So I run a small hobby shop, I mainly 3d print resin miniatures, accessories(unique dice, dice bottles, cryptex, terrain/set pieces, dice towers) for ttrpgs and full size props and replicas( the master sword, leviathan axe, etc.)
I've never been to gencon but have been to much smaller Cons before, Would people be interested in these kind of things if I was to get a place at the next con? Id love to gauge interest in this kind of stuff cause dropping 1000-1800 dollars on a booth and not at least making it back would be devastating as a small business.
My wife and I spent two futile hours in the vendor hall trying to find miniatures for our characters. The problem is that there are so many permutations of race, class and gender that nobody can stock them all in a small booth. Good luck finding that female Tabaxi monk with num-chuks.
Getting them 3D printed on demand would be pretty cool and I could see that being a popular booth. Nobody was offering this in the past two Gen Cons that I am aware of. Ideally, customers would have a kiosk where they configure their miniature, pay, and then watch as it gets printed (or come back later when it is done).
I'm not sure how much help I can be with respect to gauging interest. I've seen vendors at smaller cons selling 3D printed stuff (a vendor at ICON in Cedar Rapids, Iowa last month was selling just these sorts of things), but I'm not sure how well they were selling.
Normal attendance at Gen Con is around 70,000 unique visitors. So as a rough estimate, you might look at the attendance at the cons you've been to, and how much you've sold, and figure it's proportional.
But booth rental, while a big expense, is just the start of it. You'll also need to consider the cost of lodging, meals, and travel. You'll probably need someone to help out at the booth (to cover breaks at the very least), and you'll need to deal with those expenses too. Plus, the expense of producing all of the wares you'll have for sale. You'll need a lot more inventory on hand for gencon than you'd need for a small local con. Can you afford the up-front outlay, and can you afford to sit on whatever stuff doesn't sell?
I think there are some setup fees, loading dock fees, etc. associated with the convention center as well. I'm not well versed on all of that, but I have heard dealers complain about them in the past.
I hope that's helpful.
You mention you've been to smaller cons. Have you sold at these cons and how much have you sold? If you are at a con with 5,000 people and you sell $500 worth of stuff, I'd be concerned. If you are at a con with 500 people and sell $5K of stuff, I'd have a level of confidence.
If you've just attended smaller cons and have not sold, not sure I'd jump into Gencon unless you have a level of confidence from your current sales that you'd break even or turn a profit.
However.... one thing I'd be massively concerned with is selling items that fall under an IP or License. For example, the Master Sword. Nintendo is very aggressive with protecting their IPs. I'd be careful with things like that as well as other IPs and/or 3d models that might not be approved for sale by a business from the creators. Lots of eyes at Gencon to spot things like that.
I'd have to echo kevinrg about IP. The smaller cons don't see it, but once the attendance breaks 10k people start to watch. In addition to Nintendo, Paramount and Toho (Godzilla) are known to be hyper-vigilant about IP. I've seen them shut down booths during events and confiscate all the contents.
If you have been making a profit by attending other cons, then you should be ok at Gencon. Just keep in mind the demand. There was a company there a few years ago that was doing custom minis you could design and they would put your face on the mini. A year later and the people were still complaining how they didn't get what they paid for and the company seems to have disappeared.