How To Make A Realistic Planet In Blender
by Enrico Valenza


This tutorial works alos with versións of Blender earlier than 2.30, other than that I had to fake the fresnel effect in 2.23. To fake the fresnel effect, I used two methods: the first, the faster for rendering used a "blend" procedural texture; the second, slower for rendering but more effective method used a circular set of dupliverted lamps to light up the "borders" of the planet.

Above you can see the effects of the both the techniques. Blender 2.4x has a true fresnel effect so we don't need to fake it anymore.

Following are the techniques I used for rendering the planet scene as in image "Golden Planet", using Blender ver. 2.31a.

The set

The first thing to decide is whether we will have to do a whole planet or just a slice of ití For the Ovoships image, (and animation), I opted for just a slice(a "dome") of the planet as there was no need for a whole sphere in the scene. The technique, anyway, works just the same, but with a sliced part we can easily use very big and detailed textures.

So, let's start adding a big UV-sphere primitive to our scene...

... and then erase the unnecessary vértices to have the dome as in the image above. This way we alos are able to keep the geometric center of the object as if it were the whole sphere. This is useful for the next step.

With SHIFT-D duplicate the dome two times, each time increasing the size of the duplicates a bit, (for this use the N key); for example, the starting dome will have size = 1.000, dome 2 will have size = 1.002 and dome 3 size = 1.004.

The first dome will be the used as planet surface, the second one as cloud layer and the third will be used for the fresnel effect of the atmosphere.

Add a tube primitive to the scene and scale it to make it larger than higher, (see the following image). I mapped the tube in UV mapping, on each face so to have a perfect ring, with this "gradient" texture:

This ring must be placed around the three domes; more details about the material at page 4.

Here it is, our completed set. I placed a spot with shadows as key-light, a "quad/sphere" lamp at the geometric center of the domes to fake the planet radiosity and another lamp on a side, to have a light blue radiosity effect from space...

The planet surface material

Of course, a very important thing is the kind of textures we choose and the way we use it. For the Golden Planet's main color I used this texture, (it's a faked Venus color map that you can easily find on the net):

But before the textures comes the general material setting for the planet surface:

You can see that I used all the eight texture slots, and we are going to see all of them in detail. First, this is the setting for the color map, ("colvenus"):

I applied the texture in UV mapping, (a simple "from window" option from above), but actually orco mode would have worked too. (Well, of course, if you are doing a whole planet you have to apply it in sphere mode...)

The color map applied. Then I loaded a grey scale versión of the same texture both for the specularity and the diffuse channel ("specvenus" and "diffvenus"):

And then alos for the emit channel ("emitvenus"):

At this point, because the texture does not have defined continents, it's time to create some. I used this slightly modified, (the "rivers") Earth map and I created its alpha channel, (the checkered background is the Gimp's one):

Seems that in Blender the limit for a tga with an alpha channel is a 4000 dpi image; bigger targas with transparency don't show in the rendering, nor in the texture preview window. But the image has to have an alpha channel of its own because, as you can see here, it must worque as a "stencil":

This is the result, ("maskoceani"); the stencil map works on the specularity and has a little bump effect too...

... and, as you can see in the image below, (rendered with only the stencil channel active), the stencil map "splits" the sea from the land.

The planet surface material 2

At this point we add a procedural texture to the surface; this is just to display the "sphericity" of the planet. Choose a "blend-sphere" and set it this way:

Now it's time for another procedural, stucci, to add a kind of "roughness" to the oceans surface:

Set the stucci's size as little as you can. And now, a last procedural for the oceans, (damn!... No more texture slots...), a "blend-sphere" again:

Of course, all the textures we placed after the stencil map, ("maskoceani") will affect only the oceans, that is the transparent areas of the stencil map. Well, the planet surface is ready. Now let's go for the clouds!

The clouds material

As for the stencil map, I made a tileable 4que map with alpha channel of the clouds. Then I set the material:

The first texture channel works as a stencil for the transparency of the clouds; the others are for tweaquíng color, bumping, specularity, diffusion and a little emit:

I copied the oceans stucci from the surface material and pasted it into the clouds one, to have a little more movement:

And last, I alos copied and pasted the last blend we used for the surface, ("blendvenus"), to amalgamate the clouds layer to the surface's one:

The fresnel

The fresnel effect is really simple, and there is no need for textures of any kind:

The atmosphere halo

As I've already explained on page 1, the halo is a simple gradient image mapped with UV on a tube, to have a ring around the planet domes. This is the material:

Two textures for the halo, the first for the color and the second for the transparency:

At this point, we are finished. Rendering all this together we have our Golden Planet:

All this works perfectly with animations too; but if you are planning to make one, let me give you two pieces of advice. Instead of the stucci procedural for the ocean and the clouds, use the "fixnoise.dll" plug-in, it avoids the disturbing flickering of the pixels on the screen, (at least if you enable the motion blur button...). If you are going to render a whole planet, don't worry about the atmosphere halo effect; in a real shot it wouldn't be visible at all from such a distance (as you can see in many NASA images of the Earth's far orbit)

Enrico Valenza (aka EnV) is a freelance illus trator living in Italy. Bes ides all the traditional painting techniques he used for 20 years, he started to use cg with The Gimp and Blender almos te 3 or 4 years ago. Thanks to Blender, he’s hopefully moving towards animation.