EULAs in boxed versions are usually invalid in many European countries because you had no chance to read them before purchase. It may be different with downloaded software when you were presented with the EULA before store checkout.

However indeed it may be nearly impossible to prove that a specific mesh is a derivative of work created within the Marvelous Designer software. This is clearly a case of a nearly unenforcable EULA.

Either way you're not violating any copyright law or any other criminal law. It's a matter of civil law really. The only thing that may happen to you would be a civil lawsuit where a Korean company would be suing you in your home country... rrrrright.

Just my two cents. I am not suggesting how you should use the software ... or not.

Christian