GREAT TECHNIQUE! I was using Meshmixer trying to create a void inside a model of Mjolnir for a 1/4" steel rod to reinforce it. Using Boolean Difference, no matter how I did it it screwed up the mesh...losing triangles, deforming and rounding edges - it was terrible! Did it this way and it's done simply and VERY cleanly. thank you very much , Angus! Brilliant!
That was bloody brilliant! Such a clean technique. I'll try it this weekend. Upping my Patreon $$. Should have done it sooner,, but this video finally pushed me in to realizing that your videos keep expanding my toolbox of knowledge. Keep up the great work mate.
4 years on, and this video is STILL useful. It saved me from making more holes in my walls (head bashing). I spent 4 days before finding this video and technique. All I wanted to do is embed weights into the middle of an STL file and this worked perfectly. Thank you!
This is brilliant, especially as you can modify an existing STL without sacrificing quality. No worries about math. Think of "normal" (short for normal vector) as the *direction* of a surface. So if the "normal" points northward, the flipped normal would point south; likewise, if the "normal" points outward, the flipped normal would point inward. A 3D printer - or rather, slicer, always thinks of "normal" as outward. That is why if you just flip a sphere, it becomes unprintable. Now if only I can learn how to use Meshmixer - if only I know how to drag an object to rotate it for examination! I can't even find move function in my Mac version.
OMFG this video came out at the absolutely perfect time; I have spent the morning contemplating how best to put an "air bubble" inside of an otherwise solid, high-poly model for a "bathtub toy" for my niece...and banging my head against a wall as, just like you mentioned, slapping a hole into it in Tinkercad demolished the model. So...yeah. Yaaaaaaay! :D
Thank you Angus!! I've been banging my head against the wall for hours on this, and you have such a simple solution. No more messing around with remeshing to get a boolean difference, just to have it come out all jaggy.
This is brilliant ! But I took it a step further. Hope you can follow. I was looking for a way to cut grooves or sculpt a surface but only to a precise depth. I could not find any app other than maybe Zbrush where I could easily do this. Lets imagine a hollow sphere 1/4 inch thick. It is created from 3 spheres. Where one is the outer surface and the other two are the inner, but both inners are a duplicate and set at 1/4 inch smaller than the outer. Then flip normals on one of the inner spheres. Hide the other inner one for now. Then use sculpting tools to pull the flipped surface through the outer surface. The length of pull doesn't matter as long as it breaks the outer surface. Then when all is done, combine all 3 spheres and most importantly then use make solid on the combination. The result is a surface with cut outs but not right through, and to your target depth. I hope that makes sense and its worth the effort as one can sculpt (albeit in a negative manner) without worrying about the depth of cut.
This is excellent. I haven't been using Meshmixer for this task because of the inevitable surface deformaties. Not having to verify pin placement is going to be very useful as well. Thanks for this tip.
man that is crazy and may come in REALLY handy for an upcoming project. Using pins to hold items is a great idea for various items in day to day stuff! I remember some lathes at the school i was at had cracked castings so we welded our own up and used the pins to hold the parts together for welding. Worked quite nicely!
+Maker's Muse the cracked ones were rubbish cast iron... other problem was people kept jamming the carriage against the headstock with the power feed which put tremendous force on the casting and unsurprisingly it cracked. the replacements were welded steel.
Very useful if you're primarily working with meshes. Of course if you design mostly in CAD it is better to think about your joints before you export to mesh so that you end up with clean meshes and accurate mating parts (and you are not limited to pins or other simple geometries). Don't forget to allow a tolerance for the cavities if working with fixed size pins - e.g. 4mm dowel would need ~4.2-4.3mm holes.
Hi Angus ..does this technique only work with the plane cut tool or would you be able to use the "Select,Edit, Separate (then fill the holes where the separation occurred) , command to make irregular cuts oppose to the straight plane cut.? then after the mesh has been separated pop in a reversed normal peg ?? just wondered as i use my "Select,Edit, Separate" technique every time i need to cut up large detailed meshes that require an irregular cut . .. any help would be much appreciated ;) another awesomely fine tutorial by the way .. just by watching all your tuts have made my step into the 3d printing world .. so much better cheers Angus .. keep it up and what ever you do ..... do not stop making these tuts ;) subbed ,bookmarked your tuts and had the notification bell clicked for over a year now .. :D
Just what I was looking for thanks. How do you make the male pins on one half once you’ve separated to shells? Does flipping the normals produce a flat surface and how do you make them protrude the correct amount to match the depth of the female holes? Sorry! New to Meshmixer.
