Well ... that nicely complicates matters.Thanks~
The raw drawings are from project team. Another engineer created it. but it is openly shared among the project team. In a few months, it'll be publicly available.
If the coworker based his drawings on "raw" drawings by someone else, the coworker probably created a derivative work (a work based on an existing work). The engineer who created the raw drawings would hold the copyrights in the original drawings.
Was creating the raw drawings within the scope of the engineer's employment or outside his regular duties? Did he create them on company time with company resources at the direction of the employer?
Never mind. It seems that this requires a personal review of all facts.
Written agreements would have been helpful prior to the start of the project.