Rethink how you use 3D printer infill! 

Will watch this later, literally just popped in to say that's an S-tier thumbnail.

One of the patterns you thought was just in there, I actually have a specific but incredible use for. On the concentric pattern, I actually have two uses. One is purely aesthetic, on transparent filaments sometimes you don't want the infill to show and strength isn't paramount. The second use is more functional. On TPU prints, flexibility is always needed, but it can vary in how much flex is desired in one axis. I find the concentric infill makes for a very strong vertical strength but very weak lateral resistance. This is super useful if I don't want to spend hours in CAD to do the same.

Was about to start my most ambitious 10 hour print with gyroidal infill. Chose gyroidal on the basis that it looked cool. Decided to watch your video before I began. Changed to Cubic based on your results and saved 3 hours on my print time. Thank you sir for the tip. This was S-Tier RU-vid content.

I appreciate the hours/days spend doing this massive comparative evaluation

Cubic was my first love...

I like how the video doesn't waste time with lengthy testing recordings and just talks about the results. Also, I like cubic too though I go for grid when strength doesn't matter much as it's faster.

Concentric, Hilbert curve, archimedian chords and octagram spiral are great for top/bottom infill. They usually create a better looking surface finish than the standard linear infill. Octagram spiral with a silk filament on a smooth sheet give amazing results. Hilbert curve on top infill makes for a surface comparable to a bottom layer on a textured sheet - helps to make both sides look similar in PETG.

The amount of data and research you have done on this is amazing and very valuable for many of us who 3DP. Thank you for creating this video and helping to teach us all more about infill and strength of printed parts.

So glad you did this in PETG. i make a line of products for the hair industry and primarily use PETG.This video has changed how I will be utilizing infill differently now. Thanks again.

A silly problem with cubic is that you can often see the infill pattern slightly through the outside in daylight and it makes the parts look cheap where with gyroid the inside looks fuzzed out.

One advantage that Gyroid has is that it allows the print to be filled internally to add weight or possibly with foam for strength. I've printed some tall sculptures that I've added sand in the base to make them less "tippy". The closed patterns won't allow the sand to flow beyond their individual chambers. I also like Gyroid for it's multi-directional support.

Another vouch for the concentric, hilbert, archemides, and octogram is that as they're completely free of any isolated pockets and can be taken advantage of when you want to fill in the void fraction of a 3d print to further strengthen them. Such as as filling them in with resin. You can't do that with a lot of the other infill options.

Also what about cross hatch, was it too late to include it? Looks very promising, aligned rectilinear meets gyroid 😅

Concentric and archimedian chords have some use for flexible materials when you want a more flexible infill. It still provides support for top layers, but it doesn't make the part as rigid as something like cubic would.

Great tests and a perfect way to present the results. Also, I have say that your ad integrations are very smooth without being annoying - love that!

This aligns pretty well with my theories and experience. I generally used cubic wherever I wanted maximum strength and a faster to print infill where I just needed support. I also tend to rely on more shell thickness any time I want a part to be robust. Thanks for all the testing!

Such a shame you didn't test Bambus new "Cross hatch" infill pattern as well

I wish a slicer would implement a feature to be able to draw internal walls in parts. You can trick the software to do it, but it doesnt always work great. You could tie features together with thick walls, and use a low infill everywhere else.

It's not often you can finish watching a video and immediately start using that information. Literally my very first print after watching this video was where I got to use this knowledge. With a complete enough understanding of the subject I can quickly make good choices. How I look at that dropdown has completely changed. Before this video I would "play around" with various settings. I can still play around. But now I know what to look for. I know what to choose, what to watch out for, and what to expect. This is really good stuff. Oh, and nice shirt!

I use the cubic pattern as it's the strongest from my experience. I had printed an extender to connect 2 monitor posts 6 inch in length. While this worked initially... after about 3 months the print snapped dropping the monitor. I had used 100% infill. When I used the cubic at 50%... it did not snap it just eventually started to lean and then show failure at the same stress point as the solid peice... thanks for your tests, helps confirm what I already know

The thumbnail is just the best. Very informative.