I've done this multiple times a couple years ago in SketchUp when I was just getting started with modeling, it actually happened on accident but I've been using it in other programs aswell
Why doesn't Meshmixer implement its Boolean difference operation using this "inverted normals" technique, if it provides cleaner and more efficient results? Is there a semantic difference between the two operations? On a (possibly related) note, I was surprised to hear that after you put a sphere inside a bunny, they do not intersect. :-) This started my mind going to "he must be talking about the surfaces of the models, rather than the 3D bodies they represent", then to "another word for surface is mesh", then full circle back to the name "Meshmixer". ;-)
Are you using this technique in 2022? Looking at 8:26 the advantage of this technique is apparent. By delaying the addition of the cut plain until the other surfaces are all established the software can make good choices in locating vertices of the mesh of the cut plain. If the cut plain is added first as I have seen in other descriptions of methods then the software has no knowledge of where the pins will be or what size and shape they may be so it is impossible to take advantage of those surface locations when essentially arbitrarily assigning locations for the mesh vertices in the cut plain.
I was trying to do this to a mesh I needed cutting in 2, I had already done one split without pins, it's not going to be easy to get it lines up so I may have to reprint it another 11 hour print lol. Just used your technique closely following what you did. I was totally unaware mesh mixer could do this as all the join functions aren't in the edit menu... Go figure! Thanks I will have to use some time and learn mesh mixer. Am a 3D Studio Max user, and it's not ideal for 3D printing :-)
Flunked math, has 500k subscribers. At least you're good looking huh? LOL Kidding! You rock man! You're my go-to on all things 3d printing! Keep it up.
Dude! I have been pulling my hair out with meshmixer for the past week trying to get the Boolean difference to make me peg holes in a model ..... and in an hour after watching this I am away and printing (yes I know I am slow with meshmixer lol)
I do this all the time in Blender. The caveat is how I do it is messy. Regardless, pinning inside an object with Blender and then dividing it is easy. Neat tip for Meshmixer though, seems identical to the hole+group process of tinkercad.
Plane cut ops in Blender are as easy as duplicating your mesh and spawning a giant cube to use one face of the cube and the volume of the rest of the cube to cut off the pieces you want cut from the half. It's a boolean operation, unfortunately. The other boolean option is to make a tiny tiny manifold plane (
+Angus - what if you scale a copy of the bunny, say 75%, do your invert mesh trick on the copy, bring that inverted model to the same centroid as the original (of course you could do that before you invert the mesh), then combine them? (I don't have MM up and running yet). I am thinking you should be able to get a "skin" of a few mm thick everywhere and have a chocolate bunny versus having a one balled bunny. Bonus - no "maths" ;-)
You'll need to offset the mesh instead of scaling around the centroid, but yes you can do that to get a hollow :) To be honest meshmixer does have quite nice 'hollow' function already, but it can be quite CPU intensive.
Hi Angus, If you don't mind could yoiu please tell me how can I align two objects (2 different cilinders) so they could be on the same axis? One is a bit angled and I can't get it in the perfect position...
Awesome video, thanks as always. I can see someone using a method like this for an sla shapeways model. I have a question kind of about the BACKWARDS of this... I have a model that someone smoothed out and did a lot of amazing work to make a great shapeways printable model, but as such it is hollow with a hole in the bottom.... I want to 3d print this, and it is manifold and such so I COULD, but the middle would be missing infill and be a general pain to print (internal support material I suppose). I would like to REMOVE the internal shell and turn it back into a solid model for easier slicing and fdm printing. Any suggestions on this? I am looking to delete all the internal faces and then patch the hole in the 'belly of the beast', but I am having a crazy hard time selecting INTERNAL faces accurately and in large quantities in order to do this. I am a newbie with meshmixer, is there a way to slice it for VIEWING and selection without actually slicing the model? Is there another better software for this?
