EA made a lot of changes to Build Mode for Sims 3.  The first obvious change was to move items out of the square button based menu, and give you a collection of graphics to click on.  This is a little annoying, since it doesn't add anything to the user experience.  Beyond having to learn where everything has gone, of course!

If you mouse over the graphic menu, you might notice that Build Mode now has a "Foundations and Decks" sub-menu.  This lets you build actual foundations (key for creating a realistic mobile home or castle) and decks (no more having to slap wood panel flooring in the yard and call it a "deck"!).

Create A Style is also an option in Build Mode, and if you haven't tried out Create A Style, you should do so as soon as possible.  One of the best things about CAS is that it allows you to give your entire house (and its contents) a cosmetic makeover without having to buy everything new.  Don't like the wallpaper?  Fire up Create A Style and change it to any color or pattern you like!  Stove doesn't match the floor?  Edit its color scheme in Create A Style!

The real surprise is that any items come in different colors to begin with.  A lot of people have complained that Sims 3 doesn't ship with very many items in Buy Mode.  I suspect that they are mentally comparing the number of color combinations available in Sims 2 with the relatively limited set in Sims 3.  If you can change the color of your refrigerator to anything you like, why bother selling it in different colors in Buy Mode?

It takes a bit of practice to get used to Create A Style.  Every item that you click has a palette of 2-4 different color options.  Click on the palette color down the left-hand side to change it in the center of the CAS pop-up window.  You can select the color from the color wheel, choose a pattern from the drop-down menu at the top, or switch to "#" and paste in the HTML color code.

Using the HTML color code is handy when you want to coordinate colors across a range of items.  The HTML color code is precise, so you don't have to worry about hitting the exact same spot on the color wheel every time.  Simply choose the color you want, toggle over to the color code mode, copy the color code, then paste it back in for every color you want to change.

Of course, the most revolutionary change in Build Mode is the ability to drag walls of existing rooms.  This too takes a bit of practice.  Using the Hand tool, you have to grab the wall just right.  When you're getting close, a pointy icon will appear on the wall - either red or green, depending on whether you can or can't click to drag the wall.

Using the "drag wall" feature, you can pull out the walls of a room to make it larger.  The game will automatically continue the flooring and wallpaper for you.  Remember how tedious it was in Sims 1 and Sims 2 to expand a room, then have to go back and find the exact same flooring and wallpaper so that you could fill in the blanks?  No more!