It is often necessary to create new UVs for a surface
mesh in order to texture map it correctly. These situations include:
- Texture mapping a surface that doesn’t
have existing UVs.
This can occur when you
import 3D models from other software applications that don’t create
- When the UVs for a surface are badly
jumbled or are missing some UVs.
This can occur when a
surface has been edited or modified in some way and it becomes hard
to determine what UVs may be missing as a result.
- When you need a unique set of UVs for
a particular purpose.
For example, if you want
to paint a texture map directly onto a 3D surface, you may want
to map UVs that allow you to paint using the 3D paint tools in Maya.
Alternatively, you may want to create a unique set of UVs specifically
for baking textures or light maps.
Maya lets you create UVs for polygonal and
subdivision surfaces using a process called projection mapping,
also referred to as mapping UVs. Maya provides several
projection mapping types that map what gets viewed by a particular projection
to a flat 2D view that can be subsequently correlated to your texture
map using the UV Texture Editor.
In this lesson,
you use a feature called Automatic Mapping to create new
UVs for the cracker box model. Automatic mapping lets
you specify the number of planes that will be used for the UV projection.
Mapping is normally used when mapping UVs that require
multiple projections of organic shaped models as it has the advantage
of producing UVs that are proportional in scale to the world space
area of the mesh faces of the surface.
mapping is useful when your mapping requirements are
for non-overlapping UVs which fit within the 0 to 1 texture space,
but which do not have to be contiguous; for example, when using
the 3D Paint tool, Maya® Paint
EffectsTM, Maya® FurTM or Maya® HairTM.
You use Automatic
Mapping in this lesson because it can produce a UV projection
from three planar directions simultaneously which makes it a good choice
for the shape of the cracker box model. That is, you can map UVs
for the front and back, top and bottom and the two sides in one
operation. This projection type is referred to as a triplanar
To map UVs using Automatic Mapping
- In the perspective view, select the cracker
box as an Object.
- From the Polygons menu
Create UVs > Automatic Mapping > .
The Automatic Mapping Options window
- In the Automatic Mapping Options window,
select Edit > Reset settings, set
the following options, and then click Project:
- Planes: 3
- Percentage Space:
Setting Planes to
3 creates UVs based on projections from three separate directions.
Setting the Percentage Space option to 2 sets
the size of the space that appears between each of the separate
UV projections when they are laid out in the UV
When the projection is
complete the new projected UVs from the triplanar projection appear
in the UV Texture Editor.
NoteWhenever a UV projection
is performed on a surface, any existing UVs for the surface get
replaced by the UVs from the new projection. To avoid replacing
existing UVs you can explicitly save the UVs in a UV set. For more information
on UV Sets see the Modeling guide in the Maya
- In the UV Texture Editor,
dolly the view so it shows only the 0 to 1 UV range area that displays
the image for the texture map and the new UVs (as shown below).
the UV Texture Editor, select Image
> Dim Image.
The intensity of the
image map is reduced so you can view the UV borders on the projected
UVs more easily. The new UVs appear in the UV
Texture Editor as shown below.
- The six rectangular UV shapes, referred
to as UV shells or simply shells,
now match the aspect ratio for each of the six sides of the cracker
box better than the earlier UVs.
- The UV shells fit within the 0 to 1 UV
texture range. Automatic mapping fits the
UVs to the 0 to 1 range by default.
The texture map still
does not appear correctly on the cracker box because the UV shells
need to be repositioned so they align with the corresponding components
of the image map.
While the shape of each
UV shell is now recognizable as being associated with the cracker
box, it is not apparent which components in the UV
Texture Editor correspond to a particular face on the
In the next section you
learn how to select and reposition the UV shells so they better
match the image for the texture map.