Damn, I was hoping for cross-hatch and the updated 3D honeycomb to see how it performs

What’s with cross hatch? Orca Slicer.

This was impressively comprehensive. Thanks for your work!

That Prusa XL looks so cool. A lot of asthetically pleasing touches to this video. Thanks for not printing the tests in yellow and red.

Awesome to see that the pattern I've emprically has gravitated towards, aligned rectiliniar, gives the "best" top surface look. Even though I only ended up using that, since it was the combination of fastest and non-crossing that I've tried. I only print for "looks" as in terrain for wargames and such.

I’ve been playing around with infills and shell thickness, trying to figure out what cases need which one. Thank you for saving many late nights! As always great video.

Thorough and "to the point" analysis, as always. Thank you for educating me!

Hilbert curve on a powder coat textured bed gives a flawless first layer with ABS, ASA and some others. Straight lines on parts that catch light will show through in many circumstances. Hilbert is my go-to first layer for anything that has to be perfect.

I appreciate the thoughtfulness and thoroughness of Tom's videos. I print a lot feet for air compressors, leveler feet for freezers, dish washers, workbenches, et al. My main concern is compressibility/axial loads and my default infill is gyroid.

Wow this must have taken so much time to produce! Congrats and thank you, I know what I’ll be going for next print!

I've seen a few others do these same tests. Different methodologies for each. I'm glad the tests continue, often showing the same results.

Gyroid! The strengh to weight ratio of infills was tested in 3D Printing Academys video around 5 months back. Its the reason i use Gyroid almost always. 3 walls all around and between 15%-20% infill for max strength to weight ration.

Great video, I like how detailed all the tests are (especially with the data). Interesting on this topic would also be, how the infill change the damping/vibration/stiffness in parts. This would be great information for many mechanics (as an example when you build a printer like a Voron). Proper test would probaly be some measurements on the eigen modulus and frequency. Or are there already some tests with proper data on that (didn't find anything like that yet).

The color grading in your videos is gorgeous.

Personally I use rectilinear for its clean prints and very minimal internal wiping, it also prints nicely on both bedslingers and core xy alike. One thing I find it particularly useful for is checking that bridging and general extrusion is in point when I’m switching filaments for different prints as if it is off even slightly you see it won’t connect at walls or sags in the infill and is really easy to see. Top layers are nice due to the even square finish if you want top keep top layers to around 4 instead of going higher and using more filament :)

I was hoping to see cross hatch versus gyroid as orca has recently made cross hatch the default in many profiles.

Thanks Thomas, for doing this tedious work more of us would have wanted to got done to get the results you showed.

For the multiple nozzle sizes in same print, try upping the extrusion multiplier by 1 or 2% on the nozzle that prints the infill. I find it helps with adhesion between perimeters/shells and the infill.

Fascinating stuff. I'm definitely going to try aligned rectilinear next time I have a purely aesthetic print with a broad, flat surface on top. It's a niche use-case, but far from an unrealistic one.

Hilbert curve is super useful in both infill and top/bottom layer patterns when a part is prone to warping. I use it to print PP or PETG-CF parts that would otherwise require an enclosure or a massive brim.

I think your thumbnail was one of the main reasons you got 50K views in one single day! -It's just perfect! 😃 -Anyway, I'd like to put a note up that I've used 1.2mm wall thickness for more than 2 years and I've gotten quite good results with both PLA and PETG. I'm using and old, old version of Cura and won't change anytime soon, so I'll not have the benefit of getting cubic infill (which I'd like to use). [I never see any infill-artifacts on the surfaces, because I use so thick walls - except from of course when I use translucent filaments]. Excellent video; I could watch from start to finish without falling asleep (most YT-videos make me fall asleep nowadays). 😃

Orca Slicers new Cross Hitch infill pattern is GOATED. You def have to give that a try. It's a cross between Gyroid and Aligned rectilinear and its amazing.

