Stop motion: How to choose the right armature

How to choose the right stop motion armature for your puppet

Ok, so you’ve done your puppet drawing, you’ve nailed down your story board and perhaps even your animatic and you can’t wait to start animating! Apart from getting all those props for your stop motion set, you need to get the armature for your character but where do you start? Wire armature? Ball and socket armature? Threaded lollies? Nuts? It can get a bit confusing so, How to choose the right armature for your stop motion puppet?

As with everything, there isn’t a single right answer. The best answer is: “it depends”. It depends on what you’re trying to do and, of course, your budget. So let’s cover few scenarios and see how you can approach each type and whether is the right stop motion armature for your animation.

Types of armatures

Armatures wire, ball and socket and 3D printed
Armatures wire, ball and socket and 3D printed

If you browse the online market for armatures you’ll find all different sorts. From just a few pieces of wire with some nuts to highly customised hand-crafted machined metal armatures. Each type of armature has its rightful place whether for budget or for the type of character on your story. With all this in mind, which are the main armature types? Here’s a list:

  • Wire armatures
  • Ball and socket armatures
  • 3D printed armatures (early prototypes)

Wire armatures

Wire Armature
Wire Armature

This is the cheapest and perhaps the easiest to build, unfortunately also the fastest to break. You can buy a length of wire at your nearest hardware store and with your hands (or to make it easier, with a pair of needle nose pliers), you’ll get a nice and simple skeleton for your stop motion puppet.

This type of armature is great for beginners. It’s simple and really cheap to get going. But as we mentioned earlier, this armature will break very soon after a few bends on the joints so this is not a good choice for a long production or if your character has to do many movements (like running, for example). Having said that, this would be a great choice for those “background” characters or fill up characters as they just move a little and they would be really cheap to make.

Wire armatures are great because they don’t give you any restrictions at the joints (although this can be an issue because some joints in a human body have restrictions like the knees) and you can achieve very thin characters at very small-scale.

There are some online suppliers that sell pre-packed wire armatures, so if you want to save the trip to the hardware store, you could get one of those. And some even come with a piece or two that contain a rigging point and tie downs. (More on rigging points and tie-downs later on this blog post).

Ball and socket armatures

Ball and socket armatures
Ball and socket armatures

These are professional style armatures. They are built to either standard sizes or to custom sizes. These armatures are made for long productions. The joints will last for a very long time, you just need to tighten them up to your clamping need or taste as with movement and over time, they will become a little loose. This also means that you need to make a small hole on the puppet’s skin to access the screws.

They can be made of different types of metal such as mild steel, aluminium, stainless steel, brass, etc. They tend to come in standard sizes such as 9″ or 12″. You can normally buy them “ready-made”, which means they are already assembled and you just need to tighten the screws and you’re good to go, or as “armature kits”, which means they give you all the parts and you put it up together yourself. In this case, you can save a bit of cash by buying an armature kit and, in most cases, it has some flexibility to build it outside of the standard sizes. If custom-built, then the size is up to the customer’s design and choice!

Within the ball and socket armature world, there are different ways of manufacturing them: Laser-cutting, machining, Sintering and 3D printing are the most common. Normally the parts are first designed on a computer using a CAD software. Being able to design the parts on the computer allows for testing the parts digitally first to ensure it’s fit for purpose. However, some of the armatures are completely hand crafted and no software is involved in the process.

Stop motion armature with hinged knees and elbowsLaser cutting is used in all sorts of industrial metallurgic applications but can also be used for other purposes such as laser cutting wood or for the parts of a stop motion armature. With this method, the stop motion armature is first designed on a computer, then the parts are cut on the metal of choice to a very high precision. After some tapping, soldering / glueing and with some balls, nuts, threaded lollies and a bit of hand-forging you have a stop motion armature with professional qualities. This technique can provide a professional level armature at a lower price than other Ball and Socket armature manufacturing methods.

Machining is a combination of methods to convert a raw piece of metal (or wood, for example) into the final desired piece by subtracting parts of it. If done in great (huge) volumes, special machines are designed to make the pieces, like for example to make screws, which are done in the order of millions at a time. But when it comes to smaller volumes (like the ones needed on armatures, about few hundreds or so), then it’s a more a manual process that requires the use of different tools such as drills, etc. As in laser-cutting, it also requires hand-forging, tapping, shaping, etc. This method, if done right, will produce an armature with the least amount of parts, which means less breakable points. Also it will allow to design connection points on any of the sides and not limited to the top or bottom like on laser cutting. They can be designed to eliminate completely the step of gluing/soldering. This method is quite special and requires some great skills.

