how do you disable this?
You can disable the simulation environment by disabling the XR Simulation loader in XR Plug-in Management.
Also, there are less “crappy” environments available if you still wish to test AR functionality in the Editor. Go to Window > XR > AR Foundation > XR Environment to open the XR Environment window. There, you can view the XR environments available in your project. This lightweight default environment is the only one included in the package, but there are some really nice ones! Click the drop-down in the overlay UI and select Install sample environments. This will download and import the more detailed environments which will be added to your Assets folder.
You will be prompted with the standard .unitypackage importer where you can select which assets you wish to include. Bear in mind that the environments share dependencies, so we recommend that you bring in everything at once.
but do these virtual ar environments work in editor preview?
Just a note that in 1.0.3 disabling simulation environment is grayed out.
That’s surprising. I don’t think this UI is supposed to be disabled except in Play Mode.
Yes, those environments are part of the XR Simulation feature, and will replace the default environment you are seeing that is just a pair of planes and an image marker.