The Official Terragen Frequently Asked Questions

interface - animation - rendering problems - community - systems - technique - registration - terminology

Last updated January 31, 2004.

Interface

  • Sometimes, black dots may appear while rendering. This should not affect the final saved image.
  • The interface will not look as good when using Large Fonts mode under Windows. Unfortunately, there is very little we can do about this.

Animation

  • What do I do with the sequence of Bitmap files after rendering an animation?
    You need to use a third-party utility to convert the sequence into an AVI, MOV, MPEG etc. file. For AVI files, we recommend VirtualDub. Windows XP comes with the Windows Movie Maker which can also convert BMP sequences into WMV files.
  • My computer crashed halfway through rendering an animation - how can I carry on where I left off?
    You need to have saved your world and Terrain files for this to work.

    Open your script file in a text editor - One of the first lines you will see will be something like:

    initanim c:\anim1\anim, 1

    Change the number at the end of the line to the next frame to render (if 100 frames were rendered successfully, change the number to 101). Now delete the frame definitions for the frames that have already been rendered - In Camera Path Editor and Terranim, the beginning of the frame definitions are marked by a comment (line beginning with a semicolon) indicating the frame number.

    Start Terragen, and load the world and terrain files. Now execute the new script, and your animation should continue.

Rendering Problems

  • The sky doesn't reach all the way to the landscape, leaving a black area.
    In the Clouds dialog box, increase the Sky Size and try again.
  • When I render images, the colours do not blend together and instead are "banded".
    If your screen mode is not set to true-colour, you might get this effect while rendering, but not in the final (saved) image.
    If you still see banding in a final image, you may need to increase atmospheric accuracy.
  • When I render an image, it renders fine until the end and the entire image is replaced with grey.
    1. You may be behind a piece of terrain that does not show up in the preview. In this case, move the camera upwards.
    2. increase color depth to minimum of 24-bit (TrueColor)
    3. get the latest drivers for your video card from the vendor.
  • Some parts of the image don't seem to be rendered properly, missing out parts of the terrain.
    Make sure that the camera isn't under the landscape, or underwater! This can happen if you enter the z-coordinate of the camera manually, or sometimes by other factors. Setting the "Fixed Height above Surface" checkbox and entering an appropriate value (default is 1) can fix this.
    If this is not the problem, then try turning off Backface Culling (found in Render Settings on the Render Control dialog).
  • How can I reduce rendering times?
    Try reducing the "Sky Size" (in the Cloud Dialog). Often, you can get away with lower values before the sky doesn't cover enough area.
  • Why do low zoom values look so bad?
    Real-world cameras use a "spherical" lens, while Terragen does not yet imitate the effect of one.

Community

  • Where do I find Terragen Galleries?
    There are now so many galleries that there is no longer a definitive list available. A very large list can be found at TerraNet (although this inevitably contains a few broken links), while another option is the Terragen Webring.
  • What is TerraCon?
    TerraCon is a Terragen contest held every month or so, which is designed to tax the limits out of Terragen users.
  • What mailing lists are available?
    There are now several mailing lists, each suitable for different things. Click on the link for more information and to subscribe:
    terragen - the main list. Here you can ask questions about using Terragen, share tips, techniques and utilities and discuss anything Terragen-related. Off-topic chat is definitely not tolerated, though.
    terragengalleries - a list for announcements relating to Terragen galleries. Here you can post the address of your gallery.
    terragenfriends - a general chat list for users of Terragen, but not necessarily related to Terragen. Off-topic chat is most definitely encouraged.
    There are more mailing lists available - see the 'Resources' page for more.
  • What is the Shared Files Area?
    The shared files area is available to all Terragen Mailing List members. Frequently, list members will upload files there to explain emails better. To access it, log in to Yahoo Groups's Terragen area, and click on the link provided.

Systems

  • Terragen is not multithreaded. There is no advantage in using a multiprocessor system unless you want to have two copies running or other programs not slowed down. This will change in a later release.  Because of this, newer Pentium 4/Xeon processors will appear to only use 50% of the processor's capacity.
  • Support for computers/operating systems other than Windows and MacOS is unlikely to arrive for quite a while yet. However, it is planned that Terragen will eventually be ported (at least) to Linux.

Technique

  • How do I convert between Field of View and Zoom?
    FOV = 2*tan-1(1/Zoom)
    and Zoom = 1/(tan(FOV/2))

    where Field Of View is in Radians (degrees = radians * 180 / Pi).

