3d printing small parts of my costume allowed?

i wanted to know what 3d printing rules are or if any. i am making all of the costume but there are some things like small accessories that i modeled in zbrush, would those count as "self made" or would that not count?

I'm guessing this would vary from con to con.

It would be best to contact the convention you're going too and ask them about their stance on 3D printed items in cosplay contests

Varies by con. Ask the organizers or judges.

Most people are fine with 3D printing, but there's a loud minority who insist that 3D printed pieces aren't "real" crafting, even if you make the model yourself.

Don't tell judges that you made the model yourself if you got it from Thingverse or whatever.

Yeah, being up front in where the model came from is important. Honestly, now-a-days contests should have a judge who is at least passingly familiar with 3D printing to be able to ask contestants the right questions about any 3D printed aspects of their costume. The method of 3D printing used (FDM vs SLA/DLP), type of printer used (done at home, at a Maker space, or purchased), the post processing done (Sanding, XTC-3D used, etc), and source of files (Model created by someone else, modified from someone else model, or created by yourself) are all questions that should come up about 3D printed props or costumes.

Just because the model was not yours and you didn't printed it at home does not mean it was a simple purchase and use, the difference between something that was carefully post processed and something that was not can be significant and can represent a lot of extra work. If they don't ask these questions at judging it could be worth bringing it up yourself so that a bunch of work you did is not totally ignored.

While I'm never going to be down with singling out a method or piece of equipment for crafting for special rules or dispensations (where do we draw the line? Embroidery machines? Cricuts? Airbrushes? Am I supposed to spin my own thread out of cat hair? Because I totally could) I've actually judged enough 3D printing to be able to confidently say that a good judge should know how to treat it. That is: exactly like every other technique from embroidery to leatherwork to worbla. First, know what goes into 3D printing a thing, second, know what finishing techniques should be used to make the piece look clean and finished, and third, balance that level of effort and skill against the parts of the costume made by other methods. And I do mean balance - I have as much against a judge who only looks at the sewn pieces and dismisses armor work as being nothing but putting glue on foam and I do against a judge who gets wowed by 3D printing but can't recognize a self-drafted pattern when they see it.

It's not enough to just say you 3D printed a piece. It has to be cleaned up, sanded and finished to get rid of the striations, and then properly painted so that the paint effects don't chip off halfway through the show. On top of that, there is an extra special mention for people who can manage the software and do their own models, with people who can download models and then modify them to be more correct or a different size also getting a nod. It's literally no different than someone using an embroidery machine knowing how to vectorize and then compile their own images into embroidery files versus someone just downloading a file versus paying someone to use their embroidery machine. If you go above and beyond, you get an extra boost of appreciation and it may push you ahead of someone else you're neck-and-neck with. If you do the middle-ground level of work, it's still impressive but comparing apples to apples would put the self-modeler ahead of you. If you do no work at the output and literally don't finish the printed piece in any way, it's no more impressive than going out and buying a hat and slapping it on your head.

Not to dismiss the "check with the contest" idea because yeah, when in doubt, but most impressive crafting techniques aren't specifically addressed in the rules. There usually aren't special rules cases for electronics, plastics, embroidery, beading, corsetry, wings, or anything else involved in cosplay, so there really shouldn't be something said for 3D printing. The fair and unbiased treatment should be at the call of the judges and directors, and if they're totally biased either for or against any one technique, call them out.

I do a fair amount of printing in my own competition costumes, and CapsuleCorp hits it on the nose. If you plan on mentioning that you used 3D printing technology in your costume to make those parts considered during judging, you need to be clear about the origins of the piece and what you did versus what you didn't. The more effort you personally put into it, the more any competent judge will care. How much you get away with also depends on your division--novices can say "someone else printed and assembled it but I painted it and mounted it to my costume" but by the time you're in advanced, you're expected to be able to model/print/finish your own stuff from scratch (unless it's so bizarrely complex you had to use industrial fabrication machinery, in which case bonus points for being awesome).