There are several ways to change the physical appearance of the non-playable characters (NPCs) that populate the neighbourhoods of "The Sims 2." You can use a program like SimPE to change the outfits NPCs wear but this is an out-of-game solution. With ChristianLov's Sim Boutique Clothingrack, you can change the clothing of any neighbourhood NPC from within the game with a free item available in Buy Mode. If you want an entirely new slate of NPCs and Townies in your neighbourhood, you can use the boolprop cheats mode in-game to generate new NPCs and Townies different from the slate of regulars the game automatically generates and which appear in every neighbourhood.
Download and extract the package file. Move the extracted folder to your Downloads folder to install it. Typically, this is: documents\EA Games\The Sims 2\Downloads
Start a game and purchase the clothing rack. It can be found under the "wardrobe" tab in "misc." Place the clothing rack wherever you like.
Left-click on the clothing rack, select "Neighbor Buy" and then "NPC." The selected NPC will appear in your home and a shopping menu will appear and allow you to have the NPC purchase the clothing you would like it to wear. Select the clothing of choice, add it to the cart, then select "Accept."
Navigate to the clothing type you have just purchased in the "Change Outfit" menu that appears, select the new outfit, and then "OK." The NPC will change his or her clothes, then disappear.
Create a new neighbourhood by selecting "create custom neighbourhood" from the start menu. It's the icon that looks like four houses with a plus sign over them. Select the details of your new neighbourhood (layout, name, and terrain). After the neighbourhood loads, exit the game.
Navigate to the "Characters" folder for the neighbourhood you've just created. Typically, this is: My Documents\EA Games\The Sims 2\Neighborhoods\N00x\characters. The new neighbourhood should be the highest number since it is the most recent one you've created. Delete all if the files inside the "Characters" folder but not the folder.
Start "The Sims 2" and load your custom neighbourhood.
Create a new family and move them into a lot. It can be an empty lot or a house. Enter the lot.
Open the console by holding down "Shift", "Control" and "C" at the same time. In the text field, enter "boolProp testingCheatsEnabled true" to start cheat mode.
Shift-click on the mailbox and select "Neighborhood" then "DBG - FORCE Create All NPCs." Select "Yes" and then select "Yes" or "No" when asked if you want to use all skin tones. As the NPCs generate, a pop-up will appear in the top-right corner of the screen telling you that the NPC has been created. When the process is complete a pop-up should appear to let you know.
Shift-click the mailbox again. Select "Neighborhood" then "DBG - FORCE create all Townies." Select "Townies" or "Downtownies" (if you have Nightlife installed).The tooltip pop-up in the top-right corner will keep a running tally of the Townies created. The message "Done making all townies" will appear when the process is complete. Repeat for Downtownies if you want.
Exit cheat mode by bringing up the console again (Shift-Ctrl-C) and typing "boolprop testingcheatsenabled false." Save the game. You can now play this neighbourhood or quit.
James A. Sausville's NPC Replacer program is another easy-to-use out-of-game way to alter the appearance of your NPCs. See the tutorials at Mod the Sims for ways to use SimPE to alter your NPCs' appearances out-of-game. You need to register with Mod the Sims to download things from the site. The registration is free.
Always back up your neighbourhood before making changes if you don't want to lose those characters. Using the boolprop cheat can cause problems in your game as a whole. Always exit testing mode as soon as you have completed your changes.