Nice to see the 3D Cubic Infill I favor being the best choice 😁

Thomas, our 3D printing explorer. He goes very far away to safe us from mistakes. Thank you Thomas for your dedication 😍😍😍

Fantastic. This is what I have been wondering for a while as I print mainly for structural rather than decorative use. I felt that more perimeters were the better option and defaulted to 7, but I also added more infill for parts I really wanted to be very strong and often hit 70% . I think a little experimentation similar to yours is called for on the infill density impact

Great video, love the work you put into things. That is a huge effort for adjusting the weight to be the same. Thanks !

The "dubious" infills are often good for translucent materials. There are some aesthetic things I make with TPU, because you can print at almost any speed without affecting clarity. When I do this, I use concentric, because the clarity is relatively even in all x/y directions. So you can adjust your walls and infill to adjust the depth.

this is a perfect educational piece and dope use of the Prusa XL.

Gyroid has been my go-to for the longest time now. Great strength to weight, reasonably quick printing, and minimal external surface artifacts. Another benefit is that if you do need to fill the print, all of the airspace is contiguous, so filler materials (resin, plaster, sand etc) flows fairly easily to fill the space.

Awesome stuff, now if only someone would test which infill pattern is best for warping 😊

The dubious patterns just look great when they print, getting factual data about their strength is quite nice 👍I mostly use the gyroid pattern though, because most of my parts do not need much strength.

Before the video I used cubic subdivision (I believed it was the more geometrically tough pattern). Now I'll still use it but with a great video to support my choice. Thanks Tom.

I'm a noob to 3d printing and I'm happy to learn that my intuitive choice of adaptive cubic with less infill and thicker shells is such methodically proven 😀

Another thorough and useful test Thomas. You are a gentlemen and a scholar my friend. I have been using the Voxel PETG + for a few months now and it has been performing great on my XMax3. I was hesitant to believe the claims it works on high speed printers but it certainly does. It sands much easier than PLA as well.

Fantastic sanity check. Thanks for your work!

Good Video... in aerospace we use thin honeycomb and skins. The load paths are, as you suggest, only in the skin which takes all bending and direct tension/compression. The infill is only for out of plane or transverse shear but also can prevent skin buckling in a compressive or bending load. Honeycomb core has no bending strength and flexes just like you demonstrated in the video.

I was really hoping to see the two different nozzle sizes! Great video

In the animation at 5:25 you can see the problem with Gyroid as it can happen that none of the surface connects with the infill if you are unlucky with your design. that leads to weak spots in terms of infill strength. I think that the crosshatch pattern gives the best compromise but it's not widely available in all slicers.

Going into this video rooting for my beloved cubic subdivision, excited to see the results! Edit: Hecc yeah, let's go cubic! Glad to see you mentioned cubic subdivision as well in the end, even if it wasn't tested. If you ever return to the subject and make another vid comparing the physical attributes of the few best infills in more detail, I'd gladly watch!

I liked this video for the thumbnail alone, very creative!

I do not own a 3d printer but I've watched a reasonable amount of 3d printing content just because one day I will own one... This info may be out dated by the time I own one but I must -MUST- watch this video because the thumbnail is just that cool.

Best thumbnail to video title I've seen so faar, it even made me giggle 😂

For thicker infill use infill line multiplier (as named in cura) so each layer is double thick. This is for strength as it add rigidity to an otherwise flexible thin wall. Half the infill and double the multiplier. Speed and material use-age are similar, but strength is better

Came just for the great thumbnail! Stayed for the great information, as always.

I never tried the cubic, but I love the gyroid. Its wavy shape saved many complex prints-it allowed the building of difficult bridges.

I'm ride or die for adaptive cubic! Use it for everything, and I mean everything, it's just my standard infill, mostly cosplay/display props but also helmet/armour which are like 2-3mm thick infill space, and even large miniatures.

I believe cubic is still the pattern that produces the most fully sealed cells / air pockets, correct? It's a pretty rare use case, but this would be important for insulating properties.

Hilbert curve should be the least warping infill, I would love to see it tested

CNC kitchen did a pretty deep dive on this issue a while back, at least in respect to shell thickness and strength. Infill has relatively little impact on part strength even when it's set pretty high. I usually run 4-6 perimeters with as low density possible with lightning infill to save on material since infill contributes relatively little even in different use cases. The only con of lightning infill is slow print times though.

