Redesigning Models for FDM Printing

FDM (Fused Deposition Modeling) 3d printing is a marvel, and it has revolutionised the way that I make the toys I push around the wargames table while making "Brrrrm brrrm BOOM!" noises. However, it is not without its limitations.

1:100 scale (15mm) Toldi II Hungarian WWII light tank
The major structural limitation lies in the fact that the strings of molten plastic can't be laid down in mid-air, and need some sort of support to lie on. The printer can make its own supports as it goes along, and usually they do a pretty good job at supporting, but the bottom surfaces, lying on those supports, can be pretty ugly. Often enough, that doesn't matter too much for my purposes, because those surfaces will seldom be seen.

Shown here to the right is a 1:100 scale Toldi II which has been printed sitting on its tracks on the bed of the printer. The bottom of the hull, and beneath the turret where it was raised up above the print bed by the turret-plug, show the characteristically loose fibrous-looking surface you get over supports. It's ugly, but you never see it, so it doesn't really matter. You can see that the bottom of the tracks, and the bottom of the turret plug, both of which were built up directly on the print bed, are much smoother.

Although the bottom surfaces aren't usually visually important on these vehicle models, there is a situation where the imprecision of a supported surface can matter. That is at the meeting between the turret and hull.

These two models (left) of the Vickers Light Mk.VIb were modeled differently. The one on the left had its turret printed in one piece, the same way as the Toldi II above, and you can see that the loose net-like structures left behind by the supports have somewhat rounded off the bottom edge of the turret, and they lift it away from the hull. The model on the right had its turret printed in two pieces, as shown below, so that the bottom edge of the turret itself was built up directly on the printer's glass bed, giving a very smooth surface and a clean, sharp edge. It sits right down in contact with the hull top.

The way I did this was to split up the turret into pieces. This picture (right) shows the whole model, laid out ready for printing.

When I was cutting the turrets up, at the same time I punched a hole through the turret plug, with a matching one in the bottom of the turret itself. The small cylinders you see here are used as locating pins, to ensure that the pieces get glued together accurately.

I also use the hole in the turret plug to house a 3x3mm cylindrical magnet, with a matching hole and magnet in the hull. The magnets are there to allow the turret to rotate freely without falling out and bouncing away under some furniture where it would never be found again.

You will observe that the hull is printed standing up on its tail. The reason for this is because this orientation is optimal for reducing visible layer lines on the vehicle's sloping panels, and it also gives me better, cleaner detail in the track run.

This turret for a British A10 cruiser tank (left) has been treated in the same way, except that the turret ring has also been detached from the turret and is printed along with the turret plug.

This arrangement maximises the cleanliness of the edges where it matters, where it will be seen, while keeping the number of individual parts to a reasonable minimum.

I could, if I so chose, split up the models into a multitude of component parts, each so arranged as to print to its best advantage. However, part of the appeal of a 3d printed model, for my purposes at any rate, is simplicity and speed of assembly. If I want to build a whole kitset model, I'll buy one. My aim is to find a happy medium between model quality and convenience, and this system achieves that for me.

All of the base models I've used as examples in this post have been by m_bergman (Toldi II, Vickers Mk.VIb) and TigerAce1945 (A10). Their models are available on Thingiverse, and I highly recommend them both.

A10 Cruisers (15mm, 3d print)

This is a pair of 3d printed 1:100 scale British WWII A10 Cruisers, along with some 15mm Battlefront BEF figures in my sabot bases. The model is by m_bergman (or possibly TigerAce1945, I'm not 100% sure), very slightly modified by me.

There are some definite issues with these prints: the side shields didn't print, I suspect because they were too thin, and I got a bit of warping on the turret base, a problem I haven't had to deal with for months. Also, on one of them there is a slight layer shift with associated under-extrusion, and what might have caused that I don't yet know. However, neither of them is so poor that it needs to be binned, and they'll do fine on the wargames table.

I am going to have to do a bit of tinkering with my printer though, to get it back to printing properly again.

Blender 2.80

Blender 2.80 is now officially in beta.

From various bits and pieces I've seen about it on Youtube, it looks as though many of the UI and UX changes will be pretty good in the long run, but they're so extensive that I'm now pretty much completely lost in it.

