Embedding a Web App in PowerPoint

Question

Our goal is to create a PowerPoint content add-in with the JavaScript API that embeds 3D models in PowerPoint slides. We currently support using an ActiveX control containing one of our desktop applications. We would like to utilize our lighter web-based renderer. The solution needs to support offline viewing.

We are trying two approaches, both by creating a content add-in leveraging Office JS:

1. Displaying an embedded h3d model file (compressed binary format) with our web render packaged as an Electron application
2. Displaying a html file containing the web renderer.

Questions:

• What’s the best approach to realize our goals above?
• How can we access data embedded in the ppt?
  • User drops file into a slide and sees a preview of the file in our renderer/app
• Is there a way for a JavaScript PowerPoint content add-in to access the file system or select a file in the content area?
• How can we resolve the add-in error described below?

Error:

This add-in is no longer available. Add-ins inserted during development are only available during debugging are only available during debugging from Visual Studio. Please open your project in Visual Studio and re-run your application, or deploy your add-in into a valid catalog and re-insert.

This occurs intermittently after editing the manifest.xml. We haven't been able to resolve this issue by clearing the add-ins cache or app data, restarting the development server, or by adjusting our webpack configuration.