alt.hn

4/9/2026 at 4:58:46 PM

Unfolder for Mac – A 3D model unfolding tool for creating papercraft

 https://www.unfolder.app/

by codazoda

4/9/2026 at 7:36:15 PM

I like the clean design of the landing page. I downloaded it and started the app and it needs an OBJ file to even do anything, so I wasn't able to play with it at all.

It would be cool if it included sample OBJ files to entice me to find my own later. Otherwise I feel like I just hit a wall immediately in the app will probably not try it again.

by allenu

4/9/2026 at 8:35:24 PM

The way I tested was search Thingiverse for "angular" and download an STL, then convert it online to an OBJ on the first search result for "stl to obj"

Specifically I tried this rook from this chess set. https://www.thingiverse.com/thing:5994219/files

Sadly, some of the crenelations on top of it are just cubes with 2 sides missing that would be impossible to attach to the folded up rook. I imagine there is a ton of loss between a file for a 3D printer, a random convert to Obj with no settings, and this net maker, so I'm not unsympathetic to the problem. It's just that this is a printout that would not be foldable into something useful.

by 1-more

4/9/2026 at 6:42:27 PM

So, like Pepakura? https://pepakura.tamasoft.co.jp/pepakura_designer/

by dnpls

4/9/2026 at 8:21:28 PM

So weird for me to see this popup now on HN as I happened to dig through an old downloads folder a few minutes ago and saw an install file for Pepakura (13/11/2014), and wondered where that sort of thing had ended up... .

by detritus

4/9/2026 at 9:13:26 PM

But for Mac! I fonder the difference of the free and paid version through.

by aziaziazi

4/9/2026 at 10:45:26 PM

You can put "for Mac" in a turd and it'll reach front page in a day.

by fabianmg

4/9/2026 at 11:23:46 PM

Doubly so if the app looks like it works well and would be interesting to HN readers!

by khazhoux

4/9/2026 at 7:42:14 PM

No!

This one is called Unfolder, it's a different app, made by a different person, etc...

More than one app per category can exist, and that's good!

by moralestapia

4/10/2026 at 7:24:37 AM

Sure, but it's like Pepakura. And that's a valuable piece of information for people who don't run MacOS.

by KeplerBoy

4/10/2026 at 3:44:34 AM

For a look at someone solving a harder version of this problem with stretchy fabric deformation, check out pandafold.app

Admittedly an unconventional audience but its a curious problem space. Pepakura as mentioned here does this very well. The author of this software looks to be familiar with it

by adkaplan

4/10/2026 at 5:56:53 AM

I found the idea very interesting but put off a little bit by the various details such as face normals etc (have limited knowledge of the topic). Here are few ideas to increase adoption:

- Sample files

- A video of end-to-end process of creating a basic model (perhaps something more complex than a cube) from 3d design to finished artefact.

- Support for STL

- Built-in option to adjust (reduce) face counts

by cagz

4/10/2026 at 7:07:11 AM

I don't have an usecase, I don't own a printer even. But this is actually a good piece of software - it seems non-trivial from algorithmic point of view, UX is also well polished. Kudos to authors.

by alfanick

4/10/2026 at 7:14:03 AM

Same — as someone building macOS utilities I have a soft spot for indie apps that tackle genuinely hard algorithmic problems and still manage to ship a clean UI. The gap between "technically interesting" and "actually usable by non-experts" is huge, and it looks like they've bridged it well here.

by lzhgusapp

4/10/2026 at 5:20:28 AM

Just a suggestion: have an example obj object, or several, loaded up. It will sound nuts to you, but I probably won't find one and will just unload the app when I need space.

by joeevans1000

4/10/2026 at 1:00:31 AM

What's the usual production method for the final model?

Do you need cardstock and a cricut machine? Or a laser cutter?

How do you align artwork on the object?

by avidiax

4/10/2026 at 7:24:27 AM

Print it, use scissors and glue.

by alfanick

4/9/2026 at 10:09:55 PM

I wrote something like this for windows 20 years ago, a friend of mine used it to make some cutout models for an art exhibition.

It's an interesting problem to try to solve. Anything but the simplest model requires more than one cutout, which you then (in my app at least) have to position by hand onto sheets of paper for printing. Performing the unfold to minimise the number of separate sections was not something I even attempted.

by davebranton

4/10/2026 at 5:07:25 AM

Hmm couldn't find any pictures of actual results from using this?

by stbtrax

4/10/2026 at 8:46:07 AM

I didn't use this app, but I did happen to make a paper moai mask recently using a pattern purchased from etsy.

https://ibb.co/BHcG4BkB

by phrotoma

4/9/2026 at 9:06:59 PM

Oooo this might be useful for doing geometry unwrapping for laser cutting

by KaiserPro

4/9/2026 at 8:15:02 PM

This is great - reminds me of the golden age of cool little MacOS apps

by constantlm

4/10/2026 at 1:37:00 AM

It would be cool if this used ModelIO to do the 3D model loading. It supports a ton of formats which would ease the workflow of asset import.

You’d get STL, Alembic, USD, PLY support in addition to the OBJ.

by dagmx

4/9/2026 at 8:58:29 PM

This is really cool.

