Graphics Reference
In-Depth Information
Another panel that springs to life with an image texture is
Image Sampling . It holds controls for a number of spe-
cialty items. The most important for general use are the
Alpha and Normal Map settings, both of which we'll deal
with later. This panel also contains the Flip x / y Axis
toggle, which rotates your texture onto its side.
Now we come to mapping. By our earlier criteria, a carpet
is definitely a surface texture. If you cut a floor in half, the
carpet texture does not go the whole way through. So,
Generated mapping (while it may or may not work depend-
ing on the geometry) is not what we want. Welcome to
the wonderful world of UV mapping.
First, UV mapping has nothing at all to do with UV light/
radiation. The letters are chosen because this mapping style
is a way of converting 3D coordinates (from your 3D
geometry) to 2D coordinates (flattened on a 2D image). X,
Y, and Z are already taken with keys and axes, and the next
two letters down are U and V. So, when you read, write,
or say “UV mapping,” think of the U and V as the cor-
responding 2D coordinate system that is used for images.
Set the Coordinates menu on the Mapping panel to UV,
but don't bother to render yet. We need to assign UV
coordinates to all of the faces in the floor model.
Extremely Basic UV Mapping
UV mapping is such an important and frequent procedure
in 3D work that it has its own screen. Use either the
Screens dropdown menu on the main header or the Ctrl-
Left/Ctrl-Right-Arrow keys to get yourself to the screen
called “UV Editing.”
The right half of this screen is a 3D view and some proper-
ties. The left is a new window: the UV/Image Editor .
This is actually the window type that pops up whenever
you hit Render, and is Blender's workspace for dealing
directly with images. In the 3D view, find the room and go into a top view (Numpad-7). It'll help to
switch to Wireframe and Orthographic modes (Z key and Numpad-5) if you're not already using them.
Figure 7.11   The  carpet's material  properties.
With the room selected, go into Edit mode. Using the A key, select all of the vertices in the room.
The term for transferring 3D geometry into 2D space is called unwrapping . Imagine the geometry
as a paper shell around a solid object—to flatten the shell onto the floor, you unwrap it. Bring up the Unwrap
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