Free tools for understanding polygon 3D models include Blender (open-source), MeshLab (mesh analysis), and Windows 3D Viewer (built-in).
Blender lets you view, edit, and check polygon counts with real-time previews—ideal for learning editing basics. MeshLab specializes in mesh quality: it detects gaps, overlaps, or irregularities. Windows 3D Viewer is simple for quick structure checks, no setup needed.
Beginners should start with Windows 3D Viewer (built into Windows) for ease, then try Blender’s tutorials—both are free and low-threshold for learning polygon 3D models.