Usually, a lights 3D model is a specialized asset for lighting fixtures (e.g., lamps, studio lights), while a SketchUp 3D model is any 3D object created or editable in the SketchUp software.
Lights 3D models focus on functional or decorative lighting elements, used to add illumination to 3D scenes. SketchUp 3D models are broader—covering buildings, furniture, even lights—designed with SketchUp’s user-friendly tools, common in architecture and interior design.
For SketchUp projects, importing pre-made lights 3D models saves time vs. modeling fixtures yourself.