Healing Non-Manifold Objects with Blender

Have a marginal STL you found on a community sharing site that doesn't slice well? This video shows a simple way to heal that STL and make it printable. After making this I learned that you can click (deselect) the camera icon in the boolean operation to avoid the "double whammy" of calculating the operation twice.
Update. See comment below. There is a 3D Printing toolbox add-on for Blender that makes this a little bit easier. It's not 100% reliable, though. You can always fall back to this method, which has proven very reliable.

[@GridSpace]

This will work for many objects and not for others. There are infinitely many ways meshes can be broken and non-manifold. If this isn't working for you, then your mesh likely requires a human to inspect and repair the defects.

[@OMNI_INFINITY]

Seemingly that video should have been titled: "How to make blender crash"

[@GaWoP]

I am using Blender Version 4.1.0 (4.1.0 2024-03-26) and unfortunately did not have the same luck with this particular approach. The "Self" intersect method is not longer an option. I attempted a similar workaround where I applied the modifier to the cube and used "intersect", and it appeared in the viewfinder to have similar results, but it didn't fix my manifold issues. I am saying this in hopes that this alternate approach works for others and that it was just a personal issue with my particular geometry. Another approach that did work for my geometry was the "Remesh" modifier. I used the "Voxel" approach in the remesh function with a sufficiently small mesh to grab all the fine curvature of my model. This worked, but warning that it was very memory intensive. It took me a couple iterations to find a sufficiently small resolution size such that it (1) captured all of the curves in my model and (2) didn't crash my application because of how small I was refining. Good luck out there!

[@AArmstrongC]

what if you do the boolean step with a Geonode setup?

[@electroninja0]

This worked perfectly. Thank you, savior.

[@DrPeppa]

Thanks for this, I hadn't noticed the remesh modifier before. This makes a perfect "I'm done making changes to this model and just want to print it" button lol.

[@hoenigmarkus]

You can avoid the double load time by deselecting the "Realtime" view. It is one of the 3 small buttons on the right side of the word "Boolean". If you have the "Realtime view" deselected it only loads once, when you press "Apply"

[@GridSpace]

true. and that's what I do now. thanks for the note.

[@gunsboy77]

Man, I watched dozens of videos using face orientation, solidify, shrink-wrap modifier, and a few other ways. This is the only one that worked.

[@jackkuehneman9300]

3 years later this video still helpin folks. thankyou sir!

[@roberte7606]

Perfect solution! Allowed me to print two minfigs that I've spent hours trying to fix. As always the simplest solution is the bet one - Many thanks!!!

[@connorquinn8451]

Literally a life saver! Been trying to 3d print some game models that were definitely not meant to be manifold and Cura was going nuclear lol

[@Scav-Goblin]

How do You ripp the game Models? Ive seen that there are programs, but i dont know what a good one is vs a bad one

[@connorquinn8451]

@@Scav-Goblin in my case the models were already ripped and in a google drive so I don’t really know anything about ripping them unfortunately

[@frothyground7075]

​@@Scav-Goblinstill need help with this?

[@sadwahwah]

Holy moly you're a genius, I've had so many problems making meshes in blender never once did I think of this

[@gitbse]

I've been struggling with this exact problem for so long when modeling in Blender. I'm not kidding .... this is (jokingly) life saving.

[@GoatPrint]

Thank you for this tutorial!!! I've been 3d scanning trim pieces in my truck and the output is always non manifold big pile of vertices. I had to ensure I solidifies the faces first and also made sure that materials in the modifier is set to transfer from the cube. 🎉

[@Boneappleteahee]

I kid you not I was converting a Game model into a printable 3D model and only 1, face was broken. I retried converting it many times. You just saved my computer from its first flight.

[@alfredoguzman8533]

thanks man that was so clear, easy and informative ive been watching videos learning BLENDER and so far you are the best.

[@baldeagle5297]

This is the very stl I was trying to fix. I'm making my daughter a Hobbit bookcase diorama for Christmas. You've earned another subscriber, thanks.

[@gregdavidd]

I always just open the object with Microsoft 3D builder, Import and Fix. Works every time. So quick and easy. Often Im sloppy with my own files and that fixes them too. I export my model from Blender to STL. I open the STL in 3D Builder , import, fix, save. works in Cura every time.

[@3diva01]

"What the flapjacks!" lol Great tutorial! Thank you very much!

