Engineer Puppet (Halo 3: ODST)


405th Regiment Officer
Member DIN
Right now I'm in the magical land of Timbits where I’ll attend my first international convention – Ota-Ota-Otafest in Calgary. And if I’m going over to meet the goofiest goofballs on this planet, then I need to bring something equally insane.

Luckily for me, insanity is a lifestyle.


So, I’ve made a Halo 3: ODST Engineer Puppet! It's name is Smaller Than Average, though it's much for fun to call it Lumpy Space Princess. It's smaller than what they are in game, because I need to fit it in a suitcase and full sized alien puppets aren’t the easiest to travel with.

To try and keep everything as organised as possible, I’ll be breaking up the build thread into multiple sections, and adding updates over time.


Head and Eyes


As always, if you have any questions, please ask away! There's a lot of techniques and mistakes I haven't elaborated on this thread because of the complexity of the build.
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Although this covers the general build, I wanted to make planning its own section to show how important it is, especially for when it’s something that has rarely been done before.

Planning for the puppet started on my Holiday break in late December back in ‘23 (not ‘63). The obvious first step is research, of course. Looking at reference photos and going “is this viable?” “How can I recreate this functionally?” “Why did I sign myself up for this?” Knowing that Saber has also made an Engineer before, I looked through her build thread at some of the approaches she took to making different components.

Using a game model of the Engineer from the Halo Archive, I was able to get a really good look at the shape and proportions of the astro lollipop in Blender which will help down the line. It's worth noting though, that I later found that due to how differently it's rendered in 3D software, it's important not to rely too much on it for colour references - best to look at in-game content for that.

Once I started to get a grasp on how to tackle elements, I broke it down into a list of how to generally do parts, and how to break it up for transport/ease of construction. Keep in mind this list changed drastically.


Then for parts like the eyes and sacs, I drew up diagrams on Inkscape of how they would work. These diagrams changed A LOT as I learnt through good old fashioned trial and error, and even now they don’t entirely represent how the mechanics work (which is why I’m showing them in the planning section).


When I’m imagining mechanisms and they get too complicated, I like to clean the slate and start from scratch. What are the bare essentials they need to do, and how can I keep it simple? Then once brought back to the basics, I expand until it gets too complicated – then bring it back. It’s a kind of cycle that over each iteration, the system gets more straight forward and easier to tackle.

While I was sifting through different ways of approaching challenges, I was lucky enough to have groups like the 405th, Lumin’s Workshop and the Stan Winston School of Character Arts forums to help me out!
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The very core of the build is the structure of the body. Using the Engineer game model, I created a sphere and distorted it to fit the shape of the body, neglecting the sacs for the moment. This was UV unfolded, then turned into paper templates in Plushify which was then transferred to 6mm foam. This made it lightweight yet still strong enough to retain its shape. A removable PVC pipe sits in the center so that it can push out the shape of the body (and give me something to hold), and come out so that the body can compress for travelling.



The sacs are made from a high density upholstery foam. They are created by cutting it out into a (very) rough circle, cutting about 20mm from the top and then shaping it crudely with scissors. The inside is gutted from the bottom, and trimmed as thin as I dared to give the foam the most flexibility possible with little resistance when deflating the sacs. A printed axel, with an EVA foam washer is inserted (to stop the plastic cutting into the upholstery foam), which contains a hole through the bottom in which fishing wire will feed through. The top section is glued back on with spray adhesive, cut back, and it’s all then rounded on a belt sander. There’s three large sacs, six medium sized, four small and one under the front armour that is non-functional.


The mechanism inside works simply by pulling on a printed ring connected to some 0.6mm nylon wire, which pulls the foam sacs inwards. The natural elasticity of the foam pulls it back out. The rings are slid over an old knitted glove, with Velcro-lined rings on the fingertips to stop the other rings slipping off. This allows me to slide on the glove (not too easily, mind you) and put the rings straight on, without fumbling trying to get them on the right fingers. Originally I had it so my hand was palm-down inside, sitting under the internal bracing, but later found that having my hand palm-up made working the sacs easier, and was much less strain on my muscles.

