Do I understand you correctly that you are looking for a way to view web scenes without a web browser, but with a "standalone" desktop application?
If so, I am sorry to disappoint you on this: At the moment the CityEngine Web Viewer is the only application reading .3ws, and it is designed as a web-application that runs only on browsers.
The offline version of the Web Viewer (as it is available in CityEngine as well) is basically the same web-based application, but with no dependencies on online ressources, means it works also without internet connection. However it still needs a browser to run in.