On broad rule: it depends on your local law and how they apply to you within the third party that "feels damaged" by your copy-product.
Generally speaking the US is the most strict; a notorious recent case is Nintendo suing and obtain a piracy settlement with a couple in Arizona ( ref) of about 12$million.
Such laws do mostly "apply" when the copyright holder feel damaged by your work, there are companies who are more strict (like Nintendo, which is basically the wrost not giving a shit even for fan's made free game) and other who are pretty much lasseiz faire ("let people do": less inclined to sue fans) like Valve who are notoriously know for even working with the mod community fan/game to growth in their own product.
It's a complicated alchemy made by local laws, copyright holder, economic situation (starving companies are known to get more aggressive, while companies who shut down are pretty much inactive into protecting their IP)
TL;DR: There are lot of developer/designer/artist: don't feed big and deaf companies: get together with other people and build your own IP/arts/stuff!