up with something like this in your UV editor
Save the image in the UV editor, you'll need it for the game

3rd Step

In the next step we'll increase the vertexcount of the cube and map it to a sphere.

Press F9 and TAB to get into edit mode. Click on Subdive in order to increase the vertex count, about 1538 vertexes should be enough
Next make sure that your space cursor lies in the origin. If not, just press "SHIFT + C" to reset it.
Click on To Sphere, make sure it's on 100 and press ok.
Now we need to resize the sphere's radius to 1 so that the scaling in-game works properly. Make sure the whole sphere is selected and press S. Scale it to 1.

4th Step

Exporting Meshes is explained properly in this wiki-article: https://www.orxonox.net/wiki/BlenderExport