I'm probably really late to this having just got back from a vacation that's resulted in little-to-no internet access, but does Sonic 3D Blast on the Saturn/PC use models instead of pre-rendered sprites? I ask this because R and Jam use fully 3D models, and I played through Blast's PC edition recently having unearthed it from a box of old games (I was really surprised it still ran - and ran well - on Windows 10) and I swear Sonic and co look like models, instead of sprites. I've asked this question on another thread but got absolutely no answer, and this thread looks less dead, so hopefully I don't get banned for spam or etc.
They're pre-rendered sprites, except the Saturn special stages those are models (the PC special stages used pre-rendered sprites again).
Sonic 3D Blast on the PC uses 3D models for the actual track, but sprites for the things on the tracks. They'd be stored in /PCSONIC/BONUSx, but I have no idea what format they're in. And (while I was looking) level data appears to be in /PCSONIC/CDDATA/LEVx/, but again, no idea what format. I presume that the tileset graphics are in the MAPxx.BIN files, but this is the best view of them (MAP1C.BIN) I've been able to get.
Damn. Thanks anyway, hopefully someone'll be able to get into Blast's filesystem. I've heard it has the same (or very similar) compression system as R... on the Saturn at least.