How do you change your Sim's height?

I realize this is a really old thread, but there are still a few of us playing Sims3 (and the answer might also apply to Sims4--I can't say for sure, since I don't play it).  Anyway, the answer is yes, you can adjust height.  But not directly, since there is no slider for it.

You do it using the randomize button located at the bottom of the panel on the upper left portion of the CAS screen.  Although the sim that first appears in CAS is always standard height, if you click on randomize, all the sim's characteristics change, including height.  (And there's a wide variety of heights available, including at least two that are taller than standard and a bunch that extend almost to the bottom of the screen.)

Of course, this is easiest to do when you're creating a new sim.  You just keep clicking the randomize button until you have a sim that's the height you want, then make all the other adjustments as you normally would.

Changing the height of an existing sim is more difficult.  After randomizing, you have to recreate the original sim by returning all the sliders to same values they had before.  It's doable but very tedious.

I only started using this feature a few days ago and haven't tested it extensively yet.  But so far, all the animations work fine at each life-stage.