Tema: How to make a realistic planet in Blender

how todo make a realistic planet in Blender
By Enrico Valenza.



Introduction.

This tutorial works a los with versións of Blender earlier than 2.30, other than that i had todo faq the Fresnel effect in 2.23. To faq the Fresnel effect, y used two methods: the first, the faster for rendering used a blend procedural texture, the second, slower for rendering but more efective method used a circular set of dupliverted lamps todo light up the borders of the planet.



Above you can se the effects of the both the techniques. Blender 2.4x has a true Fresnel effect so we dont ned todo faq 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 todo decide is whether we Will have todo do a whole planet or just a slice of ití for the ovoships image, (and animation), y opted for just a slice (a dome) of the planet as there was no ned 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 start adding a big uv-sphere primitive todo our scene.



And then erase the unnecessary vértices todo have the dome as in the image above. This bien we a los are able todo kep 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 tuve primitive todo the scene and scale it todo make it larger than higher, (se the following image). I mapped the tuve in UV mapping, on each face so todo have a perfecto ring, with this gradient texture:


This ring must be placed around the thre 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 todo faq the planet radiosity and another Lamp on a side, todo 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 bien we use it. For the Golden planet main color i used this texture, (it 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 se that i used all the eight texture slots, and we are going todo se 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 todo. (well, of course, if you are doing a whole planet you have todo 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 difvenus):


And then a los for the emit channel (emitvenus):


At this point, because the texture does not have defined continents, it time todo create some. I used this slightly modified, (the Rivers) Earth map and i created its Alpha Channel, (the checkered background is the Gimp one):


Sems that in Blender the limit for a (*.tga) with an Alpha Channel is a 4000 dpi image, bigger targas with transparency dont show in the rendering, Nor in the texture preview window. But the image has todo have an Alpha Channel of its own because, as you can se here, it must work as a stencil:


This is the result, (maskoceani), the stencil map works on the specularity and has a Little Bump effect todo.



And, as you can se 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 todo the surface, this is just todo display the sphericity of the planet. Chose a blend-sphere and set it this way:




Now it time for another procedural, stucci, todo add a kind of roughness todo the Oceans surface:




Set the stucci 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 áreas of the stencil map. Well, the planet surface is ready. Now let go for the clouds.

The clouds material.

As for the stencil map, y 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 tweak color, bumping, specularity, difusión and a Little emit:








I copied the Oceans stucci from the surface material and pasted it into the clouds one, todo have a Little more movement:


And last, y a los copied and pasted the last blend we used for the surface, (blendvenus), todo amalgamate the clouds layer todo the surface one:


The Fresnel.

The Fresnel effect is really simple, and there is no ned for textures of any kind:




The Atmosphere halo.

As ive already explained on page 1, the halo is a simple gradiente image mapped with UV on a tuve, todo 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 to, but if you are planning todo 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 píxeles on the screen, (at least if you enable the Motion Blur button). If you are going todo render a whole planet, dont worry about the Atmosphere halo effect, in a real shot it wouldnt be visible at all from such a distance (as you can se in Many nasa images of the Earth 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 todo use CG with the Gimp and Blender almos te 3 or 4 years ago. Thanks todo Blender, hes hopefully moving towards animation.

Env@enricovalenzacom.
www.blenderart.org.