[@miketully9905]

LOL! "Borg Cube this" Seriously I really appreciate this fix. I don't 3D print, but I make a habit of being absolutely certain that ALL my objects are completely free of any Non-Manifold issues before and after doing a Boolean operation. I often work with truly HUGE models (like a ship over a mile long), and with having people walking around in it I've found that pretty much any Non-Manifold issues, although not visible in long shots like (exterior establishing shots) renders look fine, but in comparatively close in shots (like two people walking through where a 50 foot diameter transfer tunnel intersects with a complex object that forms a part of the ship that's more than 1800 feet across) tiny Non-Manifold issues will cause artifacts twice the size of a man and be VERY apparent. Prior to finding your solution this could be a horrendously time consuming problem to fix. Thank you for posting this!

[@blunaa943]

In blenderwith your object selected hit: Tab, A, M, by Distance. Most slicers I believe also have options to repair non manifold edges

[@GridSpace]

most slicers are written in c/c++ or can incorporate 3rd party libraries that do this for them. KM is written entirely from scratch in JS to run entirely in the browser, so this is not a realistic option. WASM, if you are aware of it, is a heavy lift to achieve this goal.

[@TerranceLam]

THANK YOU! I have been importing my files into freeCAD or other programs and sometimes it worked and sometimes it didn't. This is way better and works with my own blender-created files that I create and clean up for later distribution. Much appreciate this video.

[@12setver]

Man I feel like i owe you more than just a like and sub. This is the best quick fix I've seen to date. Thank you!

[@mm2dip]

Wow!! I’ve been looking for this for ages. Thank you 🙏🏻

[@brianschmitz8056]

DUDE! You saved me HOURS of work!

[@thenerdsherpa540]

Amazing! Simple fix to such a pain in the @$$ issue. Thanks for posting this!

[@Jonathan-ex3sl]

Nice, I was trying to do this with unions but this is much better. Thank you!!

[@bouttausemyblade]

You saved my life king❤

[@jacobmaz8157]

Thank you! Didn’t work for me but this is exactly what I need to fix so I’m getting closer at least…

[@ariadnedanelle]

This turned a model that had 30 errors into a model with 106 errors. lol. I don't doubt that it works most times. But I applied it to a file that windows 3d wont even fix so i am not surprised it didn't work. I appreciate the tip though. Typically the windows "3d Builder" does a great job at fixing a few manifold issues but it struggles with really big files regardless of number of errors. But I recommend trying it if this blender method doesn't work. Though the current file I am having issues with won't fix with either of them.

[@WhiteNoisePhantom]

BLESS YOU! I had this posed figure from a game I wanted to print and this helped fix the model for printing!!!

[@themuddyrug55]

Genius. Saved me a lot of time. Thanks!

[@Cr4y7-AegisInquisitor]

I guess this only works if there are no holes in the mesh?

[@AClarke2007]

Probably check Face Normals are pointing outwards first!

[@666aisha7]

i didnt watch ur video yet but i wanna say that is very cute how u calll it healing

[@amithacohen3387]

thank you so much you saved me a ton of time with that trick. up until this point i used to remash the model to fix that broblem...

[@adoorframe9353]

Did this on a Apex legends Octane model from CGTrader. It originally had 1933 non Manifold edges. When I used this solver it went up to 12667 Non manifold edges

[@GridSpace]

it's not going to work for all models. there is no perfect or right solution for any random polygon soup.

[@ArnaudMEURET]

If you paid for this model, please take the time to point out in the comments over at CGTrader that it’s not printable, please !

[@Oidium45]

Looks like a great tool! Sadly, when adding Boolean I do not have the same options as you. There is no "solver" or "self" check box.

[@GridSpace]

Blender keeps changing their UI, so between point releases things tend to move around a lot

[@CameronKiesser]

Arrow down. There the self button is at in 3.0

[@nganpoiis8961]

Blender is the nipslip of 3d modelling software 😂. Thanks dude

[@emmanuelwhyte444]

Thank you for this straightforward demonstration. So...much...time...saved.

[@djC653]

Have you seen the 3D Printing Toolbox add-on that comes with Blender? There is a "Make Manifold" button. Now I do always turn this on but I think I've never hit that button. Maybe quicker way

[@GridSpace]

I have not. But thanks for the tip! I'll go check it out so I can recommend it to others.

[@djC653]

@@GridSpace you know how to turn it on? Edit/Preferences/Add On/ search 3d printing and check box to turn it on.

[@djC653]

oh and when in Blender just hit 'N' and it will be on right side of viewport

[@GridSpace]

It took me a minute to find the menu item once it was enabled :) I tested a couple of parts and it seems to do the trick. Definitely faster. Thanks again

[@djC653]

@@GridSpace p.s. sorry for bebunking your video :D

[@godfatheralexander]

It works only partially for me- it only separates the intersecting meshes, without actually removing anything. Help?

[@GridSpace]

the operation is a bit of a black box. unless you choose the less precise option, there are no tuning parameters. given the infinite ways in which a mesh can be non-manifold, if this isn't working fully, you have to fall back to manual editing.

