Fully articulated 24" tall AT-AT adventure

[Hagoth]

Inspired by starks Revell AT-AT WIP upgrade thread seen here Revell At-At WIP this build thread is a spin off to dive further into dissecting the stop motion articulation of the studio models and attempting to replicate what is seen on screen. The premise of this thread is be an open build for all to share and benefit from. Templates and files are welcomed to be shared and modified and shared again for all to use. Insights and examples from other threads and previous work is welcome here including what has already been shared on Starks thread that generated the idea for this one in the first place. The end goal of this adventure will be a 24"-25" tall AT-AT that looks like what is seen on screen and is fully capable of being stop motion animated with movements that replicate what was seen on film. Thoughts of motorizing the result of this project have been considered so there may be a chapter two with this. With various ways of constructing the moving parts and different methods of making them work this is not intended to be a Studio Scale replica with actual donor kits parts or constructed in an identical manner. However, identification of donor kit parts and eventual mapping of them to an AT-AT model is a welcome subplot in this adventure. Wouldn't a poster of such a mapping be really cool to produce? Scratch building, laser cut parts, metal machined parts, 3D printing, existing kit modifications, etc. are all legit construction methods to explore with here.

Let's have fun with this and see what we can do as a community. Everyone is welcome to join this adventure. And, as with many adventures, this one is likely to make one late for dinner. Who knows how long this will take?

 

[Hagoth]

To start off with, parts that will be made to move:

The legs and feet
Articulated toes
Spinning hip and knee flywheels
Moving leg pistons
Moving leg extension motion limiters
Hip joints both up and down and out to the side
Feet with the shock absorbers in them
Sliding foot hydraulics
Rotating cheek guns
Recoiling main guns (spring loaded?)
Moving head and neck

Other ideas:
Opening hatches. doors (magnetic?)
Spinning drive parts (front drive train?)

Anything else to add to the list to make this interesting?

 

[Hagoth]

Here is what has been done so far. anamorphicWayne project Project: Revell AT-AT Walker is the source for the profile templates starting this out. I am in the process of converting the templates onto 3D printable objects and working out the motion of the various parts. The range of motion sequence:

I'm trying to simulate the rubber strap and elastic combination that apparently drove the leg pistons with a curved rack and pinion. once this is worked out a linkage to drive the knee fly wheel will be developed. I know the knee fly wheel was hand animated but I think I can simulate the motion with a link to the piston cam.

 

[starks]

I think you covered most everything!

One thing that popped up on my radar recently was the original concept to have pistons in the hip. When looking at the first walker construct theres two horizontal slots in the hip. Seems this idea was ditched in favour of the diagonal slot and leg limiters.
It would however be interesting to see a hip built based on the initial conceptual model.... as a walker variant perhaps?

Cheers,
Josh

 

[starks]

I'm trying to simulate the rubber strap and elastic combination that apparently drove the leg pistons with a curved rack and pinion. once this is worked out a linkage to drive the knee fly wheel will be developed. I know the knee fly wheel was hand animated but I think I can simulate the motion with a link to the piston cam.

I think if motorising this in the future, as much of this that can operate through its own motion will be important to limit the need for multiple motors and programing of such.
This is going to be great!!
Cheers,
Josh

 

[JediMichael]

This will a cool project, but I'm definitely no engineer, so I'll have to watch from the sidelines.

 

[Hagoth]

I think you covered most everything!

One thing that popped up on my radar recently was the original concept to have pistons in the hip. When looking at the first walker construct theres two horizontal slots in the hip. Seems this idea was ditched in favour of the diagonal slot and leg limiters.
It would however be interesting to see a hip built based on the initial conceptual model.... as a walker variant perhaps?

Cheers,
Josh

I noticed that as well with the hips and the two horizontal slots. I wonder what the intended mechanism was to be used with those? Maybe pistons like you mention. One advantage of the single diagonal slot is that is does open up the option of driving the leg with a single linear motor in that area or a worm gear driven fork rotating around the hip to body joint.

The picture above is of the original ILM prototype used to make the movie models. It shows the two horizontal slots in the hip blade.