On the line between the finger rings and the sacs is another ring with three extrusions that allow me to install a small screw. This is a tightening mechanism; I can roll this up to shorten the length of the line, then add a screw to stop it from being undone.


Since this was my first time using upholstery foam to make a creature, BJ Guyer’s array of puppetry courses on the Stan Winston School was extremely handy. One trick among many I picked up is to use a sanding disc on your rotary tool to shape and carve the foam. By doing this, I was able to cut in the lines on the sacs.

They were initially glued on to the body with contact cement, then pinned down and further glued with E6000 for an even stronger bond. Protip, I made sure to use not-white pinheads so I would easily notice if I left any behind.

Further details were burnt in with a soldering iron. And by the Nine, of all the things I’ve burnt for cosplay, upholstery foam is by far the stankiest!

The next step was painting the sacs. For this I used Design Master spray paints – heavily pigmented and flexible. I used Ice blue and Black cherry for a stark contrast in colours (my colour reference was moreso based on how the model appeared in Blender, rather than in game, which not only is quite dark but is very difficult to get reference images). This same paint was used for the tentacles and head. Some watered down blue acrylic paint was applied to add the glowing spots.


Once dried, I use lots – lots – of rolled strips of foam clay, looping them around the sacs and on the sides. Using different sizes and patterns gives it some variety, and to eliminate flat spots, I Dremeled in some texture where the clay didn’t cover spots.


After sealing just the foam clay with Mod Podge, I mixed some black and white paints to make a dark grey and carefully painted that on. The divets in the sacs were spotted with light blue paint, and all the crevices were then airbrushed with black for shading - same with all the upholstery foam pieces.



The tentacles are again upholstery foam, cut and sanded to shape with lines scored in using a Dremel like described above. One important thing with puppets is to generate movement without having to physically control it yourself. I think the name varies but I've heard it called Implied Motion, where parts like extremities, fur, antennae etc. can move freely and loosely without the puppeteer having to put in any extra effort. This can really add a lot more character to the creature. So with the tentacles, I slit the bottom of them and added in three fishing ball bearings to each one, attached with just hot glue. This extra weight means that instead of the foam being stiff when it moves back and forth, the weight adds resistance to the motion, allowing the tentacles to curl and swing back and forth - as demonstrated:


Like the sacs, the tentacles and the tail got the same gradient treatment of spray paint, then the lines were painted with the airbrush.


The feathers used were dyed ostrich feathers, stripped down the center with a fresh blade and using a cut tapestry tool, were pushed and glued into the back tentacles. Because I was travelling internationally with this puppet, I cut all the segments before leaving but left them separate for travel. That way, if there was a customs issue on bringing it into another country, they would only dispose of the feathers and not the entirety of two tentacles. They're a little rough, but it's a tricky, time consuming job, especially considering this was done in the hotel room.




The *ahem* “kilt” was patterned up with an old catalogue with the armour attached to the body. This was transferred to some cheap black fabric, sewn together and holes/slits were cut. The edges were burnt with a soldering iron to not only stop the fraying ends but also makes it look cauterised. The fabric was given a dusting with charcoal spray paint, then tipped with the Ice Blue Design Master paint (albeit it just looks grey and I didn't get 'round to hand painting it before leaving).

The kilt is attached by sliding it over two screws on each end of the armour.
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Head and Eyes​

Eye Mechanisms​

I knew I wanted the eyes to blink to give the character a lot more expression. Like explained earlier, the eye mechanisms changed a number of times. Lots of trial and error was done to get the right shape and placement of components for proper rotation and minimal resistance.


