Graphics Programs Reference
In-Depth Information
the input for textures, it's often convenient to refer
to “an image used to affect a material's diffuse
color” as a
diffuse texture
for short.
In general, when I refer to baking textures, I
mean an image
used
as a texture. As this would rap-
idly become tedious to read, I'll often instead use
the term
texture
more loosely—particularly as the
process of baking images is so frequently referred to
as
texture baking
.
The term
map
when used in the context of
textures (such as
texture map
,
diffuse map
, and
displacement map
) refers to an image used for a UV
unwrapped object—one in which each point on the
object can be mapped to a point on the image.
In this topic, I often talk about
assigning
an
image or texture to an object. Assigning an image
to an object is different from assigning a texture.
Texture-Baking Controls
To bake a texture (technically, an image—from
here on I will use the two terms less rigorously) in
Blender, use the Bake panel in the Render tab of the
Properties editor (shown in Figure 10-1). This con-
tains all of Blender's settings and tools for baking
texture maps, including the following:
Bake
This button bakes images for the currently
selected objects, using the bake settings you've
defined.
Bake mode
These settings are used to set what
kind of map you are baking.
Clear
This option clears the texture and replaces
it with black before baking.
Margin
This option extends the baked textures
out beyond the edges of the UV islands by the
number of pixels you set to prevent seams show-
ing on the mesh.
Assigning an Image
When I assign an image to an object, I link that
image with the object's active UV coordinate set.
This causes the image to be displayed on the object
when using the
Textured Solid
shading option in
the 3D Viewport (found under Display in the 3D
Viewport Properties region). It also means that
when baking images, this will be the image that is
baked to.
To assign an image to an object's UV coordi-
nates, select the object in the 3D Viewport and press
tab
to enter Edit mode. Hit
A
to select all, then in
the UV Image editor (I'm assuming here that the
object has already been unwrapped), use the drop-
down menu in the Editors header to select an image
to assign to the active UV set.
To create a new image and assign that instead,
use
Image
4
New Image
to create a new image to
bake to with the size and properties you specify.
Selected to Active
This option enables baking
from one mesh to another.
Distance and Bias
These settings determine how
far Blender will look for the surface of the other
mesh when baking from Selected to Active.
In order to bake a texture, Blender needs two
inputs:
• A mesh with UV coordinates that you want to
bake textures for. This must be selected as the
active object, and the UV coordinates you want
to bake to must be the active set.
• An image to bake the texture to, assigned to the
object's active UV coordinate set.
With these inputs in place, click
Bake
in the
Bake panel to have Blender render the texture.
Blender should render the map type dictated by
the Bake Mode setting (see Figure 10-1) and take the
following into account when baking:
Assigning Textures
Te x ture s
are assigned to materials, which are then
assigned to objects or parts of objects. Textures
are used to affect how an object will be rendered
and also as inputs for some modifiers. To assign
a material to an object, go to the Materials tab of
the Properties editor to choose a material from the
drop-down menu at the top of the tab or create a
new material with the
+New
button. You can then
assign textures to this material in the Textures tab
in the same way.
Selected objects
Blender will bake textures for any
selected objects that have UV coordinates with
an image assigned to them. You can bake mul-
tiple textures at once, as well as baking multiple
objects.
Other objects on currently visible layers
Unselected objects will not be baked, but when
baking lighting or other maps that are affected
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