I’m interested in this also.
I haven’t tested it thoroughly on complex, realistic scenes but the (not yet well documented) screen space curvature post process effect borrowed from Blender could provide an approximation of what you’re seeking. I think it works best on stylised scenes and for accentuating model topology when modelling in Blender, but applied with subtle settings to a realistic scene, it could provide a nice, subtle rounded effect to sharp edges. Not physically accurate I know, but relatively cheap and easy.