.
Note:
The texture coordinates, or UVWs, are a separate storage
location on a two-dimensional plane. These values
typically range from 0,0 to 1,1, which are the upper-left
and lower-right corners of the image. These UVWs do not
affect the location stored in the XYZ coordinates. It also
works the other way around, as the XYZ coordinates do
not affect the placement of the UVWs.
Using the UVW Map Modifier
A UVW map is nothing more than a gizmo that will unwrap
your object for you. How it unwraps your object is based on
the gizmo of your choosing. You get seven basic presets when
choosing your UVW map: Planar, Cylindrical, Spherical,
Shrink Wrap, Box, Face, and XYZ to UVW. If you wish to
unwrap a box, then of course you would want to choose Box
mapping. If you have a cylinder you wish you unwrap, then
you would choose Cylindrical mapping.
To demonstrate quickly just how the UVW Map modifier
works, let’s create a cube within our Perspective viewport.
The next thing we need is a material that will allow us to see
how our unwrap is working. Open up your Material Editor and
open the Maps rollout.
The Maps rollout has several empty slots available, the
second of which is called the Diffuse Color channel. Diffuse
Color is simply our texture color. You can load many different
things into this slot, such as images, video, procedural tex-
tures, and so on. Click on the empty slot to bring up a very
long list of options. Choose Checker.
348 Chapter 17
Figure 17-6: The
Maps rollout with Dif-
fuse Color checked
and Checker in the
Map slot
Checker is a procedural texture that is nothing more than a
repeating checker pattern. Since it is procedural we can go in
and change things numerically to fit our needs. Go into the
Tiling boxes and set both to 10.
This gives us 10 checker tiles and allows us to more accu-
rately see the UVWs on the surface of our model. This is a
great use of the Checker texture. I guess you could use it to
make the floor of a ’50s burgers and shakes restaurant, but for
now let’s just use it to check our unwrap.
Drag and drop your new material
onto your cube and click the Show Map
in Viewport button.
The checker material we are using
should now be displayed.
Applying a checker pattern to your objects when you are
unwrapping them provides you with a visual aid to keep your
Using UVW Map and Unwrap UVW 349
Figure 17-7: Chang-
ing the tiling on our
Checker texture
Figure 17-8: The Show
Map in Viewport button
Figure 17-9:
The box with
the Checker
texture on it
UVWs straight and even. If your UVWs are laid out improp-
erly, then the checker pattern will be flawed, as shown in
Figure 17-10.
Our checker pattern looks good, but what if we wanted to
modify our cube a bit? Let’s adjust the width of the cube.
.
Note:
Any standard primitive will automatically generate its own
UV coordinates if you have the Generate Mapping Coords
box checked when you create it. That is why our checker
material is showing up properly. Of course, if we were to
modify the cube, then it would start to break down our
UVWs.
Scale the cube roughly 500% on the x-axis in your Perspective
view. As you can see, the Checker texture starts to stretch
out. If we were using a texture like cardboard, this would com-
pletely break the illusion of the box being made of cardboard.
350 Chapter 17
Figure 17-10:
Serious stretch-
ing in the UVWs
It’s the proper shape, but the UVWs are obviously horribly
stretched. This is where the UVW Map modifier comes in.
Select your cube and apply the UVW Map modifier from your
Modify panel. This will display a set of presets and options.
This is a pretty simple modifier that gives you a list of map-
ping options to choose from.
Sometimes these options will create a really good starting
point, and sometimes they will totally solve your unwrap
for you. In this case, we have a rectangle that we want to
Using UVW Map and Unwrap UVW 351
Figure 17-11: The horribly stretched checker pattern on our long
polygons
Figure 17-12: The
Parameters rollout
of the UVW Map
modifier (the
checker pattern
has been enlarged
for clarity)

Get Essential 3ds max 2008 now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.