Page 863 - Kitab3DsMax

Creating Baked
Textures and Normal
Maps CHAPTER

D games pose an interesting dilemma—creating interactive scenes that are
displayed in real time with the highest quality graphics. To achieve this, IN THIS CHAPTER
3game developers use a number of tricks designed to speed up the render-
ing time. One of these tricks is pre-rendering textures that include all the lighting Using channels
information and applying these pre-rendered textures as texture maps. This Using the Render to Texture
allows advanced lighting solutions such as global illumination to be included interface
within a game without requiring extra time to render such a complex solution.
The process of applying pre-rendered textures as maps is called baking a texture. Creating normal maps
Rendering textures is a significant part of the rendering process, and baking a
texture doesn’t remove this step; it simply completes the step beforehand, so that
the game engine doesn’t need to do the texture calculations.
Another common efficiency trick is to use normal maps. Normal maps calculate
the lighting results used to light small details that stick out from the surface of an
object. These details are then re-created using a normal map that is applied back
onto a simplified version of the object. The normal map allows these details to be
simulated without the extra polygons used to create them. By allowing simple
base objects to have details such as bolts and rivets without the extra polygons,
the objects can be redrawn quickly without losing their visual quality.

This chapter covers some of the features found in Max that enable the amazing
graphics that are found in the latest real-time games.

Using Channels

When 3D models are used in games, the color and material data for the models is
stored in channels. The game engine then knows that if it wants to change the
color of a group of vertices because of an explosion that has happened, it just
looks in the preset channel, finds the vertices it needs, changes the color, and
then goes on with the game.

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