The VG Resource

So I'm trying to rip from this game, and the files are from a gamecube game which is something ive never done before
I usually rip from ps2 or psp games.

The files for this game are all in 
.ddf
.elf
.bnr 
and .gcp 

Any idea which files most likely contain 3d models? and how do I extract them/what can I open them with?

Heres photos of the file directory

I Am Currently trying to figure this out as-well and have contacted many people and started many forums.
if any of them reply with something that helps ill put it on here for you to check out

if you just want the models use NinjaRipper but for going through the models in the game normally I have no idea
I just wanna try to find unused content.