I no longer seem to be able to set specific values for things like extrusions, bevels, and so forth nearly as easily, as they're no longer immediately accessible on the toolbar. And when I've tried to do so via the pop-up gizmo, the measurement values appear to default to metres, in spite of the fact that I've set them to millimetres in the global settings. These are just a couple of the UI issues I've encountered in just a short time of playing with 2.80.

I'll be keeping an eye on it, and I'll have to learn my way around the new UI eventually, but for the moment the changes are such that they've made my modeling life harder and less precise, rather than the other way around. I'll be sticking with 2.79 for quite a while yet, I think.

CMP Chevy 15cwt 3d print

Here's my 3d printed CMP Chevrolet 15cwt light truck, all painted and crewed. The gunner is an assemblage of various bits and pieces out of the spares box; I think (though I'm not sure) that the figure is a gunner from a 25 pounder. It's from Battlefront, in any case, as is the Bren gun.

I have a bunch more of them awaiting paint, but this is the only one I've printed with the roof hatch open. Which turns out to be a relief, since putting the gunner together was kind of a pain with my decrepit eyes and fingers.

The markings are entirely specious; I know almost nothing about British WWII softskin markings, so I just made them up.

Sabots for the Desert

I painted these Battlefront 15mm 8th Army figures many years ago for Flames of War when it was still in its first edition, and they're pretty crappy. They really need to be repainted, pretty much from scratch. I want to be able to use them for Battlegroup Tobruk and Torch, so I've taken them off their old multi-figure FoW bases, and put them on to ½" (12.5mm) steel washers.

However, moving a bajillion individual 15mm figures is a bit of a trial, especially when their exact formation isn't immediately relevant to the game. So, to combine the flexibility of individually based figures with the convenience of multiple bases, I've designed and printed some magnetic sabot bases in 5, 4 and 3 man groups. Those numbers will give me all the combinations I need with no more than two bases per unit. I use 3mm x 1mm rare earth magnets in them, cheap as chips from China.

If it becomes necessary, the figures can be dismounted from their bases in the blink of an eye, or remounted again almost as quickly.

Ridiculous Land Dreadnaught

I designed this ridiculous dieselpunk Land Dreadnaught for 6mm a couple of years ago, and I thought I'd rescale it and bring up the detail for 15mm–20mm. At this scale, it's about 195mm long. I guess it could be used for 28mm games at a pinch, though in that scale it's not really any bigger than most tanks.

The figure is the 15mm SidScale from Printable Scenery, included to give an idea of the size of the beast.

I haven't yet figured out how I'm going to split it up for printing. The turrets will all be detached of course, and sockets punched into the hull for them to rotate in, but the big turret needs a bit more work I think. I want to make the main gun moveable, and I think it needs a bit more clutter up on the roof.

Later:

Some guys on the Tabletop 3d Printing FB group suggested that it needed wider tracks, and after initially reeling in horror at the thought of rebuilding them, I realised that widening them wouldn't actually be all that difficult.

So I did.

I also added a 20mm SidScale figure for size reference.

Later:

I added a massive access hatch with lifting lugs to the top of the main turret, for getting that big gun in and out I guess.

I also slapped on some panel lines, and some more rivets, because you can never have too many rivets.

I also added a machine-gun sub-turret to the top. It's the same basic geometry as the other gun sub-turrets, so one could mix and match cannon and machine-gun turrets just by printing the number of each one wants.

Next I need to figure out how I'm going to mount the gun so that it can be elevated or depressed, and then how to split everything up for printing. It's possible the best option might just be to only make the turrets and main gun separate objects, and to print the hull and side-sponsons all as one piece. We shall see.

CMP 15cwt (15mm)

I remodeled my CMP Chevy 3-tonner into a 15cwt light truck.

I thought it would be a simple job — just shorten the bed and rear chassis, move some things around, cut the canopy in half and resculpt it a bit....

It was not as simple a job as I had expected.

