CG Modeling 2: NURBS - An Introduction to Computer Graphics for Artists - page 269

Fig. 14.32 NURBS vehicle model courtesy of Arlon Swaders

• If you want the open ends of any number of primitives to be seamlessly joined in
your polygonal model, you must take care to ensure they convert to the right
number of vertices at all adjacent edges. By counting isoparms on either side of
an adjacent edge, you can determine how many vertices you will get, depending
on the conversion method.
• If you need to match a closed edge to an open one of shorter or longer length, you
may have to account for vertex count discrepancies in the poly model. A limited
amount of manual control can solve the problem, but you must be careful with your
technique, to ensure that either side of the edge gets the right number of vertices.
• Polygonal objects are usually easier to map than NURBS objects because of the
more fl exible rules that apply to polygonal UV editing. After you have converted
your NURBS object, you may want to edit its UVs, to improve its texture layout.
This will almost always be something you wish to do. The only time you won't
is if you are modeling in NURBS specifi cally to take advantage of its embedded
coordinates.

14.5 Exercise: Vehicle

Any kind of vehicle or industrial design product will allow artists to practice
NURBS modeling, but automobiles made after 1985 tend to have more blend curves
than other types of vehicles or products, making them a good challenge for this
exercise. Feel free to try something simpler to start, but to really test yourself, you'll
want to try this exercise (Fig. 14.32 ).