Ithorian: Head movement

Another reference image, this one is a min-bust from Gentle Giant

Several RL events conspired to throw off my scheduled on the Ithorian costume. A work trip to Australia took 10 days, and then the worst cold I've ever had took another week. Reviewing my schedule, I've finally decide that I'm not going to be able to finish the Ithorian costume before SDCC 2014. I'm sad about it, but it does reduce the pressure and lets me redesign the costume as I run into problems and look for alternatives. Instead, I'll unveil it for the 2015 con season.

However, I'm not stopping work on this. The additional time just lets me make the costume even more awesome! For instance, I've been following the Giant Creature build by Legacy Effects, Stan Winston School, and a variety of partners. This week, they were showing off the mechanical controls the puppeteers will be using inside the creature. That inspired a new mechanical control mechanism for the Ithorian's head. Also, I've gone a bit overboard on images for this part of the build.

The key components in the mechanism are these ball joints that I bought at a radio-control hobby store. They are used for attaching control surfaces in model airplanes to servo motors. They're solidly built, have smooth movement, and are relatively cheap. I built them into "thrust rods" using threaded rod inside aluminum tubes with a ball joint at each end.

Cleaning up the ends (really, I just wanted to get a shot of grinding steel with sparks flying)

Interrim construction of thrust rods showing ball joints attached to a threaded rod inside an aluminum tube

The steering arm is an aluminum rod passing through a 45 degree PVC joint. The arm has a threaded hole in the middle so that a bolt can hold it in place. Also, the ends are threaded so that the ball joints on the thrust rods are bolted into each end. Here's a more thorough sequence of pictures showing the construction.

My chop saw cuts the aluminum rod to length

Drilling holes in the ends that will be threaded

Clearance hole drilled in the 45 degree PVC connector joint and another clearance hole for the lock down bolt

The ball joint at one end of each thrust rod is screwed into the ends of the steering arm

Sanding down the ends to clean up the rough cut

Drilling the lock down hole that will be threaded

Lock down bolt screws into the threaded rod locking it on the PVC joint

The steering mechanism is installed so that the left/right axis is mounted into the forward/back axis (shown with the counterbalancing springs)

The drive levers are mounted on each side of my head. They are made from aluminum stock and cut to size for my head. A pivot hole is drilled at one end and used to mount the lever onto the outside of the frame. There's also a threaded hole used to mount the other end of the thrust rods. These are the basic head movement controls.

The lever arms cut to size, a clearance hole at one end and a threaded hole for the thrust rod attachment

The pivot point on the lever arm is loosely bolted to the frame, and the thrust rod is mounted to the lever

Since the lever arms are going to be "attached" to my head, all ends are rounded and deburred

Mechanical assembly is complete, and the lever arms control the neck assembly (left/right and up/down)

A headband loosely attaches to the lever arms so my head motion can drive them. I sewed the basic headband from strips I cut out of an old t-shirt along with some Velcro fasteners, and then I attached EVA form for padding. Some canvas strips are sewed down to wrap around the lever arms. All of this was sewn with our old Necchi sewing machine (sorry, no pictures). That thing is a work horse. At the end, it had to sew through 2 layers of canvas, the EVA foam and two layers of t-shirt material. Tricky, but it got the job done.

Finished headband showing the Velcro fasteners and the padded straps that wrap around the lever arms

The canvas straps on the padding wrap around the lever arms. The arms can move up & down inside the straps and have some room to twist.

The parallelogram structure of the overall mechanism translates my head motion to the head movements of the costume. It's pretty slick. Here are some pictures of me testing the rig. I was checking fit, range of motion, and looking for high friction joints.

The mechanical structure is mounted in the FX corset. The headband is firmly wrapped around my head for controlling the neck/head mechanism.

Checking some range of motion, my head is straight up in this shot. I can tilt my head back and forward as well as turning left and right.

As I bend my head forward and turn, the eyes turn and bend down as well. All the movement is in the neck joints. The eyes themselves are not turning.

I tried to limit my motion to just tilting my head down. The costume head followed pretty well. This isn't the full range. I just couldn't coordinate the shot well.

The rig is comfortable and the range of motion is pretty good. The problem I found was in the azimuth rotation around the neck (left-right). I need to find a lower friction bearing. But overall, I'm very pleased with the movement.

