You know, adjusting and manipulating pitch is probably the single most important thing you can do when tuning Vocaloids in order to make them sound realistic.
The problem, though, is that doing it by hand (drawing pitch curves) is extremely tedious, not to mention, very inaccurate. It involves a lot of trial and error until you get it to sound the way you want it to.
This is why I love the Vocaloid 5 Editor. With Attack and Release effects, you can save a lot of time and cut out a lot of that trial and error. And, if you don't find an attack or release effect that is quite what you're looking for, you still have to old tools available to you to manually draw the pitch curve.
Unfortunately, Yamaha does not sell the Vocaloid 5 Editor by itself. You have to buy a package, either Standard or Premium. Buying a package saves you a whole lot of money in the long run because--in the case of the Standard package, you get four Vocaloids with it. But it's a pretty steep initial investment.
Whereas, if you buy a Crypton Future Vocaloid (like Miku V4 or Rin), they give you the Piapro Studio VST plugin. It's not as full-featured as Vocaloid 5, but you can still pretty much do everything you need to do with it.
Let's take a look at the Enka attack in Vocaloid 5. It's one of my favorites! Here is what the pitch curve looks like.
|Enka attack in Vocaloid 5|
Let's see if we can replicate it by drawing the pitch in Piapro Studio!
|Replicated Enka attack in Piapro|
Not quite the same, but kind of similar! That's what you get when you're trying to draw a curve with a computer mouse!