An absolute mid-air pointing technique requires a preprocess called registration that makes the system remember the 3D positions and types of objects in advance. Previous studies have simply assumed that the information is already available because it requires a cumbersome process performed by an expert in a carefully calibrated environment. We introduce Overthere, which allows the user to intuitively register the objects in a smart environment by pointing to each target object a few times. To ensure accurate and coherent pointing gestures made by the user regardless of individual differences between them, we performed a user study and identified a desirable gesture motion for this purpose. In addition, we provide the user with various feedback to help them understand the current registration progress and adhere to required conditions, which will lead to accurate registration results. The user studies show that Overthere is sufficiently intuitive to be used by ordinary people.