Techniques

Terragen Classic Basics for Windows

by John Labrenz | March 6, 2010

Terragen Classic screenshotTerragen Classic is a free stand-alone scenery generator for non-commercial use. Terragen creates photorealistic images up to 1280 pixels wide, based on your inputs for terrain, clouds, water and atmosphere. You can choose whether to make earth bound images, or if you like, create a view from Mars. Camera angle and height, sun angle and height, water reflectivity, atmosphere haze, along with cloud density and color are all adjustable. Terragen Classic is a great way to find out if you really like synthesizing landscapes risk-free — except for your time of course. If you want greater capability in image size, you can register your copy of software, or opt the greater capability of Terragen 2. A huge variety of terrain files are available online. The aim of this tutorial is to give you an overview of basic program controls using a starting file set; this is not meant to be a comprehensive tutorial on Classic Terragen.

Step 1

First, you must have Classic Terragen installed on your computer. Classic Terragen is available for free download. Choose either the Windows or Mac version according to your platform. A Mac version of this text is available.

Once installed, Terragen is ready to go. You can go build your own terrains, add your own surface textures, construct your own atmospheres, etc, and render to your hearts content. Alternatively, to shorten the learning curve, it is much easier to start with a pre-built terrain and pre-built parameter set (called a “world file”).

Step 2

There are many sources on the web for free terrain and world file downloads. A little searching will find enough downloads to keep you rendering for a long, long time. For the subject of this tutorial, we will be using a terrain made available here.

The terrain is “American Dream.” Click the image to download the zip file to your computer. You will need to unzip this terrain into its native .ter format for use within the program. Please respect the “non commercial” conditions at the top of the page and give credit to the author of the file.

Step 3

All the parameters required to render a scene are contained in “world files.” For this particular terrain I have constructed the following world file called “Naturescapesnew.” It is available for download.

So, now we have the three components necessary to begin rendering: 1) Terragen program installed; 2) Terrain downloaded; 3) World file downloaded.

Starting Classic Terragen

When you start the program you will be faced with the Rendering control screen and the Landscape screen as shown below.

 Rendering Control screenshot

Now let us load up the world file that you downloaded before. Go to “world file,” then “open world.”

 World File screenshot

Find the Naturescapesnew.tgw file on your computer.

Next go to the Landscape screen, click on Terrain > Open and find the DTH-American Dream.ter file on your computer.

 Open screenshot

Note: The unregistered version of Terragen Classic only allows a maximum terrain grid size of 513 X 513. We will therefore need to re-size our downloaded Terrain as follows:

  • Go back to the Landscape screen above. Click on the “size” button in the top right hand corner.
  • A Landscape settings screen will pop up. Click on the 513 grid point button at the top of the screen.
  • A “Confirm New Terrain Map” screen will pop up. Click on the “Yes” button.
  • A “copy and resize Terrain” dialog box pops up. Click on the “Yes” button.
  • Another dialog box pops up that reads “Adjust the point spacing” click on the “Yes” button.

We’re almost there! To finalize the terrain sizing, click on the “OK” button at the bottom of the Landscape Settings dialog box.

Rendering

Your screen should now look like this:

 Terragen settings screenshot

Now comes the magic. Go back to your render control screen and hit “Render Image.”

 Render Image screenshot

Presto! Congratulations, you have just rendered your first Classic Terragen landscape.

 Image - New screenshot

So that’s pretty simple, but you want to render your own concept right?

OK, let’s go to the Landscape screen. Click on the image of the terrain. You will see the following Landscape View/sculpt screen pop up.

 Landscape View/Sculpt screenshot

Experiment a bit. Right click inside the screen to move your camera location. Left click to obtain a new camera target. Once you’ve found something you like, go back to the render control screen hit render preview to see your new view. You can also fine tune the camera settings by inputting numerical position data directly into the render control screen.

 Water icon

Water
Things look pretty dry so far. Can Terragen render water? Of course! Click on the water icon to pull up the water parameter screen. To start, put in a water elevation of 600m and hit “Update Maps.”

 Update Maps screenshot

The water elevation will now show up as blue on your terrain maps.

 Landscape View/Sculpt screenshot

Do a quick Render Preview to see what things look like.

The water parameter screen also contains numerous setting allowing you to adjust wave properties, reflections, water colors and transparency, as well as shoreline foam effects. I encourage you to play with each of these settings, try a test render to see what effect they have.

 Clouds screenshot

Clouds
A quick click on the cloudscape icon gets you into the cloud parameter screen.

 Cloudscape screenshot

Again, here the options are numerous – everything from cloud color to altitude to density. When adjusting parameters, don’t forget to press the generate clouds button and update the view. Then do a render preview to see the result. Also note that what shows in the cloudscape screen will be a top down shot of the cloud layer. Therefore, moving your camera around will give you different cloud views from the ground. Give it a try!

 Atmosphere icon

Atmosphere
One of the most powerful tools in the Terragen arsenal is the atmosphere parameter set.

Atmosphere settings change not only atmosphere colors, effects, and mood but can also dramatically change the appearance of surface texture colors themselves.