The eyes work through another fishing line mechanism. As the string is pulled when the trigger is squeezed, it pulls the eye on the opposite side of the pivot point, closing the eye. Some gears behind the eyeball also force close the bottom eyelid at the same time. Springs attached to the top eyelid pull the eye back when releasing the mechanism, thus also opening the bottom one again. Some rubber tubing allows the line to slide through the holes in the eyeplate. To be able to adjust how closed the eyes are (and make sure they are all closed at the same time), the line was tied and glued to some screws on the "trigger" component, which when rotated, wraps the line around, tightening it.

I’m lucky to have SgtSaint live close-ish enough that he was able to resin print these components for strength. Interestingly enough however, I think with the gear mechanisms being resin printed vs FDM printed, they actually became too accurate and I couldn't get them to work as well this time, so for the moment I had to default to the prototype eyes, which unfortunately means I couldn't get the shine that I did on the resin ones. Once I re-figure out the gears, I'll switch over to the resin ones.

Another problem with the gears was that my idea for an axel was to use a segment of filament. Which would be fine, except that it comes off curved due to it conforming to a roll. This meant that as the axel rotated, it would actually not just roll the gear but move it around. I'll likely use something like toothpicks in the future instead. Frankly it's a miracle the prototype eyes even work!

The prototype eyes were activated by pulling down on a piece to draw the strings. The current iteration, to make it a one-handed operation, uses a trigger mechanism, one I've used for a number of years (though probably need to move away from now). I knew before making it that because some of the tuning pegs were closer to the pivot point, they wouldn't pull on the strings as much as the ones further away. This was fine, as long as they were all tuned to be closed when the handle was fully closed.


Head Form​

Like the sacs and tentacles, the head too was upholstery foam and was constructed/painted using the same methods. Unfortunately I had to add some extra volume along the sides, so I could add the wriggly parts that look like a flatworm - which means there are seams at the front (shhhhh).

The head was cut in three pieces initially to allow for a cavity for the eye mechs. The internal section of the middle piece was hollowed out to allow it to curve more easily. The eyes sockets were cut out with a sharpened PVC tube, and before glueing the top section of the head on, some EVA foam was inserted to pull the sides into shape. I'm still unsatisfied and concerned with how thin the leftover upholstery foam is around the eyes, so I need to find a way to reinforce that without getting in the way of the moving eyelids.




The antennae are made by wrapping two brown pipe cleaners together (aww yea, primary school craft supplies) and gluing them to the face of Velcro, which is how it attaches to the head. The top features a short-cut ostrich feather, spray painted with the same red as was used on the foam, then brushed to stop it from sticking together. And like the upholstery foam, the head got the paint gradient and airbrush special treatment. Some red was then brushed onto the sides and under the eyes.



As you can see, a hole and seem were cut on the bottom section of the head. All these parts are held closed with magnets, which were attached with E6000. The head attaches to the body with three screws.
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I can say with full confidence that the models of the armour are what I call a "topological gorefest". I originally designed the armour to be made from foam, but then figured it would be quicker to just print it. The downside is, though, that a lot more weight is added to the puppet. So the reason for the bad geometry was me converting it from foam patterns to proper 3D models, and not giving a proper darn for how the geometry was (time constraints), as long as it looked good.

Some models were split apart in the slicer so they had a flat surface to sit on. It meant cleaning up a seam, but it also meant fewer ugly overhangs or bridges. For these parts, a cavity was Booleaned in so that when it was split and printed, a paddle pop (ahem, "tongue depressor") could be inserted so the piece is aligned. I like to keep the brims on and superglue over the edge of them, giving me some extra material to sand back, instead of having a seam line caused by a cavity.


The banding on the sides were simply made of EVA foam, as the flexibility and ease of cutting made it much easier to adapt the patterns for each side (as because of the size/placement of the sacs, both sides are not completely symmetrical).


