Proxy model

A proxy model represents a high-polygon object, such as a detailed tree, car or armchair, as a simple box, a point cloud or a low-resolution stand-in while you work. The real geometry lives in a separate file and is loaded into memory only when the render engine calculates the image. The viewport stays responsive and the scene file stays small.

Why proxies are used

In architectural visualization, landscape and context elements can easily outweigh the building itself. Add hundreds of trees, shrubs, cars and people as ordinary geometry and the modeling program slows to a crawl, with saving and opening taking minutes. With proxies you can move around the same scene comfortably, look for camera angles and keep editing. When one proxy is copied many times, the render engine usually stores it once in memory through instancing.

Practical points

Because proxy files sit outside the scene file, they must travel with the project when it moves to another computer or a render farm; otherwise objects simply vanish from the render. Keeping file paths relative to the project folder avoids that headache. Materials are usually stored with the proxy, so changing them afterwards is a little less direct than with normal geometry. For ways to lighten a SketchUp model before rendering, see SketchUp model preparation before rendering.