Today I am going to look to the stars for inspiration. Space scenes come with their own set of technical challenges. First, let’s plan our scene. When planning a scene, I like to base it on things I know I can make, and add in a few other things that may prove challenging. So, what kinds of things are in space? Stars, planets, moons, nebulae…..and not much else. I already know I don’t want the planet to be Earth. We have all scene Earth from space. Let’s make a new planet! I will use the Gimp to make the surface map. However, a planet texture has to be spherically mapped, so a 2D map won’t cut it. I have a plan, but I will get to that later. Another important decision we have to make is one that most people forget. What kind of art style am I looking for? Realistic…stylized…sci-fi? This is important to keep in mind, especially when creating all the textures yourself. A cartoony planet would clash against a realistic starry sky. I am going to strive for realism, but it may end up looking sci-fi.
We need to start with the most important thing: stars. Just like a planet texture, stars need to be wrapped around the scene spherically. There are two ways to make the stars. We could use an image map like this one…
The benefit of using a picture like this is that you can get more realistic stars. This is a photograph made by NASA. The downside is, you will never find a picture with a high enough resolution. This picture looks big, but when wrapped around the scene, a fraction of it will fill the scene and appear stretched.
The resolution you would require for this to work would be way to big to use. It would also consume RAM like crazy. Instead, we need to use a procedural texture for the stars. That is, a texture based on modules and calculations. A fractal is a great example of a procedural image. It’s an extremely complex image represented by a relatively small formula. Art of Illusion has a procedural texture editor. It ended up being a lot more complicated than I thought it would be.
This may look crazy to you. Allow me to explain what’s going on here. I have labeled the top four sections. The basic star pattern is made by sending the output of a cell module into a colour module. The linear module is just used to scale the pattern. With a few tweaks to those three modules, I can create a variety of star patterns. In this case, I have created four, different star patterns and added them all up to create a single texture. There is a group of six modules at the bottom that I have used to create very distant stars. Here’s what it looks like:
You can’t really see the coloured stars in the image above, but you’re not really supposed to. They’re not turned on. I figured I might need them later. In any case, the texture is completely customizable, so I may alter it later if I wish.
With the stars completed. we need to make the planet. I’ve never made a planet texture from scratch.
I was originally going to make the texture in in the Gimp. My plan was to make it seamless and tile it 3 x 4. There is a program out there called “HDRshop” that could take my image an turn it into a spherical map. After playing with the Gimp for a while, without having any luck, I decided to choose a different method. I decided to use the procedural texture editor to create a planet texture. If you’re striving for realism, a procedural texture can be extremely complicated. Imagine the star texture above, only ten time more complicated. Hours of tweaking an testing went into this, so I hope it will look good in the final scene. Have a look at this:
This gives me a headache, and I’m the one who made it. I had a lot of fun making this. It’s all about observing and adjusting. This was a result of three hours of small tweaks and improvements. I’m not going to bother explaining how I created this. Frankly, I surprised myself with this sophisticated texture. So how does it look?
There are separate modules that control the general shape of the land and the micro detail on the land. The texture will automatically generate mountains ranges, ice caps, equatorial deserts, and shorelines. Since it is procedural, I can modify the shape and colour of the land to easily make knew planets. The work isn’t done, however. We still need to add clouds and atmosphere.
The blue outline of the Earth is the atmosphere
Since my texture is complicated enough, I am going create a new texture for the clouds. Clouds should be relatively simple. The atmosphere will be a slightly larger sphere around the planet that has a dense blue material. I have also slightly changed the colour of the land and water to be more realistic.
The planet, the clouds, and the atmosphere are all different objects. That will make it possible to rotate the clouds independently of the planet surface. I don’t plan on animating this scene, but it’s good practice to consider everything when making a new scene. Maybe I will need an animated planet in the future. You never know.
Just to give you an idea of how scalable procedural textures are, here is the zoomed in version of the planet with the clouds removed:
As you can see, procedural textures are capable of almost infinite detail. This allows a planet zoom to be created with very few assets. Anyway, I have decided to add rings to our planet. Since space is mostly empty, boring stuff, I figured I should add whatever I can to make the scene interesting.
The there are 700 physical objects in the ring. There are three sizes of asteroids, and they all have a very basic texture on them. If you look closely, you may see the dust in the ring as well. This is a just a torus with a simple material applied. It took a little while to get it looking right, but I think it looks great. I forgot to reapply the clouds, but to be honest, I didn’t really like how they looked anyway. I will probably end up remaking that texture.
Ok, here it is. I made a new cloud texture, which looks a lot better than before. I could add more stuff, like comets and meteors, but I’ve already spend a week on this, so I will just let it be.
2.9kb – That is the size file size of all the textures combine. That’s just another perk of procedural textures.
AOI File: Space.zip