Texture Painting - Blender Master Class: A Hands-on Guide to Modeling, Sculpting, Materials, and Rendering - page 162

2. This lets you modify the values of each channel

(red, green, blue, and alpha) in an image using
a curve function.

texture that complemented my texture nicely. I
opened them as layers in my texture image file and
scaled them so that the scale of the wrinkles in the
texture roughly matched those of the Bat Creature.
I used the Move tool to spread out the textures
on my image, knowing that their precise placement
wouldn't be important for the time being. I then
created a new layer ( shift ‑ ctrl -N or Layer 4 New
Layer) and set its blending mode to Overlay. Next, by
dragging the layer's icon in the Layers dialog up or
down, I placed it between my original color texture
and my Ambient Occlusion layer in the layers stack.
Using the Clone tool ( C ), I first set the clone
source ( ctrl -click) to one of the skin textures, mak-
ing sure it was selected in the Layers dialog first.
Then, I switched to my new layer and began cloning
the skin texture in various areas (see Figure 11-12).
I frequently switched between the different skin tex-
tures to find areas that would suit the different parts
of my creature's skin. I also used the Flip ( shift -F)
and Rotate ( shift -R) tools to flip and rotate the skin
images to see whether they worked better in dif-
ferent orientations before cloning. To get at areas
hidden by the skin images, I toggled their visibility
using the eye icon in the Layers dialog or simply
moved them to one side with the Move tool.
With a first layer of detail built up from photo
images, I hid the photo textures and started work-
ing on some hand-painted details (see Figure 11-13).
First, I added some veins to the wings on a new layer
using the Paintbrush tool and a soft-edged brush.
Next (on another new layer), I added some spots to
the skin in areas like the shoulders, temples, and
back in both darker and lighter colors. The Grunge
brush I used earlier works well for this with the spac-
ing (found in the Brushes dialog) turned up higher,
as does a simple, small, hard-edged brush for paint-
ing specific spots. Keeping different kinds of details
on different layers makes it easy to mix and combine
them in different ways and comes in handy when
creating specular and other kinds of maps.

3. To add red to the darker portions of the image,

select the red channel from the Channel drop-
down menu, grab the bottom left point of the
curve, and drag it upward (see Figure 11-11,
bottom).

4. Click OK to apply the curves, and the ambi-

ent occlusion map now gives nice saturated
crevices and shadowed areas to the skin (see
Figure 11-11, top right).

Saving and Exporting Back to Blender

The texture isn't finished yet, but it's important to
save often, and doing so can be a useful way to see
how our current work-in-progress texture looks in
Blender on the model. GIMP distinguishes between
saving ( ctrl -S) in its native .xcf format, which pre-
serves layers and other information, and exporting
images to other formats, such as . jpg or . tga ( ctrl -E).
We need to do both so that we have the GIMP file
with all its layers available for further editing as well
as an image that we can use in Blender.
First, I saved my image as a .xcf file, and then I
exported it as a .tga image. To open this image in
Blender, I selected my Bat Creature object, switched
to Edit mode, and in the UV Image editor, used
Image 4 Replace Image to swap the old, roughly
painted texture for the new one. (Remember to do
this for the material, too—though if you used the
same image for the texture as you applied to the
mesh, it should update automatically.) You should
then see your updated texture on your mesh. You
could now start painting in Blender again, but I
opted to stay in GIMP for the moment.

Adding Details

Back in GIMP, with our ambient occlusion now
working well alongside our painted texture, we can
start adding more details. I used a mix of hand
painting and photographic textures.
To start, it's handy to build up some texture
using photos, followed by adjusting and supplement-
ing the existing texture with some hand painting.
To that end, I grabbed some elephant-skin photos
from CGTextures, with some wrinkles and skin

Nails and Teeth

The nails and teeth of the Bat Creature are included
in the same UV map as the body. For the nails, I
painted a dark purplish color with some brighter yel-
lowish highlights. For the teeth, I used a yellow color
with some brown near where the teeth would meet
the gums, as shown in Figure 11-14.