I’ve already watched that video. Not what I’m looking for.
First thing is, I don’t have the files (in R21) at the very beginning that he’s referencing. The folder ‘materialpreview’ only has matprev_env.hdr file in there. Second, the video only addresses changing the shape of the object, not its reflection.
The rest of your explanation seems to suggest I’m trying to put the HDR within my file. That’s not what I’m trying to achieve.
My goal, is on any Material previews that are in the dialog boxes (not within the scene itself). I don’t want to have the checkered studio with studio lighting environment, but I want the flat striped background with outdoor trees reflection. This is what was in previous versions. It’s also what is shown the video tutorial you recommended.
Since the file ‘matprev_env.hdr’ is still provided with R21 in the materialpreview, I would hope there would be a way to use it.
The studio lighting preview and an outdoor environment give entirely different representations of Material previews.