I’ve read the policy regarding weapons but I’m still a bit confused. Would a 3d printed master sword be considered a “realistic” weapon or would that pass under the fantasy weapons umbrella? Any help would be appreciated.

It would depend on what it looked like (is a "master" sword something specific? sometimes my finger misses the pulse of all the fantasy going). How it was produced is irrelevant. 

The master sword is the sword that Link uses / finds in all the Zelda games.  

As for what passes / doesn't pass the weapons policy at GenCon - its very lax and has traditionally been mostly used to stop people from brandishing weapons or using props inappropriately.  If its a 3d printed version of teh sword you will *probably* be fine, but I'd try emailing GenCon specifically first.  

Did you make the file yourself or did you get it somewhere like thingiverse, and how did it turn out? (asking for...me.  I'm asking for me.)

I've been really interested in making a 3D printed Master Sword as well. Not for use at cons, just to display in our game room.

But to answer your question, let's say your sword looks like this:

You are probably ok as it looks nice, but not "real" to the naked eye.

Now if your sword looks like this:

[img]https://static.independent.co.uk/s3fs-public/thumbnails/image/2014/03/04/08/master-sword.jpg?width=1368&height=912&fit=bounds&format=pjpg&auto=webp&quality=70[/img]

(The preview shows up, but when i post, the photo does not for some reason. Can't figure it out)

That's a no go.

The more "toy-like" the better.
 

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