Making a World

A challenging task for the illustrator is the construction of a planet seen from orbit, especially an earth-like world.

As you can see, a pure reproduction may not be as interesting as an artistically selective one - for instance, a pure reproduction will be largely obscured by clouds. However, whether or not you are striving for complete realism or artistically credible realism, many of the same techniques can be applied.

Every world needs

• Oceans
• Continents
• Land variation
• Mountains and valleys
• Clouds
• Polar caps

To appear realistic

• Oceans must glare from the sun - continents must not
• Clouds should cast shadows, generally to a limited degree, but dependent on your artistic sense
• The map must be seamless
• Relief and atmospheric thickness must be kept minimal - compared to the size of a planet, the height of mountains and the thickness of atmosphere are almost inconsiderable.

The world above is intended to represent the planet Cocteau, from my novel Source.

It consists of the following maps (note that the maps are vertically oriented with east at the top and north to the left)...

Color Map	Bump Map	Reflect, Shininess and Specularity Map

The key map is the color map. The others are derived directly from it.

The color map was constructed with the help of the Corel PhotoPaint software. The product, which is very reasonable in price, offers some special fills - specifically "Satellite Photography" - that can be used to create a synthetic planetary surface and clouds.

What is especially critical is making sure that the edges map properly.

Mismatched Edges

Ideally, all four edges should match, but keep in mind that when mapped to a sphere, the material around the poles can become highly distorted. The procedure is to first create the color map and then to create an image four times that size, where you can align the edges and paint them.

Do not flip the images - the bottom of one image must connect to the top of the other, and the left to the right.

Note the polar ice caps. While physiographically correct, these also serve to block the distortion which would otherwise be observed at the poles.

Pole Distortion from Spherically Wrapping A Rectangle

Pole Distortion hidden under polar caps

Creating the bump map correctly requires you to keep in mind that the edges of the continents are at sea level. Thus, a good start is to fill the oceans with the color of the shore. Then depending on whether or not you have brighter high points or darker high points, you may need to invert the non polar regions. Finally, greyscale the result.

The next point to keep in mind is that the oceans alone must show reflective behavior. So a map with white oceans and black continents needs to be created. In PhotoPaint, changing the Mode to Black and White (1 bit) using the line art conversion will create just such an image in a single step.

Finally, a similar fill used as a transparency map can create clouds. The "Samples 9 - Eruption" fill can be used for this purpose.

Cloud Map

In Carrara, to be fully effective, this map must be used both as the color and the transparency map.

The easiest way to make the atmosphere is to duplicate the world, make it a fraction larger in all dimensions, and then apply the appropriate shader to the shell.

If using Carrara, make sure to have the renderer allow light through transparency, or the atmosphere will prevent the world from being illuminated.

Conclusion

Creating a world can be a complex task, requiring hours of work. However, careful preparation and the appropriate tools can streamline the process.