Earth%20Tutorial.pdf

Second Edition

Building Earth in Blender

This tutorial demonstrates how a very realistic Earth may be built and rendered using

the Blender software. Weʼll learn how to

• build and render a photographic-style Earth which may be viewed from reasonably

close distances

• build and render a moon-lit Earth which may be viewed from reasonably close

distances

• build and render a “Blue Marble”-style Earth which may be viewed from very close

distances

I know there are already a lot of Earth tutorials out there - but none of them showed

me how to get quite the effect that I wanted. In addition (and this was frustrating to me), I

found that some of them did not fully explain how to achieve the perfect example renders

they sported. Hopefully, in this tutorial, you will learn how to achieve a nearly exact copy

of my example renders, pixel for pixel!

All of the textures used in these models are free. They come from NASAʼs Visible

Earth project. These are no-nonsense, high resolution textures.

In this tutorial, Iʼm assuming that you know the basics of the Blender software; how-

ever, Iʼm also assuming that youʼve never built a 3D planet before. Are you ready to get

to work? Weʼll start on page 3.

* * *

Part I

Hereʼs an overview of how weʼre going to build our Earth

model: our planet will consist of ive icospheres. The irst ico-

sphere will be the land surface, the next sphere will be the cloud

layer, the third sphere will be the cloud shadow-casting layer, the

fourth sphere will be the atmosphere fresnel effect, and the last

sphere will be the glow of the atmosphere. Weʼll download and

apply some spherical maps to the spheres, and use the node edi-

tor to give the inal touches.

The irst step is to download the maps weʼll be needing.

Weʼll be using four textures for our irst model. Two of them I

edited myself with the aid of Photoshop, so weʼll be download-

ing those from my own website.

With one exception, all of the maps I used in this project

came from this collection:

http://visibleearth.nasa.gov/view_set.php?categoryId=2363

&p=1

Iʼll now give some direct links. The topography map, which

weʼll use to give Earthʼs mountain ranges a bit of a boost, came

from this page (I used the “5400 x 2700 JPEG (645KB)” map):

http://visibleearth.nasa.gov/view_rec.php?id=8391

Next, weʼll need the clouds map, which can be found at this

page (I used the “8192 x 4096 TIFF (34.2MB)” map):

http://visibleearth.nasa.gov/view_rec.php?id=2432

Finally, weʼll download two maps from my own website.

Both maps originally came from the Visible Earth project, but I

modiied them in Photoshop to get the effects I wanted. For the

irst map, I made use of the “replace color” tool in Photoshop

to edit the land and water colors; for the second map, I simply

down-sized a much larger map.

http://web.olp.net/wildernesslodge/land_ocean_ice_

8192%20(modiied).tif

http://web.olp.net/wildernesslodge/world.watermask.(8192%

20modiied).png

The land map is a variation of the Visible Earth land map

found at this link (I used the “8192 x 4096 TIFF (31MB)” map):

http://visibleearth.nasa.gov/view_rec.php?id=2430

The mask (black and white) map is a scaled-down copy of

the “world.watermask.21600x10800.png” map found at this

directory:

http://mirrors.arsc.edu/nasa/landmask/

Youʼll want to check the copyrights and terms of use of

these maps. I provide the necessary credits for all the maps at the

end of this tutorial.

Now that weʼve got the maps, letʼs make a directory in

which to store the maps. Make a new Blender ile and place it

in the same directory as the maps (this will make linking to the

maps a little easier). Letʼs move to the next step: building the

planet model.

* * *

Open the Blender project and delete everything but the cam-

era. Press ʻnʼ key to open the Transform Properties, and give the

camera these settings:

LocX: 0

LocY: -39.07

LocZ: 0

RotX: 90

RotY: 0

RotZ: 0

Move the camera to layer 11 (press alt + 1 to enter). Weʼll

be using the bottom row of layers (11-20) for our cameras and

lamps. For now, weʼll want to show layers 1-4 as well as layer

11, in the 3D Viewport. Give the camera a Clipping End value of

5000.

Add an empty to layer one, give it a size of 10, and center

it at the origin (the center of the 3D space). Weʼll be using this

empty to animate/control our planet.

Now itʼs time for the planet itself. In layer 1, add in an ico-

sphere of subdivision 4 and radius 12. Make sure the sphere is

centered at the origin. Set it smooth, and give it a level 2 subsurf.

This will be the land surface sphere.

Duplicate the icosphere, and set the scale x, y, and z of the

new sphere to 1.002. Move the sphere to layer 2. This will be our

cloud layer.

Still in layer 2, duplicate the cloud sphere, and set the scale

x, y, and z of the new sphere to 1.003. Move the sphere to layer

3 - this will be our atmosphere fresnel sphere. Finally, duplicate

that sphere, set the scale x, y, and z of the new sphere to 1.008,

and move the sphere to layer 4. This will be the atmosphere

glow sphere.

Weʼll make our cloud shadow-casting layer a little later.

Parent the three outer spheres to the land surface sphere, and

parent the land surface sphere to the empty. Go ahead and give

the empty a RotX of -23.44 (the actual tilt of the Earthʼs axis).

From now on, we can rotate the Earth about its local z axis (by

rotating the land surface sphere) to simulate the planetʼs spin, or

about the global z axis (by animating the empty) to simulate its

orbit position. I used a RotZ (global) of -100 on the empty for

my western hemisphere render (as seen on page 1).

Since the Earth has been tilted on its axis, we need to tilt

the camera next, so we wonʼt get a “crooked” render of Earth.

I gave the camera a RotY of 15.437. While weʼre at it, letʼs add

the sun lamps for our planet. Add a sun lamp into layers 1, 2, and

4 (yes, the same object can be in more than one layer at a time!).

Use a rotation X of 90, a RotY of 0, and a RotZ of 47.317. Give

the lamp an energy of 1.3, with a distance of 5000. Turn on the

lampʼs Layer button. Make sure Ray Shadows are enabled.

Duplicate the lamp, and move the new lamp to layer 3. We

need two separate lamps because of the way weʼll split the lay-

ers using nodes. You can constrain the second lamp to copy the

rotation of the irst lamp, to avoid any confusion. Weʼve inished

building our model; now itʼs time to give it some textures.

* * *

Weʼll start with the ground sphere. Add a new material, and

name it appropriately. Give the material a color of

R .122

G .145

B .200

Set the specular color to

R .791

G .821

B .889

For the shaders, use a Minnaert diffuse shader with a Relec-

tion value of .6 and a Dark value of .325, with a Blinn specular

shader with these values:

Spec: 1

Hard: 50

Refr: 2.7

Turn the “TraShad” button on (this is important when it

comes to the shadows from the clouds).

We need three textures for our ground sphere - the ground

map, the topo map, and the mask map.

Add an image texture to the ground sphere, and load the

ground map. Give it a ilter size of .1, and turn on the Min but-

ton. Weʼll do this for every image texture in our Earth models

from now on; it will allow us to render the textures with maxi-

mum detail, yet without getting an overly sharp image. We wonʼt

be using the imageʼs alpha channel - I found this produced some

distracting outlines on the edges of the land masses. Under the

Map Input tab, choose the Spherical mapping option. This will

map the image correctly onto our sphere.

Add a second image texture to the ground sphere, and load

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