    For photographers, there is a table comparing field of view, zoom and focal length here.
  • Where do I get information on improving my Terragen technique?
    Carol Brooksbank has written an excellent tutorial available at http://caroluk2.crosswinds.net/terratut/. It contains information suitable for beginners and more experienced users of Terragen. It is currently being updated for Terragen 0.8.

    Jo Meder has written an excellent Surface Map guide, available at http://www.planetside.co.uk/terragen/smgdl.shtml

    Another good way to learn Terragen is to join the Terragen Mailing List - here, over 800 users of Terragen exchange tips, techniques and compete in contests.
  • What are DEM files?
    DEM files are Digital Elevation Maps - data that represents the real world (or at least America). By using third-party programs or plugins they can be imported into Terragen so you can render pictures of real places. See the Terragen Resources page for more details.
  • Who writes Terragen?
    Matt Fairclough. Also involved with Terragen are John McLusky (who does support and handles registrations) and Jo Meder, who written the Mac version and has helped out in many other ways.

Registration

  • How do I register, and what do I get?
    You can register from the main Terragen Page. It currently costs US$79, with free updates until (but not including) Terragen 1.0, and a discount (at least $79) on the final version. You also get priority technical support by email, unrestricted render size, "ultra" antialiasing, larger terrain sizes and more bonuses in the future. Go on, you know you want to!
    Registration is compulsory for commercial use.
    Registration is by web (PayPal). All web transactions are secure.
  • What do you mean by "commercial use"?
    If you are making money from Terragen images, or using Terragen images in a product which costs money, it is commercial use and you will need to register. You do not need to register if you just want to put images on your (free to access) website.
  • If I'm a non-commercial user, can I have a key for free?
    Sorry, no.
  • I've registered - when do I get the keyfile? What do I do with it?
    Unfortunately, we (Planetside Software) only receive information on new registered users on working days. Therefore it might be a day or two before you receive your key by email if you register on a weekend. When you receive this key, place it in the main Terragen directory to unlock Terragen.  We aim to have registrations sent within 12 hours, though.
  • What if I lose my key?
    Send your original receipt by email to
    registrations@planetside.co.uk, and we'll send you a new one.  If you can, please let us know the full name on your key and when you registered - it will help us send a new one out quicker.

Terminology

  • Bank. The angle of "tilt" of the camera. Negative values of Bank correspond to a anticlockwise tilt
  • Canyonism. Sharpens the valley bottoms, creating an effect similar to canyons in the desert (although usually not quite so pronounced)
  • Corona This does not simulate what astronomers call the sun's corona. It is a halo around the sun which partly compensates for the fact that Terragen does not yet render lens flare. It has the effect of softening the edge of the sun's disc.
  • Density (Haze). The "effectiveness" of the haze.
  • Density Contrast. Has the effect of changing how "sharp" the edges of the clouds are, and will also make them appear darker under normal settings. The lower the setting, the softer the clouds are.
  • Density Shift. Allows you to alter how much of the sky contains clouds. Large negative numbers move towards having no clouds, large positive values move towards having a totally grey sky.
  • Detail. The level of detail used for both preview and final renders. The higher the detail is set, the smaller the triangles are drawn.
  • Exposure. Not just "lightness", Exposure mimics the exposure of a real camera.
  • Glaciation. Modifies the landscape by flattening valley bottoms and smoothing sharp changes in gradient
  • Half-height. The densities of the atmospheric components decrease as altitude increases. Half-heights specify the heights at which the atmospheric components are half as dense as they are at an altitude of zero. Lowering these "flattens" the atmosphere.
  • Head. The angle between the camera and target.
  • Pitch. The vertical angle of view with respect to a flat plane.
  • Preview. A small, low detail render which is used to get a "feel" for the current settings.
  • Realism. A higher setting generates a more realistic terrain with smoother transition between high and low. A lower setting can be used to create a more "craggy" landscape
  • Rendering. The process of creating an image from all settings used.
  • Roughness (waves). The vertical height of the waves.
  • Size (waves). The 'width' of waves.
  • Smoothing. Adjusts how smooth the landscape will be. Setting this too high can interfere with the realism setting and create unwanted results
  • Surface Map. Analogous to a texture, but is not an image. The surface map relies on altitude and gradient as defined by the user.
  • Surface. The Terrain and the Water layer combined.
  • Zoom. Increasing zoom does not simply give the effect of moving the camera closer to the target - it changes the field of view.


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©December, 2002 John McLusky