A/B test for thumbnail is insane, ofc i will click on brain infill picture lmao

Exactly what I am preaching in discussions forever now: use rectiliniar/triangles as it is fast, efficient and provides decent strength. For more strength use more walls. And for non mechanical parts lightning can be a valid option to support top layers/internal structures. One topic that wasn't covered: using infill for aesthetic reasons, e.g. I've used hexagon infill without top/bottom layers as radiator grilles, roof racks, etc. for my 3d printed RCs

Great idea to scale down, also reduces waste!🙌

All that to say that you validated my intuition that shell thickness is critical to strength. I can’t think of any place where I’d use more than 10% infill. A small lever arm, for example, would be solid with enough perimeters. Infill is mostly there to support the top layers

My favorite infill for 90% of my prints is the new Cross Hatch infill! Its faster than Gyroid but has similar strength.

I like using cubic subdivision in Cura, it becomes more dense of a pattern in narrower parts and less dense when filling large gaps

Great video, Thanks for sharing your experiences with all of us. 🙂 My infill if almost adaptive cubic as a old video from CnC kitchen :-)

Never messed around much and stayed cubic - I‘m fine with that and now I know why 😁. But one thing I learned: I will not push the density over 30%. I sometimes cranked up to 50% for rigid parts.

most surprising result is the quality of aligned rectilinear, very cool. There should be some setting where you can just make the last few layers of a print before the top aligned rectilinear and then the rest cubic. Overall, excellent video!

Depending on the application of our print, appropriate strength should be considered. For example, if it is going to be compressed a lot or carry some load, will it experience shear or bending forces. Even if this research covers a few cases, it still was very insightful.

To me, Hilbert Curve is more of a top surface pattern than infill. It helps the top of an object match the textured build plate.

I occasionally use patterns from the "dubious" category, typically Octogram Spiral for either the Top or Bottom (or both) surface pattern. When I do this it is purely for cosmetic reasons, they can add a nice subtle surface appearance. Hilbert and concentric also work well for this. For infill itself, on typical prints I almost always use Gyroid or Cubic at typically 15-20% along with 3 walls, 4 if I am concerned about strength.

Thank you for your effort

0:04 Bro is NOT Zack Freedman

Another problem with the self intersection of grid, triangles, and stars is that the self intersections always happen at the same X/Y coordinates (3 lines thick for triangle!) This can lead to a noticeable bump forming that can catch on the nozzle tip much worse than cubic. It can also make a REALLY nasty rattling sound as it drags along.Found this out the hard way after building my Mk3S all those years ago and the included GCode for the Nefertiti bust failed several hours in from the buildup (and probably not perfect adhesion to the build plate). Honestly it amazes me that grid is still the default pattern in PrusaSlicer (I don't know about the other forks) after all these years. As you've shown here, and as I've seen over thousands of print hours, cubic and it's direct derivatives, perform as good as or better than grid in most situations.

The Hilbert curve is actually very useful for some specific usecases. When boring into the part in 2 locations you can be sure both holes are connected and you can suck air through them, no matter where you bore or what shape the object is

Ive been using rectilinear with combined layers (infill combination) for a long time in Bambu Slicer. Its fast, doesn't waste material and doesn't print over itself. Its fine for anything that doesn't need a lot of strength. If its just for support I can go down to 5% infill in many cases without issue.

