The entire workflow:

• Part 1: Download elevation data as an image, preparations (editing)
• Part 2: Generate a terrain from texture (WorldMachine)
• Part 3: Modify the terrain in WorldMachine
• Part 4: Generate the additional textures from the modified terrain in Substance Painter/Substance Designer
• Part 5: Create the scene in Maya/Arnold

Part 3: Modify the terrain in WorldMachine

It’s really good to start with a realistic (true size and height) terrain.
Usually you don’t want to use the whole original terrain (generated from the GeoTiff file), but a small part of it. Than you can modify the terrain with additional procedural generators to get a different or more exciting result (or both 🙂 ).

• First you have to decide the size (in km) and the maximum elevation (in meter).
  Projects Settings -> Render Extends and Normal Build Resolution:
  Set the Width and Height, for example 5 km × 5 km. Keep the resolution low for previews.
  Projects Settings -> General Setup:
  Set the Maximum Elevation. Usually you want to set this value higher than the original (which you used in the simple GeoTiff version). This is not modify the original shape (generated form the GeoTiff texture).
• I recommend you to change the terrain color for less distraction.
  Set Terrain Color… -> Icelandic
• Now you can choose which part you want to see from the original terrain.
  Open the File Input device -> Click Set in Layout…
  Move the whole terrain to find an interesting part.
• You need to blur the terrain a bit. Create a Blur device and connect it.
  
  To get an accurate preview build the network.

There are many ways to create or modify a terrain. Here is one:

• Create a Layout Generator, open it (double click).
• Choose the Polygon tool, draw some points, right click twice to exit the tool.
• Now you can select and move the terrain as you want.
• Select the shape and open the Shape Properties (the pencil like icon).
  Change the maximum Height and play some with the parameters.
  Other useful editing tools are Rotate and Scale (right click on the shape).
  The best part is the Use Breakup feature. Turn it on. Click the Edit button. Lower the Breakup Scale to see the effect.
  

Combine and Erosion:

• Create a Combiner.
• Connect the the File Input and the Layout Generator.
• Open the Combiner and change the Method and the Strength as you like.
• Create a Erosion device (connect the combiner). Play with it. It’ pretty cool.
• Build to see the result:
  

Textures. You have many options to create base textures and masks, this is one simple example:

• I used a Select Height, two Colorizer (one for the Flow map and one for the Deposition map), a Basic Coverage macro (Coverage Library), a Combiner and a Chooser device.
• An Overlay View device to preview the heightfield and the texture together.

Outputs:

• Finally you need some output device: a few Bitmap Output to extract the textures and masks and a Height Output to extract a dispalcement (height) map.
• Before you build the final version set the resolution to 4k or higher if you have a lot of memory :).
• Use the Tiff (16bit) format for masks and for the dispalcement map.
• You can use 8 bit format for the colored textures.

Useful shortcuts:

• F – Lock Preview
• Views -> Open Additional Window
• X – Disconnect Device
• D – Disable Device
• B – Bypass Device

Tips:

• In the Preferences you can change the Graphics Options for better preview.
• At the resolution slider (Project Settings) you find the +1 switch, in some cases that is needed, it’s depending from the target software.
• Turn off the Lighting option in the Basic Coverage macro.
• You can choose how you want to see the data in each device:
  Right click -> Set device display hint

The final terrain:

Cheers, D