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WHAT'S UNDERFOOT?

SURFACE MAPS

Surface maps are what give the Terragen landscape its nature. They can be grass, rock, snow, soil, desert, or any combination of surfaces that you choose - including Martian or surreal or wherever your imagination takes you. I am going to be earthbound in this tutorial, and show you how to make natural looking surfaces for this world - you can take it from there and make your own extra-terrestrial ones.

rock surfaceThere has to be a basic surface which is present all over your landscape. The default for this is a neutral coloured rock. If you generate a terrain and render it straightaway, this is what you will see - blue in the water, but the land entirely rocky. There is light and shade where the sun strikes it, but there are no colour shades within it. It is monochrome. This section of the tutorial will show you how to change that, and give your landscapes character.

But first I want to show you the effects of some of the surface map editor controls. To access the surface map editor you click the EDIT button in the Surface Map area on the Landscape panel. We have only one surface layer at the moment, the base surface, so the edit panel will relate to that, but when we have added layers later, one layer must be selected, and its edit panel will appear when the EDIT button is clicked.

surface edit panel

bumpyAt the top of the edit panel are the bumpiness controls. To show you the effects of these, I generated this flat, but bumpy, landscape. Use this image as a comparison, to see what the effect of the various controls is. And in order to show the effects clearly, I added a child layer, and gave it a grass colour.

new layerTo add a layer to a surface map, you click the ADD CHILD button in the Surface Map area of the Landscape panel. Since we have only the base layer at the moment, the new layer is a child of that, and is shown as such in the Surface Map 'family tree' - the list of surfaces. Later, when we come to devise a more complex surface map, we shall be adding child layers to child layers. Clicking on '[New Surface]' in the list brings up the edit layer panel for that surface. The child layer edit panel has more options than the base layer one. But first, I want to change its colour, and that option is available for all surfaces, including base. To access the colour panel, click the COLOUR button near the top of the panel.

colour panel

The default colour for a child layer is a slightly warmer rock colour, but I want something which will contrast with the rock and show the effects of the options. You can set any colour you like by moving the sliders, but there is a realistic grass colour preset which you get by clicking the small green button. The sample squares change colour, and when you OK this box and return to the main panel, the sample circle is now displaying green, and this layer will now appear to be grass.

advanced distribution

The lower half of the edit panel has the distribution options. At the time of writing the Distribution Presets are not implemented, so we must use the Advanced Distribution tab. I will examine the options on this tab in detail later, but I wanted the grass to cover the rock completely, so I raised Coverage and Fractal Noise to maximum and unchecked Maximum slope. With this setup I can now show you what the bumpiness controls at the top of the panel do. I shall be working on the New Surface layer, and the changes I make will effect only that layer, and not the base layer itself.

smoothbumpyBumpiness, as its name suggests, controls the bumpy nature of the surface. In both of these examples, Mimic Terrain is reduced to minimum. On the left, bumpiness is at minimum. Although there is little texture in the grass surface, you can see that it is covering a bumpy surface underneath. On the right, with bumpiness at maximum, the grass surface bumpiness is so pronounced that the underlying nature of the terrain is virtually hidden.

To get a bumpy surface which also reflects the nature of the terrain, Mimic Terrain is also taken to maximum. (below right)

bumpy     bumpy mimics terrain

You can change the bumpiness and its relationship to the terrain underneath it, by changing the sliders.

The RESET BUMPS button makes subtle changes to the nature of the surface bumpiness. It does not affect the overall bumpiness, the degree of mimicing the terrain, or the nature of the terrain underneath, but it does affect the look of the surface layer you are editing. The type of surface bumpiness is displayed in the coloured example circle on the panel, and it changes each time you click the button. You can use this feature to fine tune the appearance of your surface, choosing a texture pattern that seems the most suitable for the surface and the terrain it covers. Below are three examples of the textures this button accesses, and the differences they make to the surface. The changes are subtle and not easy to see in images of this size, but you can see them if you look closely at the foreground area of each image.

bump1     bump 2     

The last option I want to look at in this section is on the Advanced Distribution tab - Depth. It affects both the amount of the surface which covers the underlying one, and the smoothness with which it covers. For the examples below, I returned Bumpiness, Mimic Terrain, Coverage and Fractal Noise all to the halfway position, so that the difference between the two pictures is entirely due to the effect of Depth. The one on the left - Depth at minimum - shows a slightly higher distribution of grass and a smoother appearance. On the right - Depth at maximum - there is slightly less coverage, but the surface is much less smooth, and shadows show the increased depth of the undulations.

depth min     depth max

On the next page I am going to generate a terrain, make modest adjustments to it to get the sort of scene I want, and then make a full surface map, using all the settings, including the other Advanced Distribution settings, to give the scene a natural appearance. We shall go on to use this same scene in later pages to examine the manipulation of sunlight, atmospheres etc., to change the appearance of the same landscape.

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