Awesome video mate thanks!! is there a way to know if an item snaps truly to the Bed in mesh mixer? like plan cutting an stl in half and rotating it for printing flat on the bed! I'm having trouble identifying it!! cheers
Quick question :) when you did plane cut on ball with pins in then seperated shells my issues is the whole model shells seperate as well ie i have a figure i made combine and solid all figure parts then i have a seperate box i stand him on i join the box to the figure add the pins and combine then i plane cut later on and click seperate shells and its this part i am struggling with as man then becomes many parts any help appreciated
Sadly I cannot get this to work, I'm not sure if its newer meshmixers fault or what. When flipping normals they turn out pink (shouldn't be a huge difference just color, but it refuses to work. I was hoping it would be as easy as tinkercad, making an object a hole and then combining them, but flipping the normals and combining the two meshes leaves you with exactly that, two meshes just grouped together no actual subtraction occurring like in your video.
I just tried this with latest beta of meshmixer and it works well. I started with a cube and a cylinder, put the cylinder through the cube. Select all on cylinder, flip normals. It turns it pink, as you said. Select both parts, and combine. Visibly it shows no difference, but now you do Make solid, and voila. Hole appears where cylinder was. This is why I really enjoy these videos Angus, keep the tips coming.
I need a workhorse printer that can print reliably and consistently high quality. it also has to be open source. I have experience with 3d printers and can do tinkering and upgrades. I have a maximum of $800. I am debating if I should get the wanhao duplicator i3 or the wanhao duplicator i3 PLUS. which one have you had more success with. also, if you have any suggestions other than wanhao, I would love to hear them.
Every single 3d artist know this stuff lol Normal direction is some of the first stuff you learn. Try Blender again its a lot better than it used to be. I'ma 3ds Max guy but have dabbled with them all Maya, Houdini, 3d Coat, Z-Brush etc. Booleans in these packages are far from perfect but you don't end up with the issues you get in Meshmixer. In fact making pins is easier in all these other packages lol
Agreed. When modeling large organic shapes/structures you tend to use whatever tool you can. Sometimes not how they are meant to be used but if it works for you, why not :) 3dsMax rocks!
I'm trying to make a 25mm figure print on my Ender 3, and have been trying to create pegs and holes for the figure's feet. When I use this technique--or similar--the hole looks fine until I hit Accept. Then the hole fills with triangles and random crap. Anyone else had this happen, and what was the solution?
GREAT TECHNIQUE! I was using Meshmixer trying to create a void inside a model of Mjolnir for a 1/4" steel rod to reinforce it. Using Boolean Difference, no matter how I did it it screwed up the mesh...losing triangles, deforming and rounding edges - it was terrible! Did it this way and it's done simply and VERY cleanly. thank you very much , Angus! Brilliant!
That was bloody brilliant! Such a clean technique. I'll try it this weekend.
Upping my Patreon $$. Should have done it sooner,, but this video finally pushed me in to realizing that your videos keep expanding my toolbox of knowledge. Keep up the great work mate.
4 years on, and this video is STILL useful. It saved me from making more holes in my walls (head bashing). I spent 4 days before finding this video and technique. All I wanted to do is embed weights into the middle of an STL file and this worked perfectly. Thank you!
6 years on: still super useful. Thank you, Angus!
Very helpful. Making a cavity with Meshmixer is now very easy. Thanks so much.
Angus, that was great! I can see all kinds of possibilities with your technique.
This is brilliant, especially as you can modify an existing STL without sacrificing quality. No worries about math. Think of "normal" (short for normal vector) as the *direction* of a surface. So if the "normal" points northward, the flipped normal would point south; likewise, if the "normal" points outward, the flipped normal would point inward. A 3D printer - or rather, slicer, always thinks of "normal" as outward. That is why if you just flip a sphere, it becomes unprintable.
Now if only I can learn how to use Meshmixer - if only I know how to drag an object to rotate it for examination! I can't even find move function in my Mac version.
Came here because boolean union was taking freaking forever. This was so fast and brilliant. Thanks!
OMFG this video came out at the absolutely perfect time; I have spent the morning contemplating how best to put an "air bubble" inside of an otherwise solid, high-poly model for a "bathtub toy" for my niece...and banging my head against a wall as, just like you mentioned, slapping a hole into it in Tinkercad demolished the model. So...yeah. Yaaaaaaay! :D
Thank you Angus!! I've been banging my head against the wall for hours on this, and you have such a simple solution. No more messing around with remeshing to get a boolean difference, just to have it come out all jaggy.