 

[Hagoth]

This will a cool project, but I'm definitely no engineer, so I'll have to watch from the sidelines.

Welcome to the adventure JediMichael!
Don't have to be an engineer to help out. Insights, research, and discussion are part of the process.
But then watching from the sidelines is a worthy pursuit as well if an occasional cheer of support is offered!

 

[JediMichael]

Welcome to the adventure JediMichael!
Don't have to be an engineer to help out. Insights, research, and discussion are part of the process.
But then watching from the sidelines is a worthy pursuit as well if an occasional cheer of support is offered!

Anything for an AT-AT thread.

 

[joberg]

Eager to see the next installment of your adventures

 

[starks]

My apologies if this is getting off the main build topic Hagoth. I pulled these from Baloo's thread, I'm sure you noticed them. They show the original concept for scale drawings and show the inside of the early hip with what appears to be the 2 pistons.
also worthy of note look at the size of the figure! That actually would put the Revell kit at the intended scale of 1/53 I believe but no way is the studio live action set fitting in that head. Also seems to state 1/32 scale.

Cheers,
Josh

 

[Hagoth]

My apologies if this is getting off the main build topic Hagoth. I pulled these from Baloo's thread, I'm sure you noticed them. They show the original concept for scale drawings and show the inside of the early hip with what appears to be the 2 pistons.
also worthy of note look at the size of the figure! That actually would put the Revell kit at the intended scale of 1/53 I believe but no way is the studio live action set fitting in that head. Also seems to state 1/32 scale.
View attachment 1465451
View attachment 1465452

Cheers,
Josh

Not off topic at all Starks. Background references like this are welcome. A concept art At-AT would be a cool build. I noticed that it shows the attachment of the hips to the body which is an area I'm looking for more clear pictures from the studio models. Shows a different neck brace system as well. There are some additional detail ideas at the rear drive end I'd not noticed before.

 

[starks]

Not off topic at all Starks. Background references like this are welcome. A concept art At-AT would be a cool build. I noticed that it shows the attachment of the hips to the body which is an area I'm looking for more clear pictures from the studio models. Shows a different neck brace system as well. There are some additional detail ideas at the rear drive end I'd not noticed before.

I found a snippet of an article... may have to find again... that ascertained the legs or maybe the hip used a ball in socket retainer system along with the screw to support the weight of the models as the screws alone must not have been enough to prevent the weight from slowly moving the legs. An important element if doing stop motion over a number of days... or something to that effect.

Edit... I found the article, I will post it tonight. Also seem to have found various kits used so will be a starting point for reference.

Cheers,
Josh

 

[Hagoth]

I found a snippet of an article... may have to find again... that ascertained the legs or maybe the hip used a ball in socket retainer system along with the screw to support the weight of the models as the screws alone must not have been enough to prevent the weight from slowly moving the legs. An important element if doing stop motion over a number of days... or something to that effect.

Edit... I found the article, I will post it tonight. Also seem to have found various kits used so will be a starting point for reference.

Cheers,
Josh

This is a great find. Look forward to reading it. Any pictures of the joint system would be very helpful. It looks like the joint was mounted to the body by a vertical cylinder from the prototype picture and the concept sketch that are posted above. Not sure how accurate the Bandai joint is but it does seem to offer 3 axis motion.

 

[JediMichael]

Being curious to see if I could perhaps find any useful info....I found this video. While it might not help any bit on the build, it is cool to see people putting scientific logic behind things like this.

 

[Hagoth]

Being curious to see if I could perhaps find any useful info....I found this video. While it might not help any bit on the build, it is cool to see people putting scientific logic behind things like this.

Thank you for the contribution! If we ever get to the point of motorizing one of these that just might come in useful as a speed scale comparison. If you correct for the perspective shift in height and the additional height of Lick with his helmet on it could put it at about 30 - 32 meters tall or close to 100 feet.

As another point of reference how tall is a Bandai 144 model and how tall are the figures? Storm troopers were taller than Luke as he was declared "short" for one by Leia so maybe an even 6 feet or even two meters tall?