Partly due to lack of forethought in the original modeling, with respect to making changes in the future, but mostly because I decided to have a go at open flaps at the rear of the canopy, and (probably due to my inexperience with sculpting in Blender) that proved to be a much tricker task than I thought it would be. Somehow the smooth, clean sculpting the Youtube Dudes manage as a matter of course eluded me.

Still, it's done now, and the first test print is on the printer as I type this. Hopefully I can start to replace some of the Austin Tilleys I've been using for all my light trucking needs up until now.


Here's the test print, finished. I've removed its supports and airbrushed it with a coat of primer. The officer is a WW1 british figure from Peter Pig, the guy sticking out of the roof hatch is (I think) a gunner from a Battlefront 25 pounder.

Overall I'm fairly happy with how it turned out, and I've learned a bit about how not to make my life more difficult than it really needs to be.

CMP Chevy — FDM Test Prints

Left: 0.08mm layer height
Right: 0.1mm layer height
I've done a couple of test prints of the CMP Chevy model I designed the other day. Both models have had their supports removed, and been airbrushed with a primer coat, but no other post-processing has been done as yet.

On the left, the most recent version, after I'd sculpted in the folds and billows of the canvas tilt, and printed at a layer height of 0.08mm, that being an even multiple of the Ender 3's Z-stepping.

On the right, an older iteration, while the tilt was still in its basic geometry, printed at 0.1mm.

There is not a great deal of difference between the two in terms of layer artifacts, but the layer-stepping in the 0.1mm model is definitely more visibly pronounced on the sloping upper surfaces. Going to the finer layers does add to the printing time — another 25% — but it will be a bit easier to smooth down the upper surfaces.

As far as the sculpting of the canvas tilt goes, I'm fairly happy with it. The modelling on the sides could maybe be exaggerated a little bit more, but it doesn't need too much. Go too far, and it will start looking overly cartoonish. I've learned that I didn't really need to worry about pre-modelling the folds of the canvas over the ends before moving to sculpting in Blender; in fact, it probably made my life harder than it needed to be. I could have just modelled up the folds entirely within the sculpting mode.

Softskins

Trucks are not something that most wargames model companies tend to spend much effort on. They'll do some of the most common ones, just to show willing, and leave it at that. I can't say that I blame them, since most wargamers are equally uninterested in spending money on anything that doesn't have armour and goes boom.

I've been looking through my old Military Modelling magazines for scale drawings of some of the more interesting looking British trucks of the interwar period and WWII. I don't really need them, as such; I have enough common-or-garden 15mm truck models to stand in when I want to deploy them on to the game table, but I'd like to be able to field some of the funkier looking vehicles that were pressed into service. The interwar Thornycrofts, for example, that were still being used in WWII, and looked like something out of the Great War.

This one is the first fruit of my digital trucking loins, a CMP Chevrolet 3-tonner. It's not a truck that is hard to come by a model of, even in 1:100 scale, but I did it to learn my way around modelling non-tankish things, and also because this one will be dead easy to change to the 15cwt version just by cutting the back in half and moving a few bits around. The main thing I need experience with is the fabric tilt — I need to learn just how far I need to take the sculpting to ensure that it looks appropriately canvas-like when it's printed on my FDM printer.

Sabot Bases for 15mm Infantry

 I like to base my 15mm figures individually for flexibility, but it's usually much more convenient to move them when they're mounted on multiple-figure bases.

The solution to this issue is, of course, sabot bases, and I've tried several methods of making them. Up until now, the most successful has been laser-cut MDF, with thin card or fridge magnet material glued underneath.

However, now that I have a 3d printer, I reasoned that I could create magnetised sabot bases with a minimum of trouble, just ten or fifteen minutes design time in Blender, and about twenty minutes to print this particular three-man base. Printing a whole army's worth of bases will take a while, but I can put them on to print at night and take them off the next morning. Easy-peasy.


I use 3x1mm rare-earth magnets I bought from China. I have hundreds of them, and they cost very little — I don't recall exactly how much, but it was something like $2.50 for a hundred.

The magnets are thin enough that the sabots don't have to be overly thick, and strong enough that I can pick up the whole base by one figure quite securely.
I use two magnets per socket, because I base my 15mm figures on steel washers, which have an inconvenient hole right in the middle where it would be most convenient to put a magnet. However, the magnets are cheap enough that doubling up isn't a big deal, and it does make for a more secure hold, with one magnet on each side of the base.

