Texturing Polygons
UV Mapping and using Photoshop to create textures
Some excerpts and definitions used were taken from the help section in Maya.
There
are many different ways to create textures for polygon models. The way
I will show you may not be the correct way to do this, but it is easy
and effective. Throughout this handout I will attempt to show you how
to select various parts of a polygon model and apply textures to them.
For those of you who have looked into this, we will not be sewing UVs
or anything like that. Like I said, this is a simple way to do complex
texturing on polygons. For this example I will be using a car that I am
modeling. It is a work in progress but will suffice for what I will try
to show.(Fig.1)
Fig. 1.
Now,
in order to assign textures to individual components there are a few
things you need to know. First we need to assign a texture map to the
various parts. There are three types of maps, located at Edit Polygons
> Texturing > The three types of maps are:
1.
Planar Mapping: Planar mapping projects UVs onto a mesh through a
plane. This projection is best for objects that are relatively flat, or
at least are completely visible from one camera angle.
2.
Cylindrical Mapping: Cylindrical mapping maps UVs by projecting based
on a cylindrical or spherical shape wrapped around the mesh. These
projections are best for shapes which can be completely enclosed and
visible within a cylinder or sphere, without projecting or hollow parts.
3.
Spherical Mapping: Cylindrical and Spherical mapping map UVs by
projecting based on a cylindrical or spherical shape wrapped around the
mesh. These projections are best for shapes which can be completely
enclosed and visible within a cylinder or sphere, without projecting or
hollow parts.
It is good to know what each does so you
can apply the proper map to your model. For the first example I will
use all planar maps.
I will start with the doors. First select
the entire object you want to texture.(Fig. 2.) Then go to Edit
Polygons > Texture > Planar Mapping □. Next, choose which axis
you want to project on (X, Y, or Z). Or, if you object is not lined up
with any of the three axiss, then you could just choose fit to best
plane and Maya will adjust the map to the best of its capabilities to
line up with the positioning of the object. (Fig. 3 - 4)
Fig 2.
.
Fig. 3.
Fig. 4
Now you will
see a map around your object (Fig. 5). Now to ensure everything is
uniform, assign a material with a checker map to the planar map on your
object (Fig. 6).
Fig 5.
Fig. 6
We will use this
checker map to keep all textures equal and ensure they line up and are
all in uniform to one another. In order to do this we want to be sure
we have a lot of boxes to work with in the checker map and be sure they
are all square. We do not want any stretching. SO, first we will
increase the size of the map and keep it in the shape of a box. To do
this, make sure the map is selected, then in the channel box, scroll
down to were it says projection width and height. Highlight both and
change the size to something like 30 or 35 (Fig. 7).
Fig. 7
You can now see
that the map increases in size greatly. We are only doing this because
with every other map we use, we want to do the same. This way all maps
are equal, thus projecting equal textures. So now we will open the
attribute editor for the checker texture, go to the place2Dtexture tab,
and increase to U and V repeat of it (Fig. 8). This will give us our
squares again. You can also see that the texture is a little blurry. If
you want to fix this to see the results better, open the attributes for
the material, scroll down to render stats, and increase the hardware
texturing (Fig. 9).
Fig.
8.
Fig. 9
After increasing the hardware texturing you can now see the texture more accurately (Fig. 10).
Fig. 10
Now
I will repeat these steps for the top and sides of my car. Since the
car is one full polygon I can use a cylindrical map or simply continue
with planar maps. This time I will select all of the faces I want to
project a map onto (Fig. 11).
Fig. 11
Next, go to Edit Polygons > Texture > Planar Map □ (Fig. 12). Then choose the axis you want and project the map (Fig. 13).
Fig. 12
Fig. 13
Then,
just like before, adjust the height and width of the projection map to
match the previous one (Fig. 14). Now assign the same material to it
and everything should line up equally on both parts (Fig. 15).
Fig. 14
Fig. 15
Now just continue until we have the entire car set with maps. Figure 16 below represents the final results.
Fig. 16
.