Because of all the shapes pointing out in any direction they want to, parts were designed individually so they could be screwed together. I was a bit silly with the first few parts I made, as I didn't design them so that the nuts that the bolts screw into had a proper place to sit. I thought I may be able to rely on "heat insetting" the nuts in (heating up the nut and forcing it into the print, melting the plastic) but this has numerous downsides:

-It's not as accurate when you try to line it up
-With a hollow body, if you inset it too far, you can easily lose the nut in the print
-With nothing to hold the nut on both the top and bottom, when you screw the bolt in, it's easy to actually screw the nut out of place, if you don't seal it in place

In fact, the two wing-like pieces are only attached to the front panel via screws but no bolts, just holding on to the plastic. This is unreliable however, and it's very possible to re-thread the plastic slot, making it lose its grip over time.

So after these initial pieces, I modelled in slots to hold the nuts, and also printed thin caps that sit over the bolt and glue onto the plastic either side.

All of the conjoined printed sections attach to the puppet's body via more screws, with printed washers on the other side to prevent the screws slipping through the foam of the body. The foam bands have magnets which hold them to the front and back sections, but moreso rely on the compression of the middle section on the sides to hold them in place. The neck armour is all attached together with elastic, and is Velcroed to the front of the neck and pinned to the back. And finally, the front panel over the sac is held onto Velcro, sitting on an elastic band.


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The painting on the armour was done in what I now like to call "The Buttercup Method", because you build it up just to let it down. AKA, subtractive weathering.

Once the prints are fully sanded, a flat black primer is sprayed on. I like flat/matte because glossy takes too long to dry, and I don't need this paint job to be glossy.

Next, two layers of a metallic are applied. Two coats gives it a bit of extra thickness to reduce the chance of going through it. After this point, two clear coats are applied (and remember to test your paint compatibilities!)

Next is the "final" layer - in this case, a Rustoleum chalked charcoal grey, one of my favourite spray paints. Once that's dry, it's time for the weathering.

Weathering is achieved with ahem one grit sanding. In other words, literally scraping it with a brick. There's a number of reasons why I like using a brick:
  • The inconsistent surface adds scratches in different ways
  • Using a large object like a brick makes it harder to reach into crevices where large debris would be unlikely to hit
  • Sometimes, you can get dirt off the brick to rub on to the part, so extra weathering!
This is the method on a piece for a different project:


After that, I used a needle file to go over the edges of the grooves and any extra edges I wanted to highlight, and some sandpaper to clean up any bits of debris left.


Like the rest of the Engineer, the armour was airbrushed in the crevices. However, I think the paint wasn't pigmented enough (instead of using airbrush paints, I diluted acrylics with Windex), so even after a couple of coats, the shadows are quite subtle.
Before and after:

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I'm excited to see how you did the rest! Looks amazing
Your puppetry skills always amaze me! This turned out so good! Looking forward to seeing the rest of your process!
Fraking awesome
Cheers pals!

I've updated a couple more of the posts, and hope to finish the painting section in the next week or so. I'll also add some more pictures of the armour disassembled once I strip it bare naked after the convention.
I won't post any of the pictures that I have yet so that PlanetAlexander can be the first for the whole reveal. I will say however that this turned out amazingly! It was so cool to see it in person!
You're so considerate, here's a smooch

More media will come through once I get back and the tears stop rolling

From the few photos I have seen; you have killed it with this build, wow! :love:
Thanks Kae!
Having the sacs actually move is wild man, amazing work! Would be fun to have accessories to go with it such as a fake zippo, maybe the bomb jacket (rip) and possibly, just maybe...a tiny hat.
Having the sacs actually move is wild man, amazing work! Would be fun to have accessories to go with it such as a fake zippo, maybe the bomb jacket (rip) and possibly, just maybe...a tiny hat.
Ooohhh I do have an idea...

Also, the painting segment is now done! When I get the time, I'll create a new section to go over what I need to do before the next convention, including repairs, upgrades and possible additions.
I'm in awe. Thank you for breaking your process down so thoroughly, this has really given me some better insight into your craft. Does he have a name yet?
Always love doing writeups for projects, because not only can it help others, but it helps one's self reflect on the work too!

It's official name is Smaller than Average, but you can also call it Lumpy Space Princess.

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