Game guide:Fog emitter

Fog Emitter is a special object in The Sims 3 that can be used to create special effects in the game, such as steam, waterfall, and so on. It was first introduced and only available in Ambitions, but as of patch 1.42, the fog emitter was made available for base game. The fog emitter appears under buyDebug Buy mode category. To access, use  and   cheats. The object will be available under miscellaneous debug section it appears as a floating blue sphere.

To use the fog emitter, ctrl+shift+click at the object to bring up the options. The players can set visual effect, disable visual effect, or add the ability to add triggers and activated behaviors (as part of tomb building interactions). Choosing the "set visual effect" interaction will bring up a window. There is no list to display, so the players are expected to have known what effect to use. There have been tens of thousands of effects in all. The list of fog emitter codes for Island Paradise is available for download in .txt file, credits to Simified. All effects don't have descriptions, as the names are all self-explanatory. For example, waterfall_1_short is used for waterfall effect, but it's unclear which waterfall effect it will display, as there are many other waterfall effects.

There's a mod at ModTheSims by Buckley that enables the player to shift the fog emitter up and down, which allows more flexibility for effect creations.

Also something to note is that the effect will stay in place even when the lot using the fog emitter is exported and shared, so effects will not be lost or improperly missing when other players use the shared lots.