I'll judge this experiment a success, and go ahead and make sabots in sizes to suit my army organizations. For the British, that means one five-man and one 3-man base per section, which allows me to split off the Bren team if need be. The most tedious part of making them all will be painting and flocking them to match the figure bases.

Tiger (P)

Ferdinand Porsche's submission for the chassis of the tank which later came to be known as the Tiger was not successful in that respect, but the chassis was used for the Ferdinand 88mm heavy tank destroyer. Just one saw service in the gun-tank configuration, and it was used as the command vehicle for a company of Ferdinands in Russia. It was lost in 1944.

This 1:100 scale model is 3d printed, and I've photographed it with a Zvezda Ferdinand in the background. I don't know exactly what markings the original had, so I've just given it some generic command-ish markings.

Update:

I'm informed that the tank was this one, Panzerbefehlswagen VI(P), turret number 003, commanded by Hauptmann Grillenberg, Eastern Front, Early/Mid 1944.

So I might have to re-paint the turret numbers. Dang.

Lizard, finished

Here's the Guy Lizard ACV I showed in the raw in my last post, now all painted up and ready for service.

It will cost me an extra 12 points to upgrade my BEF FHQ from a staff car to this, but it might be worth it to keep them safe from my wildly erratic mortarmen.

Lizard Guy. I mean, Guy Lizard.

I've put together a digital model of a Guy Lizard ACV in 1:100 scale — estimated from photographs with blokes in them, since I have no concrete dimensions at hand — and I've got it on the printer at this very moment.

Hopefully next time my BEF commander gets bombarded by his own mortar battery, he'll be safe and snug inside an armoured shell. (I can't remember, offhand, what it costs to upgrade from a staff car to the Lizard, but what the hell...)

Because the roof and engine cover have such gently sloping surfaces, I split the model in half to print it vertically rather than sitting on its wheels. This minimises the visible print lines, which can be distressingly obvious when the slope is very gradual, even at very fine layer heights. I'm kind of curious to see how it will turn out, but I'll just have to wait until tomorrow morning to see.


I've put the model up on Shapeways at http://shpws.me/QQLF — whether it will pass their pre-printing checks is anybody's guess, as they're steadily becoming a more and more crappy business, and their site has become next to impossible to use.


Here's my two-part FDM print, fresh off the printer and assembled. I've photographed it alongside an undercoated Dorchester as a scale reference; I suspect the Lizard might be just a tad too large, as the Dorchester was noted for its spaciousness. However, it's not so big that it will look out of place on the table top, and it will do for me.

Thankful For Small Blessings

Shock news! The shonky airbrush supplies company I ordered a Badger Sotar 20-20 from way back in January have finally broken down and sent me an airbrush.

Not the version I actually ordered, mind — I ordered the Fine needle/tip, and they sent me a Medium — but at this point I'm prepared to call it a partial victory and just close the book.

Somehow I don't think I'll be doing business with Midwest Airbrush Supply again any time soon. Maybe this is an indication they're getting their act together, maybe it's because I demanded a refund, or maybe it's just a response to the fact that I was making my displeasure known across a range of internet platforms where airbrushery types hung out. I don't know, and at this point I don't much care.

I do have to say, even though they sent me the wrong version, the Sotar 20-20 is a stunningly fantastic airbrush. I'm almost afraid to use it, it's so gorgeous. The finish on all the parts is beautiful, and the action is the smoothest I've ever felt on an airbrush.

I shall have to put some paint through it and see how it sprays.






I knocked up a stand to fit it in Blender.

The STL can be got at https://www.thingiverse.com/thing:3205896

Sculptural Supports

I really like the way Cura's auto-generated tree supports form themselves sometimes.

This one looks to me like those gosh-darned Duke Boys stole th' moonshine truck and jumped it over th' crick agin. Or maybe it's a truck being pulled down to hell by some kind of sand-tentacle-elemental critter.

The model is from m_bergman's 1:100 "LRDG Chevrolet" set. The truck is about 65mm long.

