Place each sim household into the Population Queue. Then, right before export I can remove my library folder, restart my game, and save just the sims I need to import into the world I'm finishing using the Porter Mod by Twallen. I often do community projects where other simmers donate sims, this way I can keep them all separated for each world I'm working on. I made this world to keep sim households while I build a world. It gives a simple step-by-step introduction to populating worlds with mods, without any additional prattle. This section was written by the wonderful Auntielynds.

Players can find the latest version of all the NRaas mods at Basic Method This tutorial assumes readers understand how to install and manage custom content. Even so, it is a sensible precaution to back up the world before attempting this. Suffice to say, worlds populated with this method should carry warnings, but appear to be safe if certain rules are followed. These testers have now maintained working worlds across four or five generations without any corruption that is apparent to end users. However, creators should bear in mind the pool of testers has been small and largely non-technical. Testing to date demonstrates that these Sims will be installed with the world file, and will act just as the premade Sims in Sunset Valley or Twinbrook. It is possible, using a combination of mods and EA debug commands, to add Sims to custom worlds using Edit-In-Game in the Create-A-World tool (CAW).

Please check out the discussion page for less substantiated research and areas to look into. 3.5 Step Four: Reset motives before saving.3.4 Step Three: How to add premade Sims.3.2 Step One: Using the Make Sim command in Edit-In-Game.

Sims 3 custom worlds not showing up