There are ways of doing this but they need to be implemented by Epic, the AR SDK developers (Google, Apple) or a third-party plugin developer. In the case of Unity, their ARKit plugin includes a remote that allows you to stream the camera and ARKit data to a desktop computer running the project in the Unity editor. I’ve used this on Mac OS but I believe it’s supposed to work on Windows too. We are now developing using UE4 and it’s been a pain to have to build to the device each time we want to test something. As a workaround I’m detecting if the project is running on PIE and then spawning a virtual room geometry in the scene and using standard ray traces. At least it is good enough for testing interaction logic. I’m sure a solution will come in the near future for UE4.