[@godfatheralexander]

@@GridSpace man I'm so sorry but I didn't understand even a little bit of that. My topology is so messed up- reworking it would be too much. I made stylized hair for my character through tube paths, now everything is interconnecting and blender won't let me rig anything. ⚰

[@propdork]

Many thanx friend, solved my boolean issue due to non manifold, perfect!

[@CyricRO]

300 manifold thingies before, 500 after.. Guess it didn't work for me. Sure wish I knew how to fix this.

[@Retronize84]

Dang, I gotta try this. I learned a lot of blender to fix parts manually, this would have been a lot easier. I guess I did learn a lot on the way though.

[@uzairbukhari99]

Thank you very much! I've been stuck with an issue for days and this was so easy to fix. Thank you, God bless

[@nikgrid]

What version of Blender are you using? I'm using 2.8 or 3.00 and neither have the self tickbox.

[@GridSpace]

Since 2.9, it's hidden under a flip-down menu called "Solver Options" at the bottom of the boolean tool.

[@nikgrid]

@@GridSpace Thanks for the reply :) Under my Solver options it has Overlap threshold and then a measurement over 0.000001 mm. Any ideas? lol

[@nikgrid]

@@GridSpace Ahh I see if I change it to exact it comes up. Thanks so much

[@GridSpace]

the constant changes to the Blender interface are real head scratchers

[@tyler1234321]

thank christ bro. good work.

[@davidayoub6829]

hello, i tried to do it but the object i am healing disappeared . I would like to know what to do in this case , any advice ?

[@_sans_oo1824]

Your video saved my project!

[@GridSpace]

Glad I could help!

[@ilaimor]

there is an addon in blender mesh/print 3D print tool box

[@GridSpace]

yes, there is. I have found the "make manifold" tool that is included is generally less reliable than this method. on occasion, it does succeed where this does not.

[@Sam_North15]

you saved my life.

[@MikeTarifaArtist]

Thank you VERY MUCH ! Very straightforward method ! all others use a bunh og complicated steps..

[@GridSpace]

Great! Glad it was helpful.

[@matthewbull3688]

Help please! I found this video as it's exactly what I'm trying to fix. My issue is that when I try and select the 'cube' in Object, it isn't listed. The original cube from when blender started up.... I did try the operation by selecting my STL object... but the STL did not get repaired. So I'm not sure if it matters whether the cube or my object is selected. Any thoughts on how to get the cube to appear in the Object list?

[@gavinbruce7128]

It is possible that you added the cube while you were in edit mode. This will add the cube as part of the original mess rather than a separate object.

[@CopperStateCustomAdmin]

So, when I hit cube and after it "thinks" the object I'm healing disappears entirely, but its still on the objects menu, I just can see it any longer. Any advice for that? Ive seen no one address it.

[@GridSpace]

either you clicked the eye to hide it or you selected the wrong boolean op

[@Alloush1980]

Hi,, Thanks for the video, i have downloaded the same file exactly , and i followed your steps one by one, but unfortunately didn't work..Knowing that i am using Blender 4.0

[@YentaTheGamer]

This increased my non-manifold edges from 240 to 602 lmao

[@highervibrations4852]

when I try this with a larger Geometry the model disappears after a long calculation time, any idea what might be happening? the model is an rc shell

[@GridSpace]

this method will not turn a shell into a solid. it's meant to resolve simpler geometry errors like ones in which a face is missing or a section folds back onto itself.

[@vjponc2]

Thanks so much for this. I've been using blender for many years, and somehow this fix had slipped pass through me

[@yutverg6109]

The only thing I have understood is the ad for the soap that came before.

[@tohneyteoh]

What is ticking on "self" for?

[@gammr3227]

when i put the modifier in the object dissapears from wireframe

[@laniuschisa8779]

THANKS MAN THAT'S A BIG HELP

[@Pokych_Adams]

Thank you so much!

[@RDUBTutorial]

Did not work - some of the options are different in the boolian setting - wish there was a newer version of this tute.

[@benofalltrades]

This isn't working for me. I have the object engulfed by the cube, add the boolean modifier to the object, select intersect, self, then select the cube as object, apply and when I go back to the object and select all non-manifold veriticies it's the same as before. .

[@GridSpace]

given the infinite ways in which objects can be non-manifold, it's not guaranteed to work. but I have found it to be one of methods with the highest success rates.

[@benofalltrades]

@@GridSpace gotcha, well thanks! I'll keep this in my back pocket

[@wfpnknw32]

amazing saved me so much time!

[@jams2u786]

All the controls to perform this manifold operation not showing in my installed version. WHY?

[@GridSpace]

blender loves to change their UI with every release

[@jams2u786]

@@GridSpace Appreciate the respones. What's missing is the SELF check box. I have used the modifier to cut a box corner from another box. But without the SELF check box, how can I perform this operation to heal non-manifolds and self intersecting surfaces?