And on another point of interest I noticed that the range of motion that the mechanical parts seems to be capable of (leg motion image above) far exceeds what we see on the screen at least in the forward direction of the front leg and back wards direction of the rear one. That scene with Luke taking one on is turning into my go to clip for the movements. Has anyone ever measured the degrees of rotation that the upper legs go through? I think I'll have to do some screen captures and figure it out. It may make the travel distance mismatch issues with the piston pulleys resolve itself.

 

[JediMichael]

Maybe this can help now that I think of it.
One thing that someone here on the RPF had mentioned years ago, (do not remember who) is how the feet compress into itself. I have never seen any model or person make a scratch build do this, but it WAS in the movie. I will take some screen grabs to illustrate best I can. And maybe you knew this already, but just incase.....as I would like to see a model do this, even if its the most little simple thing. Looking more into the scene, it appears not every one of the ILM models were doing this. At least one of the normal sized ones and the big leg for smashing Lukes snow speeder was doing it.

Three screen grabs. First frame the foot is not quite all the way down, but 2 and 3 it is, and you can see the top red line, on the 3rd frame, the top of the foot is ever so slightly down.

See it a little better on the bigger foot, which I only recently found that they even had made this.
The camera does tilt down a little as well, and the top is cut off, but is you play the scene, you can tell.

Hopefully I explained it well enough.
When I find out about little things like this, then when I see its not known or in any models or builds, I get obsessed.

....annddddd.......
Heres a motorized version I remember seeing many years ago, (video uploaded in 2008) and I was able to find it.

 

[starks]

Maybe this can help now that I think of it.
One thing that someone here on the RPF had mentioned years ago, (do not remember who) is how the feet compress into itself. I have never seen any model or person make a scratch build do this, but it WAS in the movie. I will take some screen grabs to illustrate best I can. And maybe you knew this already, but just incase.....as I would like to see a model do this, even if its the most little simple thing. Looking more into the scene, it appears not every one of the ILM models were doing this. At least one of the normal sized ones and the big leg for smashing Lukes snow speeder was doing it.

Three screen grabs. First frame the foot is not quite all the way down, but 2 and 3 it is, and you can see the top red line, on the 3rd frame, the top of the foot is ever so slightly down.
View attachment 1465710

See it a little better on the bigger foot, which I only recently found that they even had made this.
The camera does tilt down a little as well, and the top is cut off, but is you play the scene, you can tell.
View attachment 1465711
Hopefully I explained it well enough.
When I find out about little things like this, then when I see its not known or in any models or builds, I get obsessed.

....annddddd.......
Heres a motorized version I remember seeing many years ago, (video uploaded in 2008) and I was able to find it.

The foot has an insert in the base and a large spring inside. The toes are fixed by pins and you will notice hinge up and down also. All 3 hero models were built in this configuration so your %100 correct, the foot does compress

And that walking walker is cool! They got the knees lifting. No cam movement that I can see but what an achievement!


This was originally posted by dsp5500 during his awesome build.

Cheers,
Josh

 

[JediMichael]

The foot has an insert in the base and a large spring inside. The toes are fixed by pins and you will notice hinge up and down also. All 3 hero models were built in this configuration so your %100 correct, the foot does compress

And that walking walker is cool! They got the knees lifting. No cam movement that I can see but what an achievement!


This was originally posted by dsp5500 during his awesome build.
View attachment 1465755

Cheers,
Josh

I have read bits and parts of that, but never the whole thing. Truly amazing what he did, especially for the late 70s, without any of these design programs and 3D printers to help.
Saying the feet were shock absorbers is better wording than compresses. Didn't really know what to call it.

 

[starks]

I have read bits and parts of that, but never the whole thing. Truly amazing what he did, especially for the late 70s, without any of these design programs and 3D printers to help.
Saying the feet were shock absorbers is better wording than compresses. Didn't really know what to call it.

Definitely. A lot of special maching of parts however, something not usually achievable by the general modeller. Computer modelling and 3d printers are becoming better and better so its making so much more achievable for the general public to have the opportunity to reproduce pieces.

The walkers in the Hoth battle are amazing and it shows how much that design paid off in aiding the animators.

Of note the original with the horizontal hip slots was confirmed as just the prototype and the 3 heros created from that design.

Cheers,
Josh