Which function in a modeling program allows you to zoom in and out?

The function that allows you to zoom in and out in a modeling program is accomplished by holding down the mouse wheel. This action typically enables a smooth and continuous zooming effect, allowing users to focus on specific areas of the model or to get a broader overview. When you hold down the mouse wheel and move the mouse, it can manipulate the view, facilitating a more interactive and precise examination of the design.

While the other options might seem plausible in different contexts—such as the possibility of using the scroll wheel for zooming or double-clicking to reset views—they do not provide the same level of control or functionality as holding down the mouse wheel. This method promotes a more versatile approach to navigating through 3D models, which is essential for effective visualization and editing in BIM modeling tasks.