Your vertex-heavy 3D model lags in SketchUp usually because of too many vertices (overly detailed geometry), unoptimized components, or insufficient hardware resources (RAM/GPU).
Too many vertices force SketchUp to render more data per frame—even small dense details add up. Unoptimized elements (like ungrouped faces or high-poly parts) increase processing load without purpose. Underpowered hardware can’t keep up with real-time display of complex models.
To fix this: Use SketchUp’s “Simplify Contours” for terrain, reduce detail in high-poly components, close unused tabs, or upgrade RAM (if under 8GB).