Missing download link for iModel Plugin for SketchUp from this page - Create iModels (bentley.com)
Sketchup or OBJ is not listed there.
Oto, the link above was for general information on iTwin Synchronizer and how it works.
Regarding Sketchup, see this article: Supported Applications and File Formats
Jesse DringoliTechnical Support Manager, OpenFlows ProductsBentley Communities Site AdministratorBentley Systems, Inc.