Austin Ten Staff Car

I need some more softskins for my 15mm BEF, and while I was looking through what m_bergman has to offer in that line, I found a set of Austins he has designed. There are various Tilly light trucks, a civilian Austin Ten, and this one, the staff car.

So, now my FHQ senior officers have something comfortable to zoom about in. After all, we can't expect them to have to suffer like the common soldiers.

Regrettably, the layer lines on the front windscreen make it look a bit like it has a venetian blind hanging in there, but that won't be all that noticeable when it's on the wargames table.

BEF Matilda II 1940

 Last night I played an early-war game of Battlegroup with Steve Hoare, and realised that I had neglected my 15mm infantry tanks tragically. Therefore, I resolved to print some more Matildas, in this case the 1940 version with the trench-crossing tail installed, and the armoured Vickers gun in the turret.

I modified the model slightly, both to ease printing and to allow for the addition of magnets under the turret. I also chopped off the 2 pounder and left a socket there, for later installation of a new gun turned from a bit of brazing rod. I got some very visible layer lines on the sloping panels of the hull; I'm printing another one up on its end, which should ameliorate that issue a bit. I'll never get rid of them entirely (unless I get a much more expensive resin printer) but if I can mitigate them as far as possible, I will.







Here it is alongside a Battlefront Matilda II
I assembled and painted quite a few years ago.

Later That Day...

This is the hull that I printed standing up on its end. As I hoped, the change in orientation gave me a much cleaner print, and the top surface detail is quite a bit crisper. Printing the sloping panels in this orientation compresses the layer lines, so the diagonals are smoother — there are still layer lines visible, but they'll pretty much disappear under a coat of paint. Another benefit, though less important from an aesthetic point of view, is that there's a lot more detail in the track links. They're not usually all that visible on the wargames table, but it's nice to know it's there if I want to look at it.

The down-side is that it increases the printing time by about an hour, but that's not a huge deal. It means 7½ hours instead of 6½ (plus another hour or so to print the turret).

2 pounder turned from a bit of brazing rod, using a cheap electric drill as an impromptu lathe.

Tiny Terrain



I'm continually impressed by the level of detail my Ender 3 will give me with its stock 0.4mm nozzle.

This is one of the Ulvheim Ruins pieces I got from Thingiverse (didn't record the url, sorry) shrunk down to 20% for use with 6mm games.

The vehicle is my 1:285 model of the 1930s British Burford-Kegresse machine-gun carrier that I had printed in resin by Shapeways, and the 28mm figure is, as usual, Sergeant Measureby, for scale.

Louca Giant #2 — WiP

I'm very tempted to paint him with a singlet tan-line.
I finally got around to printing the second of the pair of Duncan Louca giants I have. (Here's the first one).

It's scaled to 66%, and printed in eSun PLA+ black with Tom Tullis' FDG Ender 3 miniatures profile, but with a layer height of 0.08mm instead of 0.1mm.

I really like this pair of giants; they look very much as I've always imagined D&D hill giants to look: massively strong, but not gym-ripped, and moronically aggressive. Redneck skinhead giants.

Once the primer goes on, all the tiny printing flaws immediately leap out. I'm getting some very minor layer shifting from time to time, and there's one layer that looks under-extruded about half-way up his feet — it makes him look a bit like he's wearing those creepy toe-slippers. However, the print flaws are minor enough that they should pretty much disappear when the paint goes on.

Flame Skull

I printed Miguel Zavala's Flame Skull, and put it on a clear acrylic flight stand. It's shown here with the ever-reliable Sergeant Measureby and his +3 Spear of 5mm Increments.

I struggle a bit with painting flames and hotness, like hot metal or lava, but I'm relatively happy with how this turned out.

I got a bit of stringing amongst the flame spikes, but I can't say that was unexpected.

Turan I (with added rivetty goodness)

This is the version of the Turan I based on the same model as that in the previous post, but with rivets added.

They are monstrously out of scale of course, but nevertheless I do prefer it with rather than without. The rivets on the original vehicle were a fairly prominent feature.

Turan I (15mm)

This is a Hungarian Turan I of WWII in 1:100 scale, from a model by m_bergman. I've added some track pins to give the tracks a bit more visual interest, but otherwise the model is unchanged from his original design. The figure is a 15mm German from Battlefront.

