Go to the build mode and look for the icon shaped like a hammer, click on it and then on the section of wall you want to delete (make sure it is highlighted) click on it, and it should disappear.
Chat with our AI personalities
You make your sims get really angry, then when your sim is very angry it will knock down all the walls either by punching it or kicking it. To make them angry, make them go to the bathroom 10 times in a row.
while in biuld mode, click the wall icon (doesn't matter which one)and hold ctrl. Then drag your mouse cursor across the wall as if you were putting one up, while holding ctrl. I said that just in case i confused a little.
To delete a wall in the sims three select the build icon and then select walls. Select the hammer icon and click and drag the wall you want to delete. If it doesn't work hold control and click at the same time.
You go on to build mood and basically build a wall but hold down control at the same time and they will disappear and you'll get money.
Click on the wall tool (like you're about to build a wall), then hold ctrl button while you click on the walls you want to remove. You'll see the pointer changing