I worked a lot on an editor for 4/5th Gen but I doubt there will ever be a working editor. (In other words. There isn't any "in the works") There isn't enough known about the bmd-format but also
yeah i found out how to do that, it required some disassembly but it turns out that data is actually lz77 compressed in the arm9.bin file somewhere, i'll dump it soon and share it with you.
unfortunately the data isn't repointable, it's decompressed into static memory that's present for the entire game (the data is loaded even before the intro/title screen) and the address is hard coded into the game in multiple areas. i can tell you where its loaded in memory while running and i can tell you how to edit the data, recompress it, and replace it in the arm9.bin file though. give me a couple days though cuz i haven't touched anything pokemon related in like a month due to school and getting a job for the summer and other crap.
He hasn't answered eversince (last login in january). I still wonder how he found out...
But there's another way to edit maps. You can load them through my tools. Import them in 3ds max. And then use nintendos official tools to convert them back. (use G3DCVTR as keyword when searching)
The connection between mesh and textures however is hardcoded.
Wow. How do you know?