I've also done and printed a version with some rivet detail as well. Whether it's a worth-while addition I'll find out when I get it painted, but I do like a good rivet on my tank.

With rivets, in the raw white PLA+.
One thing I can be sure of is that they will make painting the turret markings more difficult. Ah, the sacrifices one must make for one's art.

Toldi IIa (15mm)

This is the Hungarian Toldi IIa of WWII. Unfortunately I don't have any Hungarian infantry figures, so these Germans will have to do.

The tank was printed on my Ender-3 in PLA+ using an experimental Cura slicer profile, still being fine-tuned.

Fat Dragon Printing


I watched the most recent Fat Dragon 3d printing video, in which the guy (Tom Tulliss) stepped through his Cura settings and explained what each of them does, and why he chose the settings he did.

I'm not quite as ignorant as I was a couple of months ago, but nevertheless I found it quite illuminating. I thought I'd give his Ender 3 miniature-printing profile a try, to see how it compared with my own hodge-podge. I used one of the Fat Dragon skeletons as a test subject, as they print very reliably without supports.

The mini has been given a very light airbrushing with a pale grey primer so that it will photograph, but no other post-processing.

Overall, I'm pretty happy with the profile, from what I see here. Improvements over my own profile are slight, but definite enough to encourage me to keep using it. Next I'll try it on a 15mm tank model (the other thing I print a lot) and see how it serves for that purpose.

Regrettably, at the time of writing YouTube has gone doolally, so I can't link directly to the video. I'll try again later.   The video is at https://www.youtube.com/watch?v=AqEWl51s9Rw

Later....

As I said I would, I tried the same profile on a 15mm tank, in this case a Hungarian Toldi II of WWII.

 At first glance, it looks OK. I certainly got much, much less stringing than I do with my own Cura profile.

However, all is not well. Not completely, at any rate.
Shell separation

In several places I got significant separation between the shell walls and top layers.

That may be for a number of reasons; for a start, this is printed at a much lower temperature than the recommended range for eSun PLA+ (195° rather than the 205° to 225° recommended by the manufacturer). Also, I think there's a shell overlap option in Cura that it might be worth looking at, if I can find it again.

I shall have to make a little test model to dial in this stuff, something that takes significantly less than 5½ hours per iteration to print.

Duncan Louca's demons, Part Tres

This is the third of three big-mouth demons from a set by Duncan Louca.

I tried a much more chaotic colour scheme on this one than I did on the first two, and I can't really say that it's a great success. However, inertia will no doubt keep it this way forever now.

Duncan Louca's Demons, Part Deux

This is the second of Duncan Louca's set of three demons with exceptionally large mouths that I've painted.

I like his sculpts a lot.

This has been printed on my Ender 3 at 0.08mm in PLA.

Mr Blobby

Model by Franklin Burger:
https://www.myminifactory.com/object/3d-print-46858
I found this model somewhere on the internet, alone and uncredited, so I have no idea who made it or what it is or anything. People have suggested that it's a Kirby, whatever that is, with a human face pasted on.

I like it, and I'll print about a dozen of them, and make up some stats to use them in my D&D campaign in some way.

The original model was only about 1.5mm tall, so I've rescaled it by 1500% to roughly 20mm.

Sculpting in Blender

https://www.thingiverse.com/thing:3148420
I'm in the process of teaching myself a little bit about digital sculpting in Blender. This is the latest fruit of my digital loins.

This poor guy got chained up and stuck in a hole for no other reason than that I failed to plan ahead to making a body and limbs for him. I probably could cobble something together by stretching and moulding from its base, but it wouldn't be ideal.

I've put the model on Thingiverse, both as it's seen here, and just as the bust. I strongly suspect that the chained up version would be quite tricky to print successfully; those chain links are bound to be problematic.

Just the bust
Printed on my Ender-3
at 0.08mm layer height
in eSun white PLA+

Redesigning Models for FDM Printing

FDM (Fused Deposition Modeling) 3d printing is a marvel, and it has revolutionised the way that I make the toys I push around the wargames t...