Sintering is a manufacturing method that compacts and forms a solid mass of material by heat and/or pressure without reaching the point of melting (liquid form). This process can produce materials with different properties, like increasing the strength of the material, conductivity, etc. This method allows to obtain complex shapes directly from the compacting tooling without any machining operation and it weight less than other methods, which means a lighter armature. When it comes to your armature, this would be an ideal method of manufacture as you can obtain the exact design with just the sufficient parts, with the properties needed (anti-rust, magnetic, etc) and with less weight than other methods, but as you can guess, this does not come cheap. A more specific type of sintering is the Selective laser sintering, or what’s commonly known as 3D printing on powder (see below).

Here at Upuno we normally use a combination of laser cutting and machining for all our armatures, however we do have the skills, experience and know how for designing and producing armatures and parts on any of the manufacturing methods mentioned above (and below!). We have many years of mechanical design behind our backs so we have the skills and know-how for any type of mechanical object, from complex rigs and metal structures to tiny little armatures with all the movements.

3D printed armatures

3D Printing is an additive manufacturing process which will produce a 3D object where successive layers of material are laid on under the control of a computer. This method also requires the use of a CAD software to produce digitally first the object you’d like to print. In stop motion is a very recent addition, in particular to aid with face replacement using selective laser sintering (3D printing on a special powder). Within stop motion, it was first used in Laika’s feature film Coraline where the faces of the characters were 3D printed on powder and used for the many characters. It has since been used in other feature films such as Paranorman and the Boxtrolls or the Aardman’s feature film The Pirates! In an adventure with Scientists. When it comes to stop motion armatures and in particular to its joints, this method is not yet strong to hold its own weight on the different postures. However, for prototypes of armatures or full characters it can be the perfect choice.

3D printed stop motion armatures
3D printed stop motion armature
3D printed armature
3D printed armature

Now, we’ve covered the main types of armatures and a bit of the manufacturing processes involved. Hopefully with that information you can decided which one is the right one for your animation project. Let’s say that you’ve decided to go for a ball and socket armature, what features should you be looking at?

What to look for in a ball and socket armature?

You want your armature to make it easy for you to animate it but with so many things, which are the ones you need to care the most? Let’s have a look at some of the features that are important when selecting the right ball and socket armature for your animation project:

Check that the armature has the correct size for your character

That’s right, check the size of your character. Check not only the hight, but arms, legs, hips, etc. Have your character’s drawing and measurements at hand when you’re checking the armature you want to buy. You need to check how big are the joints on the armature because the size of them although it may give you stronger joints they may limit your character’s design. Sometimes if you need a narrow knee or wrist some armatures “force” you to increase the size of the whole puppet so the joints are within your design. This will increase costs of the whole production as all props and sets need also to grow accordingly (normally you’d like to have all things at scale).

Stop Motion armature kit male & female
Stop Motion armature kit male & female silhouette

On our armatures, the joints fit inside a standard 9″ and 12″ humanoid as you can see in the silhouette drawings on our website (and included with the armature packaging). Maybe it’s a bit tight on the 9″ woman (Lisa) but by the time you add shoes it should still fit OK.

Check the type of connections (rod to ball and rod/ball to plate)

The type of connections will tell you how much maintenance the puppet will require from the armature point of view. Once your puppet has been finished, adjusting the connection points or fixing them can be extremely difficult if you don’t want to damage the puppet’s exterior. Connections can be soldered, glued or screwed. If glued, make sure that the glue is of the type of high strength threaded locker so that it will last very long, if soldered, then check it has been soldered correctly as re-soldering a piece will require disassembly and potentially replacement. Some suppliers provide their armatures with what we call “threaded lolly“,  a ball and threaded rod made as a single piece of metal, which means you don’t have to solder/glue the ball and the rod. This would be better as a choice for the connection points as they will never become apart, however ball and threaded rod correctly glued / soldered should be good too.

Hinged vs ball socket knee/elbow joints

Laika's Boxtroll puppet armature
Hinged elbow and knee from one of the armatures used in Laika’s “The Boxtrolls”

Not all joints in a human move in the same way. Ball and socket armatures can mimic many of them but there are some that are more of a hinged movement. If you check how your knees and elbow move you will know what we are referring to. So in order to achieve more natural movement a hinged joint may be more effective. If you agree on this you may want to get an armature with this feature. Here’s more information about the difference between hinged and ball and socket joints. Hopefully this will help you choose the right type of joints on the armature for your puppet.

On our product range we offer both options at different costs for you to decide what works best on your puppet.

stop motion armature knees
Stop motion armature knees

Check the number of joints

You may want your character to mimic exactly a human being so it’s important you choose an armature with all the needed joints. Some armatures on the market lack movement at the shoulders and toes or other areas. Ensure that all the movements your character need to do can be achieved with the armature you’ll buy.

Check exchangeable points (hands, head)

Hands are probably the piece that will break sooner, so you need to be able to change them without breaking up your puppet. Interchangeable hands will be ideal in an armature. There are different ways of making interchangeable hands. Many systems are very similar just check you can easily replace hands as and when you need it without compromising you puppet.

