No subscription needed beyond your SketchUp Pro 2016 license (though you need a Trimble account).
The engine became much smarter at snapping to points, making precise modeling faster.
Models downloaded directly as native 2016 files — no conversion hassle.
While the 3D Warehouse is a web-based service, SketchUp Pro 2016 featured deep integration that allowed users to access this library directly within the software interface.
Before downloading, look at the file size. High-polygon models can slow down SketchUp 2016 significantly.
Pro users gained better control over multi-layered PDF exports and enhanced dimensions.