2008

Creating and Using Normal Bump Maps
Normal bump mapping is a way of adding high-resolution detail to
low-polygon objects. It is especially useful for real-time display devices such
as game engines, and it can also be used in rendered scenes and animations.
A normals map is a three-color map, unlike the grayscale maps used for regular
bump mapping (see
Bump Mapping on page 5382 ). The red channel encodes
the left-right axis of normal orientation, the green channel encodes the
up-down axis of normal orientation, and the blue channel encodes vertical
depth.
Basic Workflow
3ds Max provides a number of different ways to create and use normal bump
mapping, but the most straightforward and simplest workflow involves these
steps:
1 Create a detailed, high-resolution model.
2 Create a simpler, low-resolution model.
The low-resolution model should have the general shape and outlines of
the high-resolution model, and typically it should be a bit smaller, so
that projected detail in the high-res model will appear to be above its
surface.
3 Select the low-res model.
4 Choose Rendering > Render to Texture.
The Render To Texture dialog appears.
5 On the Objects To Bake rollout, in the Projection Mapping group, click
Pick.
A selection dialog appears.
6 Choose the high-res object, and then click Add.
3ds Max applies a Projection modifier on page 1556 to the low-res object.
7 In the Projection Mapping group, turn on Enable.
NOTE At this stage, often you will click Options to display the Projection
Options dialog
on page 6214 , which has a variety of settings for how to
generate the projection.
6182 | Chapter 18 Rendering