[@GridSpace]

@@jams2u786 what version are you on? I've seen it hidden under a drop down in some versions.

[@jams2u786]

@@GridSpace Version 2.83 64Bit Windows 7 64Bit

[@GridSpace]

I've been using version 2.9 recently and it has the "self" checkbox under the solver

[@tutucaman8496]

you are a life saver man

[@OZITOMAE]

this didn't work for me unfortunately. when i throw it into a slicer, it comes up still broken and can't be fixed

[@ijam4ever]

sounds amazing!!! but even disabling the Render my blender Crashes! :( it stays iddle on Apply and then crashes. is any solution to this?

[@GridSpace]

if blender is crashing, I'm going to guess your model has a lot of vertices.

[@silver2331]

Mine crashes too 😭

[@OnshapeInc]

Did someone say 🥞's? Great video, thanks!

[@darkscorpion6534]

Incredible tip brother.

[@endorfinsky]

I don't understand a damn thing, but it's very interesting

[@osmanender]

You are The Man👊

[@paxtontuncel4458]

Thanks Man! Helped a lot! 👍

[@PaulDominguez]

One of these days, I need to learn Blender

[@GridSpace]

Me, too :) This is the equivalent of spackling drywall. It's the lowest rung on the Blender skill ladder.

[@humangarbage3386]

It worked thank you!

[@ok...1009]

YOU ARE AMAZING! THANK UU SOOOOOOOOOOO MUCH! You dont have any idea how you help me

[@janaathanand3243]

Will this fix bad geometry data error while printing?

[@GridSpace]

that's more of a slicer question

[@KunaiMelee]

Thank you for the tutorial

[@manjunathbadiger2739]

Thank you so much for 👍👍

[@spinnt]

There is another solution. Import the model into fusion 360 and turn it into a mesh. Then export that file as an stl and it will be manifold.

[@cesareduardoangulosolis126]

Broh! Really Thanks

[@444guns]

thanks alot for the video

[@endcreepted4228]

Thanks a lot!

[@davidvasquez6664]

so I followed what you did bro and it deleted the whole model and left 1 vertice. Did i do something wrong : (

[@GridSpace]

without seeing the model, it's impossible to tell

[@My2Cents1]

Didn't work. 😔All the intersecting walls and objects are still there. All this did was slice all the objects at the lines of intersection. And it took my computer 1 hour to add the cube to the boolean operation, and another hour to apply. I hate my life.

[@TBjunk25]

Open the file in blender, go to edit mode, select all by trait, interior faces : go to face, and solidify faces. Fixed my project entirely.

[@Rippeee]

Thank you!

[@rafhamine1792]

Thank you, sir!!

[@JeremieDeWitt]

i try this and blender keeps crashing on me :/

[@Wee-WorldMiniaturesandProps]

Mine doesnt have that "self" option...or i just dont know how to access it

[@GridSpace]

Blender keeps changing the UI. What version are you on?

[@Wee-WorldMiniaturesandProps]

@@GridSpace i think i have 2.82 and 2.83

[@Wee-WorldMiniaturesandProps]

Is there any way i could send the model and have you take a look? I really want to print it, but i cant fix the issues

[@GridSpace]

@@Wee-WorldMiniaturesandProps sure. can you hop no the Discord server and DM it to me? discord.com/invite/suyCCgr

[@charleyedwards2121]

great one

[@waylanger]

that didn't work at all for me. the object just dissapeared. like it had been reduced to 1 pixel

[@GridSpace]

if you miss any of the steps or settings, that might happen. also, if the object is just an open shell, results are unpredictable.

[@fotisxevgenis]

My Non-Manifolds actually doubled after trying to do that xD xD

[@rickybobbyracing9106]

Which it worked for me on an M18 battery adapter, but did not. Still thanks for doing the video.

[@tiozaod.105]

work. Thank you bro.

[@CalebLoera]

Very smart

[@tommypietch6798]

i love you so much ty

[@gianmariostuppello4017]

Thankssssss

[@virgilplays]

didnt work at all. still had non manifold edges and repairing them still fucked up my model

[@GridSpace]

given the literally infinite ways a mesh can be non-manifold and the limitations of sw to tackle np problems, this fails to surprise

[@Slimyn]

i twitched a bit when you didnt delete the default cube

[@TTTristan1]

This just doesn't work for my model...

[@GridSpace]

It can't work for all models. There are infinitely many way to be non-manifold. Most have no path to one "correct" solution.

[@3dmodeling101]

This video explains 7 different non-manifold issues and how to fix them all. See kzbin.info/www/bejne/bWnKqnduareFoNE