IDK if the Viewer Pane is a work in progress toward an actual Quicklook like implementation or it's purpose just as an old school preview pane.
The viewer pane seems to do a decent job previewing dwgs, pdf, png, txt etc, won't seem to preview many 3D CAD file formats though .stl, .fbx, .nwd, ifc, .rva
But the side pane for a preview isn't ideal.
Will there eventually be some capability for us to have the viewer actually pop out to quicklook files with the 'Spacebar'? That's the obvious key, it's used to play, pause, audio, video in pretty much any dedicated media player or editor.
The Standalone Viewer is more suited to opening after double clicking a file, but Viewer
(pane) should pop out with a Spacebar tap and the next file should be displayed when tapping down/up arrows in the directory.
I have Quicklook Win-QL pops up a preview with spacebar but doesn't support dwgs very well, DO native solution preferred.