As someone who is not into papercraft I'm intrigued, but it feels like it's not for me. If the app was advertised as having a small selection of simple models to get started with, people in my position might be more interested in trying it out.

by Aurornis

4/9/2026 at 10:52:05 PM

Why is this not a web page?

by shooshx

4/9/2026 at 9:45:28 PM

I remember something like this was huge for rc planes 10-20 years ago as you could then make a plane out of thin bendable foam

You'd make a 3D model from 3-views then use something like this to unfold it

by ge96

4/9/2026 at 9:58:42 PM

You're thinking of the same app i used to use! I think it was a Japanese app called Papakura? It's what helped me learn 3d modeling back in the day

by shahar2k

4/9/2026 at 10:25:49 PM

Beautiful landing page. I wonder if it uses the OCCT unfolding algorithms or something similar under the hood?

by plumeria

4/9/2026 at 11:55:26 PM

Slightly unrelated: are the OCCT unfolding components a paid add on or included in the open source distribution?

by wizzledonker

4/9/2026 at 9:44:22 PM

Unfolder? But I barely even know her! Jk, awesome project tho! Makes me wanna make cool packaging for products

by matzie

4/9/2026 at 10:02:31 PM

What a fantastic idea. Developers who enable others to create art are artists in their own right!

by hybirdss

4/9/2026 at 10:15:34 PM

Good artists enable others, great artists enable only Apple users.

by amelius

4/9/2026 at 11:09:10 PM

This is lovely and very slick, but you can get equivalent results for $0 with Blender and Export Paper Model.

That has the benefit of letting you create/edit/export the model in a single application instance in a single workflow that is easy with practice.

by MengerSponge

4/10/2026 at 6:40:02 AM

I will explore your suggestion, and I love Blender.

But that "easy with practice." does a lot of lifting here.

Though that practice-with-Blender then opens up so many possibilities in the 3D space it is ridiculous. Take the time to learn Blender people!

by _carbyau_

4/10/2026 at 8:30:36 AM

[dead]

by techpulse_x

4/9/2026 at 6:37:51 PM

Mac only. Is there any reason this couldn't be a web app? And seems pretty restrictive to just have one platform, a desktop Mac.

by ElijahLynn

4/9/2026 at 7:48:08 PM

If I built a Mac app, the reason would be that I use a Mac, as do a lot of other people, and native apps are a lot more pleasant than non-native apps. I don't really understand why it's "restrictive"? There is no restriction happening.

by dwb

4/9/2026 at 8:29:02 PM

The author had to decide between making something excellent for some people or mediocre for everyone, and chose the former

by hbn

4/9/2026 at 9:15:33 PM

You may use Pepakura if you’re running windows. Not sure if a web or linux alternative exist.

by aziaziazi

4/9/2026 at 7:58:40 PM

The same could be said about pretty much _any_ software.

by joemi

4/9/2026 at 11:05:33 PM

You can vibe code an app like this, relying on OBJ import (no editing apart from cutting/opening constraints), in possibly half a day.

If you doubt me, take, me up on it.

Sure, I have 35 years of experiences writing computer graphics code but I am certain I would just need to provide functional description input to Claude or Codex for this.

Zero architecture or deep 3D know-how.

The only challenge/interesting part is what happens with non-planar polygons (>3 vertices). I.e. deciding if they can be unrolled (approximated with a cylindrical or conical surface enough to 'work' when cut from paper that does not stretch).

You can alleviate this problem completely by always triangulating befor calculating any unfolding solution ofc (and get zero curved surfaces in the resulting paper model thusly).

The rest is rather trivial.

I'm not saying this isn't great, I just don't understand how you could ask people to pay for it, in early 2026.

by virtualritz

4/10/2026 at 12:36:58 AM

I can tell that is not trivial. I like to design papercrafts with my kids, and I use Blender but always wanted something on par with Pepakura but for Linux, so I decided to use Claude to build something similar. Furthermore, I started suggesting the Java/JavaFX stack because it is easier for me than JS, but I couldn't even create an STL viewer, so I let Claude decide the tech stack. It chose web/react/etc. (no surprise), the STL was loaded and presented as expected, the unfolding process was harder, and finally I gave up. Claude couldn't figure out by itself the best algorithm; the results were always wrong, and unfolding was just the first feature I wanted. My conclusion is that this is not the kind of application that can be easily resolved with vibecoding; the approach must be different, maybe AI assisting specific building parts to someone who knows exactly how the result should be with low-level detail.

by ndrsgrrr

4/10/2026 at 6:50:19 AM

You should really try vibe coding a nontrivial 3D app before you die on this particular hill. LLMs are still really bad at spatial reasoning and coordinate systems. Like, painfully bad.

by swiftcoder

4/9/2026 at 11:21:36 PM

No you should vibe code an app like this and prove yourself. Then see if people actually use it.

by teaearlgraycold

4/10/2026 at 7:33:34 AM

> If you doubt me, take, me up on it.

Given your confidence and the seemingly small amount of time you think it will take, this seems like something you should be proving rather than expecting others to do so.

by supermatt