Before the geometry hits your screen, you use a slider to reduce the polygon count (e.g., from 1,000,000 to 50,000) while watching a live preview.
Skimp is a professional extension designed to optimize SketchUp performance by simplifying high-polygon models and enabling fast importing of formats like FBX and OBJ. The plugin, which offers a pre-import simplification feature to prevent crashes, is available for purchase and free trial directly from the developer. Explore options and download on the official Skimp website . Must Have SketchUp Extension - Reduce Model Size with Skimp
Instead, consider purchasing a legitimate license for the Skimp plugin or exploring free alternatives that can provide similar functionality.