Chapter 7.2 Introduction to Terrain ( Legacy )

Terrain System ( Legacy ) - The Terrain System provides a means of creating terrain geometry for large outdoor environments that automatically adjusts the level of detail based on proximity to the camera and allows for blending of multiple materials. It is complete with an editor that contains a suite of tools for modifying and manipulating the terrain(s). **NOTE** The Terrain System is being replaced by the Landscape system once that system achieves feature parity with the current Terrain System.
http://udn.epicgames.com/Three/TerrainHome.html

Terrain Editor User Guide
Editing terrain in UE3 is accomplished via the TerrainEdit dialog. This dialog combines the terrain editing toolbar with the layer browser capability to provide a single floating dialog through which the majority of terrain operations can occur.
http://udn.epicgames.com/Three/TerrainEditorUserGuide.html

Terrain Design

Unreal Engine 3 supports a flexible terrain system that provides a wide variety of visual styles and uses. Many different landscapes can be realized and various themes can be achieved utilizing a heightmap based system that can visually depict hills, valleys, mountains, rivers, roads, and more, plus a multi-layer Terrain Material system that supports real-world texture files such as dirt, rock, sand and mud. A multi-layer Decoration system provides additional flexibility and realism by rendering foliage such as grass, weeds, bushes and flowers, and even small rocks and debris.
http://udn.epicgames.com/Three/TerrainDesign.html

Using Terrain
Terrain was changed to a system where detail is now removed from the mesh as distance from the mesh increases. This allows for the designer to have control of the detail when the vertices are present.
http://udn.epicgames.com/Three/UsingTerrain.html

Setting Up Terrain

Walkthrough of the Terrain creation process
http://udn.epicgames.com/Three/SettingUpTerrain.html

Terrain Heightmaps Creating and importing heightmaps. Unreal Engine 3 supports two terrain design techniques, which include hand-painting directly on the terrain mesh to create the hills and valleys, and importing externally created heightmap files in UnrealEd's G16 bitmap or T3D mesh formats.
 http://udn.epicgames.com/Three/TerrainHeightmaps.html

Terrain Advanced Textures - Terrain texturing is an enormous subject with a wide variety of methods and solutions. This tutorial will cover a few methods available in Unreal Engine 3 for managing common video game terrain texturing issues, along with methods of improving the quality of terrain texturing and increasing detail. This tutorial is divided into sections of increasing complexity that show solutions for various texturing issues.
http://udn.epicgames.com/Three/TerrainAdvancedTextures.html

Terrain Alpha Maps - A Terrain is essentially a 3D planar mesh object that is x*y vertices in size. The actual number of quad faces that are rendered is x-1 * y-1. So a 256x256 terrain requires a heightmap that is 257x257 in dimensional size. The Terrain Properties dialog specifies the terrain size in patches or quad faces (NumPatchesX and NumPatchesY), which is equivalent to the vertex count -1.
 http://udn.epicgames.com/Three/TerrainAlphamaps.html