 Atmosphere window screenshot

The atmosphere set consists of three components:

  1. Haze
  2. Atmospheric blue
  3. Light decay

The overall effect of each of these components is described beside each item. Using the Haze settings as an example, increasing density increases the density of the fog. Increasing the half height increases the altitude at which the fog begins to take effect.

Again, in this example using the original world file, note from the Rendering control panel that the camera sits at an altitude of 969.9m, but is at 650m above the surface. So, ground level where the camera sits is about 319.9m.

Note: If you’ve kept your water elevation at 600m from before, reduce it back to 0m again to see the following effect.

Put in a number of about 160m for the haze half height. Do a quick render preview. You should begin to see some fog developing in your render. As you increase your half height, the fog becomes more and more pronounced!

Now, if you go back to your water elevation screen and put back in 600m for the water elevation and do a render preview, you will notice that the fog is gone. Why? Well, the fog is there but it is now under water. You will need to go and increase the elevation of the haze half height. Try 300m for the half height and you will see the fog appear again.

As another example, if you’ve moved your camera location around from that set out in the original world file, you may find that the atmosphere doesn’t render. Note that the sky elevation is set at 2100m in the cloud parameter dialog. So, if your chosen camera elevation is above 2100m, the sky will not render. To fix this adjust either the sky elevation or the camera elevation accordingly. It is important to note the relative elevations of the terrain, the camera, the water, etc. to ensure that your parameters will show up properly in your final render.

The effects on both the atmospheric blue and light decay parameters work in a similar fashion to the haze. Give them each a try to see the effect on the render.

 Lighting iconLighting Conditions
Another powerful tool is the lighting control panel within Terragen. It contains numerous options to adjust lighting angles, position, strength, colors, appearance of the sun, background light and lighting effect on the atmosphere.

 Lighting Conditions window screenshot

Left click inside the sun heading and altitude screens to change the sun’s position. Other parameter modifications are for the most part self explanatory. Again one of the best ways to see for yourself is to adjust each one individually and note the effect they have on your render.

 Landscape iconLandscape
This parameter set has been left until the last because it is often causes the most confusion.

The surface map is what defines your surface textures. It defines not only the color but also the distribution.

The surface map always starts with a base layer. A base layer exists everywhere! Subsequent layers will cover a layer that appears before it, but you control its distribution effect on that preceding layer.

Landscape window screenshot

In this world file case, we have in essence, only 5 primary layers: Surface (Base), Mountain 1, Mountain 2, Mountain 3, and Veg.

You will note that the mountain 2, 3 and veg layers have a + sign next to them…that indicates that they have child layers. Click on the + sign to expand them further to see their child layers. A Child layer only affects it Parent layer. So, you can consider a layer that has child layers to be a highly refined Parent layer.

If you double click on the mountain 1 layer, you will bring up a the surface texture parameter screen:

 Surface Layer window screenshot

On the upper half of the screen, you can modify the texture color and bumpiness. Under the advanced distribution tab below, you are able to control the exact coverage of this layer. If you adjust the coverage slider to the right, more of the terrain will take on this attribute. You can also adjust the “noisiness” as well as altitude and slope constraints. Similar adjustments can be made to each surface layer. Hovering your mouse over each parameter will bring up text help describing control parameters.

If you wish to add, remove or reposition layers, go back to the Landscape tab and press the appropriate buttons on the right hand side of the screen.

One really good way to see what effect the layer controls have is to add a brand new layer and give it a bright color (white or bright green work well). Do a render preview and see where and how it shows up on your terrain. Then go back and make some adjustments to that brightly colored layer and take a look at the effect of your change and how it now appears on your terrain.

Basic File Functions

Once you have modified all the parameters and you found something worthy of rendering, don’t forget to save the world file! Also note that you can save surface files, atmosphere files and lighting files separately. That means you can open an existing world file then go and select another atmosphere file that you created for another render, apply that atmosphere file to the new world file.

Summary

Although classic Terragen is a relatively small program, it is quite powerful and flexible in allowing you to modify terrains and scenes from the realistic to the surrealistic. The only limit is your imagination.

Do not limit yourself to one world file set. Play with each of the parameters, do render previews to see the effect of each change and save the parameter sets that appeal to you! Try different terrains. In addition to computer created fantasy terrains, with a little searching on the web you will also find free terrains of actual earth features such as the Grand Canyon, Mount St. Helens, etc.

Most importantly, HAVE FUN!

Again, this tutorial was not intended to be a comprehensive screen by screen review of controls, merely an overview of basic concepts with a given world file and terrain. There are numerous detailed tutorials available on the web. One of the best places to start is the Terragen website itself for plug-ins, terrains, forum, and tutorial links.

About the Author

John is a Chemical Engineer who lives in Alberta, Canada. He is an avid fly fisherman of over 30 years whose lifelong interest in photography has been reignited with the advent of DSLRs. Although John focuses primarily on photographing landscapes, cooperative insects occasionally provide him with opportunities to shoot macro subjects as well. Some of John's images can be seen in his NatureScapes portfolio.

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