Graphics Programs Reference
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Figure 11-31: The textures for a single leaf, from left to right: diffuse, specular, and alpha. These textures are used on my
IvyGen mesh.
be no color change around the edges. I duplicated
the leaf image layer and placed it on top of this
background.
To remove the specular highlights, I used the
Dodge/Burn tool ( shift -D) set to burn (hold ctrl
or change the settings in the Brush Tools palette)
with a large, soft brush. I brushed lightly over the
highlights to dim them (use a light pressure if you're
using a pressure-sensitive tablet, or simply set the
Exposure setting of the Dodge/Burn tool down
low if you're using a mouse). To fix any areas that
become oversaturated, I used the Paintbrush tool
with a color from a good part of the texture. Then,
I set the blend mode of the brush to Saturation and
painted over any oversaturated areas to bring them
in line with the rest of the texture. (Figure 11-31,
left, shows the diffuse texture.)
images as I needed, skipping the specular textures
for the time being. Later, I combined all these leaves
onto a single map so it would be easier to do the
specular map afterward.
Combining Leaves onto a Single Texture
For most of the foliage in my scene, I packed all of
the leaves onto the same UV map. (In Chapter 10,
I baked a color map from the material color of
the leaves to serve as a guide.) To make it easier to
assemble all my leaves into one texture, I applied
the layer masks that I had created earlier to the dif-
fuse layer of each leaf texture. I then saved each of
these leaves as images and opened them as layers on
top of the guide image I baked in Chapter 10.
Next, I started arranging the leaves to fit the
map, using the Move, Scale, and Rotate tools. After
getting a leaf roughly in place, I used the IWarp tool
(Filters 4 Distort 4 IWarp) to warp the leaves to more
accurately fit the shapes I needed (see Figure 11-32).
IWarp allows you to move pixels around your selec-
tion fluidly in order to reshape areas of an image.
For the leaves, I used the Move Deform mode in
IWarp to fit the outline of the leaves to the shapes
I needed. I repeated this, duplicating some of
the leaves to cover each space that needed a leaf
texture. For the unwrapped stems, I cloned from
the bigger leaves to fill in the whole region with a
rough green texture. The diffuse texture for all the
leaves combined into a single texture is shown in
Figure 11-33. I then created the specular map for my
grouped-together leaves the same way I did for the
individual leaf.
Specular Map
For the specular color, I duplicated my masked
leaf image and used the Hue-Saturation tool to
desaturate it a bit. Then, I shifted the specular color
slightly toward yellow. I also painted in some high-
lights on smooth areas of the leaf and then blurred
the texture slightly. You can see the specular texture
in Figure 11-31 (center).
This completed the textures needed for a single
leaf, so I saved each as a .tga image and then saved
an .xcf file with my layers. I used this single leaf as
my texture for the leaves generated by IvyGen. For
the rest of the leaves in my scene, I wanted to com-
bine as many as possible into one image so that I
wouldn't have to manage too many textures. So I
repeated the cutting-out process for as many leaf
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