Terrain and the Terrain Editor
The Terrain button opens the Terrain Editor.
A Terrain, in TKD3, can be used to generate geometry outside the track so that Segments and Stripes don’t “float” around but look connected by such an external Terrain. Terrain is rendered as a big, squared surface tessellated by many small polygons so that it can be “bended” into valleys and hills. Terrain is only visual, no dynamic interaction will happen between it and cars or other live objects.
The top controls, in the Terrain Editor, select the Material to be used for Terrain.
New/Delete Terrain controls are self-explanatory; before creating a Terrain you should, however, select the number of lateral polygons used to tessellate it with the Dim control (default = 1024) and polygons lateral dimensions with Dlx (default = 2 meters). Remember that the final Terrain lateral dimensions are the product of those two controls (ie a 1024 polygons Terrain tessellated by 2 meters long polygons will be a square with each side measuring 1024x2 = 2048 meters).
Once a Terrain has been created, it can be modified.
The Ut, Vt, At and St controls are used to texture Terrain, they are particularly useful if the Terrain Material uses a big texture (maybe an aerial view) to render the Terrain itself. Uv and Vt are used to “center” the texture, they are the normalized texture coordinates (from 0.0 to 1.0) that will correspond to the track starting point (first Segment starting point). At rotates the texture by the specified angle (in degrees) and St scales the texture, the lower the number, the bigger will look the texture.
Relax Terrain starts an algorithm that tries to fit Terrain to Segments; Terrain altitude is locally modified so that it follows Segments height. Terrain relaxing is a bit slow, so when you click the Relax Terrain button the algorithm is started in background and continues to work; meanwhile, you can navigate the track with the Preview window and see how the algorithm is working, when you’re happy with it click the Stop Relaxing button to stop the relaxing process.
Note: Terrain relaxing is not updated in real-time, in order to save CPU time, in the Track Preview window, unless you navigate it (in other words: if you don't do anything and simply stare at the Track Preview window, nothing will seem to happen).
Add Noise is self-explanatory: it should be used only after relaxing Terrain to add some Perlin noise to Terrain heights. Amp controls the amplitude, in meters, of the added noise, and Per controls the period of the main Perlin octave (the higher the number, the lower will be the spatial noise frequencies).
Note: Terrain relaxing doesn't work very well if you restart it many times after major modifications to the track (Segments/Stripes) altitude. In other words, if you relax the Terrain, then stop relaxing, then modify some Segments altitude, then relax the Terrain again and so on, you may get weird results. In that case, once you finish to modify the track altitude, it's better to delete the current Terrain, and rebuild/relax it from scratch.