Is it Illegal to Use Assets from Another Game for Research Purposes?

I think there’s something about the whole legality of licensing in the EU, there was some case about it like with Autodesk licenses where they ruled that you have a right to resell licenses or something like that.
Ultimately, if it came down to it it would have to be decided by the Court, but for a lot of people even trying to fight it would be an even if you’re on the right side legally.