What a great way to make moulds. You could print them in TPE and cast resin right into them. I'd love to see an episode on that.
if you ran the pins right through you could use carbon fiber rods to reinforce the plastic
This is brilliant ! But I took it a step further. Hope you can follow. I was looking for a way to cut grooves or sculpt a surface but only to a precise depth. I could not find any app other than maybe Zbrush where I could easily do this. Lets imagine a hollow sphere 1/4 inch thick. It is created from 3 spheres. Where one is the outer surface and the other two are the inner, but both inners are a duplicate and set at 1/4 inch smaller than the outer. Then flip normals on one of the inner spheres. Hide the other inner one for now. Then use sculpting tools to pull the flipped surface through the outer surface. The length of pull doesn't matter as long as it breaks the outer surface. Then when all is done, combine all 3 spheres and most importantly then use make solid on the combination. The result is a surface with cut outs but not right through, and to your target depth. I hope that makes sense and its worth the effort as one can sculpt (albeit in a negative manner) without worrying about the depth of cut.
Perfect timing.. perfect technique.. this is exactly what I need for a specific project right now! thanks Angus! and the ARROW KEYS.. genius!!!
Years have gone by, but its exactly what I needed to know to quote on a job. Thank you, really opens up possibilities
This is excellent. I haven't been using Meshmixer for this task because of the inevitable surface deformaties. Not having to verify pin placement is going to be very useful as well. Thanks for this tip.
The cavities is what I've been struggling for a long time to make hollow planets, thanks! :D
You are my savior I've been looking for a way to do this for a while now with various softwares never could figure out a good solution so thank you.
Elegant solution. Thanks!
Wow, this is great content. Flipped normals through a different lens, loved it!
Awesome video. I wish I would have done something like this with my shield. Definitely will use this technique in the future.
man that is crazy and may come in REALLY handy for an upcoming project. Using pins to hold items is a great idea for various items in day to day stuff! I remember some lathes at the school i was at had cracked castings so we welded our own up and used the pins to hold the parts together for welding. Worked quite nicely!
Pins are awesome lol, was the casing cast iron??? That stuff is fun to weld.
+Maker's Muse the cracked ones were rubbish cast iron... other problem was people kept jamming the carriage against the headstock with the power feed which put tremendous force on the casting and unsurprisingly it cracked. the replacements were welded steel.
Pure genius.
This looks awsome. I've been struggling with this for a long time. This might just be the answer I was looking for!
Really interesting! Thank you.
Very useful if you're primarily working with meshes. Of course if you design mostly in CAD it is better to think about your joints before you export to mesh so that you end up with clean meshes and accurate mating parts (and you are not limited to pins or other simple geometries). Don't forget to allow a tolerance for the cavities if working with fixed size pins - e.g. 4mm dowel would need ~4.2-4.3mm holes.
Angus got some of the best Meshmixer tutorials on youtube! anybody know other channels that make good Meshmixer vids?
This is awesome Angus!! I have been using tinkercad to make these holes but they never came out like it should. This process is WAY better.
Thank you man! I did't know what flip the normal meant. Now it is clear!!!!
thats epic I always knew there was a point to flipping normals but didn't know what it was thanks mate
+Angus very cool, wish I known this sooner, I've been splitting a 3d printer frame into pieces to fit my build plate. great video.thanks
Thanks!
Hi Angus ..does this technique only work with the plane cut tool or would you be able to use the "Select,Edit, Separate (then fill the holes where the separation occurred) , command to make irregular cuts oppose to the straight plane cut.?
then after the mesh has been separated pop in a reversed normal peg ??
just wondered as i use my "Select,Edit, Separate" technique every time i need to cut up large detailed meshes that require an irregular cut .
.. any help would be much appreciated ;)
another awesomely fine tutorial by the way .. just by watching all your tuts have made my step into the 3d printing world .. so much better cheers Angus .. keep it up and what ever you do ..... do not stop making these tuts ;)
subbed ,bookmarked your tuts and had the notification bell clicked for over a year now .. :D
great idea! I wonder what would happen if your inverted normal was not entirely inside the object?
