Creating a terrain

From Rigs Of Rods

This page describes how to create a terrain from scratch using Terragen 0.9

First, before we begin: You need a registered version of Terragen to make this tutorial.

Find or generate a 1025x1025 terrain. The best terrains are made with real DEM (digital elevation map) of real terrain. The problems with real-world DEM are:

• they are rarely precise enough for RoR (that requires 3 meters horizontal resolution DEM). The only sub-10m DEM I know of is the DEM of Saint Helens volcano. What is interesting in high-resolution DEMS is that you will find that major roads levelling is visible in it, and will help you to lay roads in mountains.
• a real-world 3km x 3km terrain features few interesting features (you usually want several valleys and peaks, and they generally do not fit in 3km.

There is an easy solution for both these problems: scale down the terrain, for example scale a 10km x 10km 10m DEM to a 3km x 3km 3m DEM. It is not realistic, but it won't be visible too much because of the fractal nature of mountains.

So you load your terrain in Terragen. In the landscape window, click "size" and set: -Terrain grid points: 1025x1025 (if its not already) -Landscape area: 3000x3000 meters

Still in the landscape window, click "modify": you will see the "set height range" setting. If your terrain is a scaled-down real-world DEM, it may be a little too flat, and you want probably more height range. It depends on the nature of the terrain, but between 250 and 500 meters of range makes a fun-yet-realistic terrain. So set the range from Zero to the height you chosen, then click on "set height range". Remember the height you set there (write it down on a paper), you'll need this value for the .cfg file later. Then close the window.

Now you can export the heightmap in raw format for RoR. In the landscape window, click "Export". Select the format "Raw 16 bits Intel Byte-Order" and save the .raw file.

Let's render the terrain texture. The simplest way is to use a terragen world file, that will set all the necessary parameters (texture colors, light parameters, rendering parameters). You can download the two world files I use: desert.tgw and badland.tgw. To use one of these, click the menu "World File->OpenWorld...". Of course you can experiment and change things. The only setting that should not be changed is the sun position (heading -60, altitude 25).

Now setup the camera: in the Rendering control window, click "Camera settings", check "orthographic", fill 3000,m in "view width", and click "Auto Setup". Your camera is ready to make a texture.

Review the rendering options, expecially the image size. It must be square and a power of two. Best size is 1024x1024. For a better quality, I render 2048x2048, then I downscale with Gimp to 1024x1024 to smooth-out small artifacts.

You are ready! Press "Render Image", and wait... Once finished, save it to bmp, this is you terrain texture.

Now you can do you miniature map by downsizing the terrain texture. Create a .cfg file, and remember to fill the correct max terrain height in it. Create a .terrn file, and you are set!