Visit the original blog post at http://fragileearthstudios.com/2012/09/15/generating-complex-terrains/ for additional information and sample files. Forget what you know about editing terrains. Unlike the terrain editor in Unity that functions like a paint program, World Machine (and programs like it) operate on a procedural level. A World Machine world file is not the terrain, but the steps that creates the terrain. This is the source of both its power and its complexity. This presentation covers the process on how to use World Machine in conjunction with Unity3D to generate realistic looking terrains for your scene.

1. Generating Complex Terrains for Unity3D
Eric Hackathorn
9/10/2012
Terrain by Vincent Ferrand

2. Preparation Download material from
the classroom web site
You should be
done with
this!

3. The World Machine Device
Program Variables
Inputs
World Machine operates Outputs
on a procedural level. A
World Machine world file
is not the terrain, but the
steps that creates the
terrain.
Input Mask
http://world-machine.com/learn.php

4. Overall Device Structure

5. Terrain Generation Overview

6. Perlin
Perlin Noise works by layering the output of
several sets of noise together. These layers are
called octaves. The multiple octaves are
combined together in a variety of ways to
create the final result.

7. Radial Gradient
The Radial Gradient
generator creates
shapes that are all
centered around one
point in space. (Ex:
spherical, gaussian,
diamond, square,
cone.)

8. Combiner
The combiner combines
two separate terrains
into one. There are a
variety of different
methods that can be
used to combine the
terrains -- each will give
a different effect.

9. Layout
A layout generator interacts with the
layout view to provide a home for a set
of shapes you can use to define terrain
shapes, create masks, add roads, and
more.

10. Erosion
The erosion filter simulates the work of thousands or
millions of years of weathering and erosion by rain,
flowing water and mass movement. It is an
exceptionally useful tool to add detail and realism to
human-created terrains. There are a large number of
parameters in the Erosion device and each parameter
can interact with the others to create to a unique
effect.

11. Terrain Height Map

12. Bitmap Generation Overview

13. Select Slope
The slope selector is used to
create a mask that highlights
areas of the terrain that have
a particular slope. The output
will be full strength (white) in
those sloped areas and zero
strength (black) outside of it.

14. Select Convexity
The convexity selector discovers areas of the
input terrain that are either highly exposed
(convex) or recessed (concave). Convex areas
are white (one), while concave areas are black
(zero). Neutral areas that are neither will be
neutral grey. This device can be very useful for
texturing to either to help shadow recessed
cracks in the terrain, or to bring out ridges and
other areas that are highly exposed.

15. Select Height
The height selector is used to
create a mask that highlights
a certain height range of the
input terrain. The output will
be full strength (white) in that
range area and zero strength
(black) outside of it.

16. Probability Filter
The probability filter treats the input map as a
probability density function, and creates a
mask that randomly scatters dots according to
that density function. It is intended to be
useful for object placement maps.

17. Channel Combiner
The channel combiner recombines
three individual height fields into a
bitmap typically using the red, blue,
and green channels.

18. Splat Map
Terrain Distribution Maps
Grass Distribution
Tree Distribution

19. Output File Overview

20. File Types
The file output device saves the fully built The bitmap output allows you to export a
height field to disk. Only the height field bitmap data type to a file. You may export
information is saved -- any color-height to either 8 or 16bit per channel color
mapping applied in World Machine is for formats.
illustration only, and is lost.

21. Import into Unity
Height Map Splat Map Grass Map Tree Map
One small last part…

22. Height Map

23. Scene Setup
The terrain paint tool is The tree placement tool is The grass and detail
expecting four textures for expecting three prefabs for placement tool is
the R, G, B, and Alpha the R, G, and B channels of expecting six grass or
channels of the splat map. the tree distribution map. detail meshes for the R, G,
and B channels of the
grass distribution maps.

24. Terrain Script
Drag the appropriate textures into the splat map, tree distribution, and grass/detail
distribution settings in “Julien’s Terrain Tools” and hit apply.

25. Questions?
Eric Hackathorn
eric@fragileearthstudios.com