What are free tools for start primitives 3D models?

Free tools for creating primitive 3D models include Blender (open-source), Tinkercad (browser-based), and SketchUp Free—all offer built-in basic shapes (cubes, spheres, cylinders) and simple editing. Blender is versatile for all skill levels, with modifiers to tweak primitives; Tinkercad uses drag-and-drop for quick, intuitive designs; SketchUp Free excels at architectural or object primitives with easy scaling. For beginners, start with Tinkercad—it’s user-friendly. If you want to grow into advanced features, Blender is a strong choice.