A CAD software might be required to create the 3D model you want to 3D print. CAD allows precise creation and customization of 3D models, ensuring they meet specific size, shape, and structural requirements. CAD software provides the necessary tools to design intricate details and ensure geometric accuracy, crucial for successful 3D printing. However, for beginners or simple projects, there are also user-friendly, free 3D modeling tools available that can serve the purpose without the complexity of full-fledged CAD programs.