I've worked with polygons a lot but there are also curved surface types in Maya called nurbs. Except for my very first book, I haven't spent a lot of time going over them so I was happy to see this book focus a bit on them. Here I'll be making a scooter (mostly) out of nurbs. So I start with the tire by drawing a cross section curve and then revolving that to make the tire. For the hubcap, I drew another curve and revolved that as well.
Next is the part of the scooter that covers the front wheel. I started with a nurbs sphere and squashed it and then made it bigger than the wheel. Then I drew a curve, projected that curve onto the sphere and then deleted the bottom portion of the sphere.
Next is the main frame of the bike. Previously, I've drawn two curves and created a surface connecting those two. Using the same technique, I started with a circle, squashed it and then duplicated it a lot and positioned them accordingly. Then I was able to connect them all together.
I used the same method to make the cover for the steering column. The headlight was created with some simple nurb shapes. The rear engine cover started out as half a nurbs sphere. The seat was created by drawing two top view curves that were then connected with surfaces which were then pushed and pulled to get the right shape.
At this point the rest of the bike was made using polygons which included the handle bar assembly, suspension for the tires and the springs and base under the seat. Some of the parts have an trim on the edge. This was created by making a small circle representing the cross section. Then I selected the edge I wanted and a tube was formed along that edge using the first circle as a guide.