load the szs in switch toolbox and then don't double click (preferably) the BMD/BDL, right click it and there should be an export raw data option, press it and then load that into blender 2.79 with blemd
for the szs, you need to unpack the filesystem in dolphin, so right click the rom, go to properties, filesystem, right click the disc and choose either extract data or extract entire disk
for the szs, you need to unpack the filesystem in dolphin, so right click the rom, go to properties, filesystem, right click the disc and choose either extract data or extract entire disk