I actually don't know what the problem is, whether it's a misconfiguration in their MTLs or something TG is doing wrong or what. As you should well know OBJ is not a "standard". There is no one specification or implementation. I do think that since we already have an Xfrog "compatibility option" that if they're doing something specific that we don't want to be a general expectation of the OBJ reader, we could implement it for the Xfrog compatibility mode. I'll look into it.
Update: Cinema 4D doesn't even load textures for that object at all. MODO warns that textures can't be found but prompts to locate at least one, which I did, and still the flower comes in without alpha. This does not seem to be a TG-specific issue. Please direct complaints to Xfrog, their models are broken.
- Oshyan