This process in architecture is called massing.
Massing refers to the conceptual and preliminary design phase where architects explore the overall form, volume, and spatial organization of a building. It involves studying the arrangement of major programmatic elements—like the garage, living room, and bedrooms in your design—using basic shapes and volumes to understand how they relate to each other in terms of scale, proportion, and hierarchy. Massing helps architects establish a building's footprint, height, and spatial flow before refining details, often using tools like Rhino or physical models to visualize and iterate on the design.
It’s a critical step in balancing functionality, aesthetics, and site context.