Creating and Editing Texture Coordinates (UVs) - An Introduction to Computer Graphics for Artists - page 177

10.8 Conclusion

When you edit UVs, you are unfolding and cutting your object into two-dimensional
space. You are like a costume designer taking a costume apart at the seams, and then
fl attening it out and arranging it with other sections of fabric from the same roll
to reconstruct the original uncut fabric from which it was made. Unlike fabric, the
polygons used by CG artists are not fl exible.
Keep in mind as you work that a good UV solution is almost always a compro-
mise between distortion and seams, and that most models contain some distortion
and some seams. You cannot realistically expect that you can totally eliminate both.
Editing UVs then, is an art of judicious compromise. If done well, your UV sets will
be a major feature of a more effi cient, easier to render, better-looking model. If not,
your models may not meet minimum professional standards.

10.9 Exercise: Alignment Illusion, Part 5

If you open your alignment illusion project now, it should be a fairly clean fi le apart
from its UVs. To put the information from this chapter to use, you should now apply
UVs to all of the polygons in your scene (Fig. 10.44 ).

10.9.1 Criteria

• All of the UVs must be set to the same scale. To do this, make a reference cube
(Sect. 10.2.5.3 ).
• Reduce distortion to as close to zero as you can. For the subjects in the illustrations
provided in Sect. 6.5 , this should be fairly easy.
• Overlapping UVs are allowed for repeated elements. If you choose to use over-
lapping UVs, try to put some variety into the way it is done, so that tiling is
not evident.
• Plan ahead for the texture map size you intend to use for the objects in your
scene. This is because if you don't, you are likely to have zero map area errors.
• If you have repeated objects, it is easier to attach UVs to one of them, delete the
rest, then copy the object with edited UVs as many times as needed to replace the
previous versions of the object.
• Plan for a high resolution mapping layout. This means you will have a fairly
large number of texture maps for your scene. For environments like those in the
images included in this topic, 100 textures is a good target for the number of
maps. It is possible to texture it with a low resolution treatment, with between six
and ten maps, but this is not appropriate for the kind of rendering you will make
with this fi le later.