2:54 I knew they laid eggs this whole time
Just what I was looking for thanks. How do you make the male pins on one half once you’ve separated to shells? Does flipping the normals produce a flat surface and how do you make them protrude the correct amount to match the depth of the female holes? Sorry! New to Meshmixer.
This looks like a great tip. Thanks!
I've done this multiple times a couple years ago in SketchUp when I was just getting started with modeling, it actually happened on accident but I've been using it in other programs aswell
Interesting Concept
Why doesn't Meshmixer implement its Boolean difference operation using this "inverted normals" technique, if it provides cleaner and more efficient results? Is there a semantic difference between the two operations?
On a (possibly related) note, I was surprised to hear that after you put a sphere inside a bunny, they do not intersect. :-) This started my mind going to "he must be talking about the surfaces of the models, rather than the 3D bodies they represent", then to "another word for surface is mesh", then full circle back to the name "Meshmixer". ;-)
Are you using this technique in 2022?
Looking at 8:26 the advantage of this technique is apparent. By delaying the addition of the cut plain until the other surfaces are all established the software can make good choices in locating vertices of the mesh of the cut plain. If the cut plain is added first as I have seen in other descriptions of methods then the software has no knowledge of where the pins will be or what size and shape they may be so it is impossible to take advantage of those surface locations when essentially arbitrarily assigning locations for the mesh vertices in the cut plain.
This is how you should have made the Easter egg earlier this year, adding candy as it printed.
I was trying to do this to a mesh I needed cutting in 2, I had already done one split without pins, it's not going to be easy to get it lines up so I may have to reprint it another 11 hour print lol. Just used your technique closely following what you did. I was totally unaware mesh mixer could do this as all the join functions aren't in the edit menu... Go figure! Thanks I will have to use some time and learn mesh mixer. Am a 3D Studio Max user, and it's not ideal for 3D printing :-)
Can this be done inside blender with no lose
great work.
Neat tip man. thanks
Flunked math, has 500k subscribers. At least you're good looking huh? LOL Kidding! You rock man! You're my go-to on all things 3d printing! Keep it up.
Dude! I have been pulling my hair out with meshmixer for the past week trying to get the Boolean difference to make me peg holes in a model ..... and in an hour after watching this I am away and printing (yes I know I am slow with meshmixer lol)
I do this all the time in Blender. The caveat is how I do it is messy. Regardless, pinning inside an object with Blender and then dividing it is easy. Neat tip for Meshmixer though, seems identical to the hole+group process of tinkercad.
If you do the same plane cut operation in blender, does it do a clean job? I might need to revisit it...
Plane cut ops in Blender are as easy as duplicating your mesh and spawning a giant cube to use one face of the cube and the volume of the rest of the cube to cut off the pieces you want cut from the half. It's a boolean operation, unfortunately.
The other boolean option is to make a tiny tiny manifold plane (
Would like to add: You can separate manifold parts of a mesh in Blender by hitting P and using "By Loose Parts" from the context menu in Edit Mode.
I just use boolean in blender to cut everything and for making pins too, easy and fast.
+Angus - what if you scale a copy of the bunny, say 75%, do your invert mesh trick on the copy, bring that inverted model to the same centroid as the original (of course you could do that before you invert the mesh), then combine them? (I don't have MM up and running yet). I am thinking you should be able to get a "skin" of a few mm thick everywhere and have a chocolate bunny versus having a one balled bunny. Bonus - no "maths" ;-)
You'll need to offset the mesh instead of scaling around the centroid, but yes you can do that to get a hollow :) To be honest meshmixer does have quite nice 'hollow' function already, but it can be quite CPU intensive.
+Maker's Muse Hi angus want to come check out my live stream for like 10 min it should be in my sub box
Lightwave 3D is another great 3d program for creating and modifying objects to print.
Hi Angus, If you don't mind could yoiu please tell me how can I align two objects (2 different cilinders) so they could be on the same axis? One is a bit angled and I can't get it in the perfect position...
Thanks
Awesome video, thanks as always. I can see someone using a method like this for an sla shapeways model.
