# Are there any shapes that a 3d printer can't print? **URL:** \ **Category:** Factual Questions\ **Created:** [October 23, 2013, 10:47am UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018 "2013-10-23T10:47:10Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [October 23, 2013, 5:20pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/21 "2013-10-23T17:20:07Z")
Sounds like the powder-based printer mentioned in \*\*Folly’s \*\*post #16 could handle this, but: Is a linked chain a significant challenge for a 3d printer? Or was it once a challenge for the early models? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 23, 2013, 7:50pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/22 "2013-10-23T19:50:26Z")
> [@bordelond](#): > > Sounds like the powder-based printer mentioned in \*\*Folly’s \*\*post #16 could handle this, but: > > Is a linked chain a significant challenge for a 3d printer? Or was it once a challenge for the early models? It could be done if each link could be supported separately from the others so they don’t touch. It’s not really a practical use for a 3D printer though. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [October 23, 2013, 7:51pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/23 "2013-10-23T19:51:19Z")
> [@bordelond](#): > > Sounds like the powder-based printer mentioned in \*\*Folly’s \*\*post #16 could handle this, but: > > Is a linked chain a significant challenge for a 3d printer? Or was it once a challenge for the early models? Not really, you just need enough ability to handle overhangs to print open loops. Most cheap hobby printers can print interlocked objects. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [October 23, 2013, 8:06pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/24 "2013-10-23T20:06:56Z")
What about a true Menger sponge? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 23, 2013, 8:26pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/25 "2013-10-23T20:26:16Z")
> [@Saint\_Cad](#): > > What about a true Menger sponge? What is a “true” [Menger sponge?](http://en.wikipedia.org/wiki/Menger_sponge) If you mean one composed of infinite iterations, then I agree. But for some finite number of iterations, it ought to work just fine, right up to the limit of resolution of the printer. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [October 23, 2013, 8:35pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/26 "2013-10-23T20:35:57Z")
> [@Folly](#): > > It also depends on the type of 3d printer. The large (expensive) Selective Laser Sintering machines would not have a problem as the layers are built up by in layers of powder. So you have the powder there to support the structures that are temporarily ‘floating’. 3D printing tech may have changed since I first saw it; if you tried to print an object that was completely enclosed within another one (say, a ball inside a sphere to make a rattle), even if you could print the interior ball resting on the bottom of the larger sphere, wouldn’t the space between them (and the interior of the inner ball) be filled with the unused fusable printing material? ---
**Author:** ![Folly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folly/32/3219_2.png) [@Folly](https://boards.straightdope.com/u/Folly)\ **Post date:** [October 23, 2013, 8:44pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/27 "2013-10-23T20:44:13Z")
> [@Ethilrist](#): > > 3D printing tech may have changed since I first saw it; if you tried to print an object that was completely enclosed within another one (say, a ball inside a sphere to make a rattle), even if you could print the interior ball resting on the bottom of the larger sphere, wouldn’t the space between them (and the interior of the inner ball) be filled with the unused fusable printing material? It’s been 13 years or so since I last had access to one, but yep I think you’re right. A rattle would defeat it without further modification. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [October 23, 2013, 8:49pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/28 "2013-10-23T20:49:41Z")
> [@Folly](#): > > A rattle would defeat it without further modification. This would defeat every 3D printing system I’m aware of, ignoring “cheats” like making the ball-container connection so weak you can shake it apart. The usual solution to this case (and a lot of others where the whole object is “unprintable”)would be to make the “container” in two pieces which snap or screw together. “Some assembly required” printing can probably print nearly anything, but likely violates the OP’s intent. ---
**Author:** ![Folly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folly/32/3219_2.png) [@Folly](https://boards.straightdope.com/u/Folly)\ **Post date:** [October 23, 2013, 8:55pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/29 "2013-10-23T20:55:02Z")
Well there we go then as an answer to the OP! 🙂 a rattle! ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 23, 2013, 9:08pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/30 "2013-10-23T21:08:27Z")
We have one in the office (for some reason). You can add some scaffolding around portions of objects that are floating in the air. Sort of like a “sprue” used in molded parts. Then just break it off when it’s finished. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 23, 2013, 9:17pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/31 "2013-10-23T21:17:44Z")
You could also make a very small hole in the outer shell, to drain the excess powder out of. ---
**Author:** ![eltro102](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@eltro102](https://boards.straightdope.com/u/eltro102)\ **Post date:** [October 23, 2013, 9:32pm UTC](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018/32 "2013-10-23T21:32:17Z")
the 3d printer could first make a hemisphere and then possibly form a droplet of its resin and drop that from the nozzle so that it hardens enough not to adhere to the hemisphere already formed and then build the rest of the sphere on that [Previous page](https://boards.straightdope.com/t/are-there-any-shapes-that-a-3d-printer-cant-print/672018.md?page=1)