Also it’s common to have hands in different configurations aside (half-closed, fist, OK fingers) so you don’t need to animate all fingers continuously. In this case an easy way to replace your hands is key.

Stop motion armature Hand replacement
stop motion armature hand replacement

Some of our armatures come with hands, the replacement mechanism within and instructions on how to use them. And if you need to create your own replacement wire hands, we have a tutorial on how to do this. How to make wire hands. Ball and socket hands are possible but they could be bigger.

You also need a replacement mechanism for the head. Sometimes because the head breaks or you need to replace the head for another one as the character has changed hair style or is wearing something different.

Replacement hands and head are very beneficial when making the mould of your character for later filling it up with the skin. Making a mould without head and hands it’s a lot easier (almost common practise). Sometimes you also want different materials for your head and body. Flexible for your body so you can pose it and hard for your head so you can make mouth replacement. In this case to fill your mould with two different materials will be a challenge so to separate head from body will be the way to go.

Our ready-made armatures come with easy replacement mechanism so you know you’re covered on that front.

When it comes to feet, you may also want to exchange this. This tends to be a less imperative requirement. Again, check back on your character and decide whether this is a feature you need or not.

Our armatures do not have easy replacement foot but we can design and produce replacement foot if you wish.

Check the rigging points and tie down points

You want to make sure you can use your puppet in any position your animation requires (jumping, flying, running…). For this, rigging points and tie down points are essential. We think the more the better as long as they don’t compromise your puppet’s design. You should have at least one rigging point in either the pelvis or the chest and a tie down point on each foot to steady down movements.

Stop motion armature tie down
stop motion armature tie down

There are different types of rigging connections. Usually armatures on the market either have square shape connexion or tapped hole rig points. Square rigging points are easier to use and lock but can be more difficult to manufacture (cost implications). Tapped holes are harder to use and if a simple rod is used then it’s difficult to stop them rotating. For this reason we redesigned our tapped rig end connexion on our rigs so they don’t get loose. More information on this can be found at the bottom of the blog post Stop motion rigs.

Stop motion square rigging point for armature
stop motion square rigging point for armature

Our armatures have 8 rigging points between the chest and pelvis (5 square shape and 3 tapped holes) and 4 tie down points (normally, for each foot, one on the heel of the foot and one on the toe mound), plenty of choice!

Check the material it’s made of

The material the armature is made of is important too. You want one that won’t rust over time, that stays smooth for as long as possible (reduced galling) so that the movements are still soft and natural. You may want your armature to have magnetic capabilities so that you can use magnetic tie downs too or attach other accessories.

Common materials used for armatures include mild steels, stainless steel, brass and aluminium. Using a combination of any of them will be good to avoid galling but there are other limitations:

Mild steel rust over time so re-using the armature could be a potential issue. It has magnetic capabilities (they can be attracted by magnets) and it’s the most cost-effective of the above list. The rust problem could be solved by applying a surface treatment (paint, zinc plating…) to the armature but this increases cost and paint can chip away.

Stainless steel doesn’t rust and some types of it are stronger than mild steel but only a few have magnetic capabilities. Usually balls are made of stainless steel so if the armature plates are also made of stainless steel the galling problem can become an issue unless the correct type of stainless steel it’s used. So make sure your chosen supplier has made the right choice of stainless steel. Another way to reduce galling will be to apply a hardening treatment to one of the materials in contact (usually the ball so it stays spherical) but this will increase the cost of manufacturing.

Alumium and brass are a good option as they don’t rust and together with stainless steel balls you should have a nice smooth movement. The issues with these two are that are quite soft so manufactures will need to increase the size of joints to minimise bending when clamping. Also no magnetic capabilities here. When we tested aluminium plates we had issues with the threaded M3 holes as they were destroyed after few minutes. For us aluminium was too soft to hold very thin walls as created when a tapped hole is made.

Here at UPuno we use stainless steel because it has all the benefits and we minimised the issue with galling by using a type of special stainless steel that interacts good with 304 and 316 stainless steel typically used for the balls. And also the stainless steel used gives the plates magnetic capabilities.

So, in summary:

Depending on budget and purpose of the armature you may want to choose a wire or ball and socket armature. If you opt for a ball and socket armature you need to check:

  • The armature has the correct size for your puppet
  • The number of rigging and tie down points are enough for the movements you need
  • It’s easy to exchange hands and head
  • The quantity, type and quality of joints
  • The material is made of

There are other factors too, of course, but we think these are the main ones you need to be looking at. Is there something else we should have talked about here? Then please, let us know!!

Happy animating!

UPuno Team

3 thoughts on “Stop motion: How to choose the right armature

  1. Everything I have seen so far uses stainless steel, I didn’t know that soft steel armatures exist. I need to a magnetic type of armature. Do you know where I can buy soft steel ones?

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