Creating, then posting, derivative works

[Chgowiz]

Please bear with me, as I find much copyright law completely confusing, and what constitutes 'fair use' and allowed fan art and the like.

I'm doing a series of maps for my own homebrew (no 'official publication or money making intended), based fairly completely on existing prior art (say a computer game). If I make examples of those maps available online, like in a forum like this - is that against copyright rules? Do I need to say that it's based on the original XYZ game published by ABC Co? Am I even allowed to post such things?

I don't want to break any rules, but I also appreciate the constructive criticism that I can get from a place like this.

I looked for similar discussions here, but couldn't find anything beyond the discussion about people copyrighting their own work.

Thanks.
Neurowiz

[NeonKnight]

If the map you are doing is your own version of the map, then I believe that is fair use, (Think of Anna's versions of Greyhawk, or someone else's version of Forgotten realms or Middle earth).

You did the work, and the work is based on a known entity.

However, you cannot post a copy of the original even if you claim it is not yours, as likely you do not have permission to post copies of it. You can post links to it.

[dormouse]

If it is a map done on the basis of a text description, there will be no problem.

If, however, it is a reworking of another map, there could be a problem. Whether it trangresses the copyright of the other map will be down to a legal judgement. It would certainly be safer not to post such copies. Giving the original reference will be no protection, unless the copyright owner has given permission for your map to be made available.