I have a question kind of about the BACKWARDS of this... I have a model that someone smoothed out and did a lot of amazing work to make a great shapeways printable model, but as such it is hollow with a hole in the bottom.... I want to 3d print this, and it is manifold and such so I COULD, but the middle would be missing infill and be a general pain to print (internal support material I suppose).
I would like to REMOVE the internal shell and turn it back into a solid model for easier slicing and fdm printing.
Any suggestions on this? I am looking to delete all the internal faces and then patch the hole in the 'belly of the beast', but I am having a crazy hard time selecting INTERNAL faces accurately and in large quantities in order to do this. I am a newbie with meshmixer, is there a way to slice it for VIEWING and selection without actually slicing the model?
Is there another better software for this?
Awesome video mate thanks!! is there a way to know if an item snaps truly to the Bed in mesh mixer? like plan cutting an stl in half and rotating it for printing flat on the bed! I'm having trouble identifying it!! cheers
Could this method be used to create voids for sending wires through 3D printed objects for things like LED effects?
Quick question :) when you did plane cut on ball with pins in then seperated shells my issues is the whole model shells seperate as well ie i have a figure i made combine and solid all figure parts then i have a seperate box i stand him on i join the box to the figure add the pins and combine then i plane cut later on and click seperate shells and its this part i am struggling with as man then becomes many parts any help appreciated
Sadly I cannot get this to work, I'm not sure if its newer meshmixers fault or what. When flipping normals they turn out pink (shouldn't be a huge difference just color, but it refuses to work. I was hoping it would be as easy as tinkercad, making an object a hole and then combining them, but flipping the normals and combining the two meshes leaves you with exactly that, two meshes just grouped together no actual subtraction occurring like in your video.
I just tried this with latest beta of meshmixer and it works well. I started with a cube and a cylinder, put the cylinder through the cube. Select all on cylinder, flip normals. It turns it pink, as you said. Select both parts, and combine. Visibly it shows no difference, but now you do Make solid, and voila. Hole appears where cylinder was.
This is why I really enjoy these videos Angus, keep the tips coming.
Try combining the pins (with the normals flipped) with the main part BEFORE you do the slice. That worked for me.
are qidi printers good I'm thinking about buying one but not that much info out there
I need a workhorse printer that can print reliably and consistently high quality. it also has to be open source. I have experience with 3d printers and can do tinkering and upgrades. I have a maximum of $800. I am debating if I should get the wanhao duplicator i3 or the wanhao duplicator i3 PLUS. which one have you had more success with. also, if you have any suggestions other than wanhao, I would love to hear them.
Every single 3d artist know this stuff lol Normal direction is some of the first stuff you learn. Try Blender again its a lot better than it used to be. I'ma 3ds Max guy but have dabbled with them all Maya, Houdini, 3d Coat, Z-Brush etc. Booleans in these packages are far from perfect but you don't end up with the issues you get in Meshmixer. In fact making pins is easier in all these other packages lol
Agreed. When modeling large organic shapes/structures you tend to use whatever tool you can. Sometimes not how they are meant to be used but if it works for you, why not :)
3dsMax rocks!
Welcome to the real world... we have no idea what we're talking about...... but somebody needs to do it... TD
Hey Angus, what are a few programs you use to make your meshes.
I model in Onshape personally, but a lot of meshes I convert from games or 3D Scans are .obj which is why I use meshmixer a lot.
Ok thank you, are you able to make complex models on onshape?
Define complex, it's perfect for complex engineering assemblies but not what you want to use for organic designs, like character design!
I've got a fair few vids on Onshape if you're interested in seeing what it's like :)
Yes, I would be very interested in seeing them.
iv touched that death claw ;) i just use f360 to cut holes out :P
Hmm now I kinda wanna print a sphere like that in clear pla, add a led and I bet you have smth awesome!
Plot twist: we can now 3D print black holes....
Thanks, but works much more easier in 3D Builder
yeah kid that's real great when you are plane cutting what about when you can't easily do that after the fact???
Mesh mixer is a pile of crap for destroying surfaces and crashing.
I'm trying to make a 25mm figure print on my Ender 3, and have been trying to create pegs and holes for the figure's feet. When I use this technique--or similar--the hole looks fine until I hit Accept. Then the hole fills with triangles and random crap.
Anyone else had this happen, and what was the solution?