Gnats. I hate em. I downloaded a gnat trap i found on here, and i had trouble printing it (nothing wrong with the model I found) but i toyed around with different baits for attracting gnats. What I'm using currently is old cucumber and grapes. The funnel i found however is too 'tall' for the combination of jars and bait i'm currently using. So i made this one. In openscad. And it's parametric. So others might find it useful. Adjust to your use case. Might be more useful than just as a gnat trap. Might be useless as a gnat trap. Time will tell.

enjoy.