Part 1: Modeling the Nissan R390 GT in 3ds max 5
>> Section 3: Caging and Surfacing

So, now we are going to finally connect the splines, which already form a visible "cage". At this stage we don't really need a 100% accurate cage, it's just there to give us a good starting opint. Adding and deleting edges will be quite easy later.
Remember to keep the near vertices coincident in space for the next steps: when you have all of them good splines layed out, select them one by one, enter in vertex sub-object mode (shortcut is "1" on the keyboard, very usefull) and check that you have vertices at the intersections. Again use vertex snap to make intersecting splines vertices coincident. Again, this is quite important as later we will apply a surface modifier which operates only on 3 and 4 sided closed splines. Once you have double checked all of your vertices, it's finally time to surface the splines.

First off, select one spline. Then click on "attach multiple" and, from the panel that pops up choose "all". Now you have 1 single object made of several splines (Fig. 6). For the last time, you have to be sure all (as usual, don't be afraid if you miss one intersection o two, you can always fix it in the next step) the intersecting splines have coincident vertices at the intersecting points, so you can proceed to the next step.

Add a "surface" modifier to your object, and lower the "steps" to "0". A mesh will magically pop up in place (no, it's not your finished car, you x**§|ç!!!) (be sure to be in a shaded viewport, F3 on the keyboard, or you won't notice any differences). Probably you will get some holes here and there (at least, i always do!)(Fig. 7): this means that there's either a part with more than 4 sides, or that some vertices are not in the same position. In some cases it's obvious how to fix a hole (just go in back to your spline in the modifier stack and then in vertex mode, snap-move the incriminated vertex to the right position and voilà, a face is created). In other situations it can get complicated and time consuming (especially if the hole is caused by having more than 4 edges for a polygon). If you cannot fix it now, once again you are lucky so don't worry, just try to keep the holes to a reasonable number, we will cap them in the next section!