Here is a long description of my experience probably not many people have so I want to share in case someone finds it usefull. Recently I have been printing very large molds for someone who then makes a thick fiberglass master model in them for further finishing and polishing by hand. The final serial production negative molds get then made on this polished master model. The printed molds therefore need to survive a single wet lamination process and usually get destroyed during the extraction of the very rigid master model out of them. The designer of the molds maxed out the size of my 500x500x500 Rat Rig on some of them (he designed the sectioning of the mold arond the size of my printer). Finding settings that would produce the required parameters was interesting. Requirements are smooth surface, enought stiffness and no warping. I ended up using 4 perimeters with 0.4mm nozzle and 0.2mm layer height. This gives decent surface smoothness and some wall thickness in case imperfections need to be sanded down. For most of the parts I used 4% gyroid infill. This gives enough support to even very gently curved walls to hold their shape while having the resing squeezed out of the fabric by some rollers. In areas where M6 bolts are used to join multiple sections of the mold together I used 20% infill to better resist the compressive strength of the bolt. Gyroid got picked over cubic because in my experience the more long straight lines you have in such huge print the more it wants to lift its corners off the bed (or bend the bed off the magnet) and then some sections of the mold no longer fit together. Since PETG was requested this can be a serious issue on such big prints. Not as bad as ASA would be but noticeably warps more than PLA would. Gyroid with its waves does not pull on anything as the cooling extrusions contract. And as it turns out when they need to destroy the printed mold to get the master model out then gyroid seems easier to dig out with chisels in large chunks (not sure why). One time I used lightning infill because it was by far the fastest and did not compromise the mold where it would matter. This mold was basically almost 500x500 base with something resembling a flat top mountain coming out of the base. All the functional walls wer curved in various directions relatively sharply and just the top enclosing the volume needed support to print cleanly. With 4 perimeters and lightning infill set to 20% it saved about 24 hours of printing and 1kg of filament compared to 4% gyroid. And all the curved surfaces where fiberglass was to go were still perfectly shaped and rigid enough. It is a rare case but here lightning was the best despite this beeing a technical functional print.

I have been using cubic since the beginning for the majority of my projects. Just made sense to me.

I like the idea of printing thicker infills to save time. I think delamination occurs as separately printed structures have time to cool and therefore don't adhere to one another. I have recently printed small-ish parts that needed some strength and wall-to-infill ratio made very little difference. I found the biggest gains in strength by lowering printing speeds altogether.

good video but as on all videos in this topic im still missing one crucial test.... 100% infill vs "infinite" walls (and yes (at least in cura) it makes a difference in printing and strength...)

I can see, from your data, there would be good use made of taylored infill such that it rapidly went to zero, away from the walls (shell). Just like nature designed bones' trabeculae. Worth looking up for some ideas. It supports what you said about large area, thin parts too. Great video, thanks!

You took a different approach to this than other youtubers, which I liked, in adjusting the infill to get the same amount of material in the part. Some of the same mistakes, in my opinion, focusing on the top line modulus of rupture. For most of my prints, I care more about the rigidity of the object under normal loads rather than the ultimate strength. More testing of different elastic moduli is needed, as well as testing of different orientations, since additive manufacturing is fundamentally non-isotropic (outside of maybe laser sintering).

mostly used default grid pattern since it prints fast and is good no matter the orientation, shape or size of your part. over 30%/35% infill was never bringing me any additional benefit and sometimes even decreased strength and quality. below 10% infill (about a 1cm bridge distance) part strength as well as top support is about the limit. A good default is 10% (1 or 2 shells) for fast prints 15% (2 shells) for everything or 20%/25% (2 or even 3 shells) for strong. honey comb is kind of good for strength but very slow for big models even on old printers. most patterns are a wast of time and material or highly situational at best. 3d rotated patterns tend to have bad layer adhesion in some cases which may even harm strength.

Infills like Hilbelt curve and Archimedian chords work well with TPU when you want to have a more pillowy feel on the part.

You got me with the thumbnail xD that was really funny

I use a variation of infill patterns especially for flexible materials to get the right properties

I think these results are similar to those of CNC Kitchen years ago. Always nice to see two different tests show similar results.

The patterns octagram spiral, concentric, and hilbert are best for top and bottom solid infills, NOT volume infill. Octagram spiral creates a nice starburst effect, and concentric makes radial light reflections, especially with metallic silk PLA. Hilbert is kind of strange but it's useful for preventing warping. For infilling volume, my go-to is always adaptive cubic or gyroid. Aligned rectilinear is most useful for printing clear "glass" from transparent filament because it eliminates trapped bubbles when printing at low speed.

Nice review. My infill is "default" because I never give it much thought. If I need a stronger part, increase the shell and infil percentage. Otherwise, I don't mess with the pattern.