Okay, one last photo. So far I haven't shown the outer structure. I've been making some major changes, so a lot of the foam structures I've previously shown don't fit anymore. Here's what's left of my original foam outer layer on top of the current mechanism. It gives me a feel for the proportions with my head covered. There's lot's of room under that "hump", so my head and all the controls fit comfortably. I'm pretty happy with the overall proportions.

My head will be completely covered, and the rest of the structure has a good profile for an Ithorian.

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Ithorian: New approach to the eyes

Another reference photo of Ithorians, in this case Senators in the Republic

Okay, I took a break from working on the Ithorian costume so that I could rethink some approaches. In the meantime, a new tutorial came out from Stan Winston studios, the third part of a series on making a T-Rex character. It's a vehicle for demonstrating a lot of foam construction techniques, but part 3 covered making the eye. That was the inspiration I was looking for. So here's where I've gotten so far.

For this version of the eyes, I need to get a couple of clear plastic half domes. I liked the size of the 4" Styrofoam balls I used in the first attempt, even though I didn't like the material. So I cut one in half, turned a 4" disk as a base support and glued them together. Then I covered the shape in Spackle, filling all the gaps and sanded it smooth. I used that structure as a buck (the mold) in the vacuum form machine (sorry, no picture of this stage). I then pulled a form using a sheet of 0.060" styrene.

That first pull was terrible. There was a lot of webbing (folded plastic) and the texture of the Styrofoam was revealed, making the surface all bumpy. So I left the plastic on the buck, cut the webbing away, and did some sanding to try & smooth the surface. I also researched methods that other folks use to reduce webbing on vacuum forms. Using a wooden block to raise the height of the buck and a cardboard ring to force the melted styrene down around the buck, the second pull had no webbing, and the surface texture came out better. Still, I left it on the buck, sanded the surface, and pulled another form.

The final buck after 4 layers of plastic and followed by sanding

It took 4 pulls, each sanded smooth and left on the buck, before I was pleased with the surface and the shape. At that point I moved onto the the clear plastic form.

Clear plastic vacuum formed around the buck using techniques that forced any webbing off of the desired shape

Here's how the clear plastic looks after the pull. The buck is elevated on the wooden platform and the cardboard ring was used to push the plastic down around the buck before applying the vacuum. These are the important steps needed to eliminate webbing on the desired part of the form..

Plastic cooled down and removed from the vacuum former

There's a lot of plastic that needs to be cut away from the plastic dome. You can see the wooden stand is still captured in the plastic, and you can see some webbing down on the base of the plastic, well off the critical dome shape.

Using a surface gauge to score the plastic

Next, most of the flat plastic waste is cut away using a razor cutter and scissors. What's left is the wooden stand and buck covered in the clear plastic. Then I created an ad hoc surface gauge using a craft razor and my anvil/vise in order to make an even score line on the plastic. All i needed to do was turn the buck against the razor and I got a level score on the clear plastic. Once scored, I could peel away the waste and then pop the dome off of the buck.

I'm pretty pleased with the dome shape, and so I made 2 more (one of which has a flaw and I used it for testing).

Off to Google! I needed to find a nice image of a cornea for the eye. I settled on a nice brown eye with a large pupil (but not too large). Then I used Photoshop to remove light reflections and to make a complete round image with a dark border. That was sized so that I could print it onto glossy photo paper to make a well proportioned eye.

Printed cornea positioned inside the clear dome

Eye veins painted on the inside of the dome

The sclera painted on the inside of the clear dome

I marked the position of the cornea onto the clear plastic and then painted some veins on the interior of the dome using the position line to limit the area. The veins will give eye a bloodshot look. Next came the tricky task of mixing up some clear polyester casting resin in order to fill the plastic dome up to the line, and then place the printed cornea onto the resin. After that dried, i painted the rest of the interior of the clear plastic dome with two colors of spray paint; a textured and speckled light brown and a solid off white. This defined the sclera of the eye.

While all of that was happening, i started to build the mechanical support for the eye. This time I decided to limit the eye movement to a side to side motion. That will make the eye movement much easier and more secure. Once again, I decided to use aluminium as the material for the structure because it's light, strong, and easy to work with. A solid ring around the eye will give a support to the movement axis and the blink pivots.

Unfortunately, I didn't get any close ups or interim shots of the bracket attached to the aluminum rings. As you can see in the above photo, I used aluminum U channel. On each end of the channel, I cut out about a half an inch of the middle, so that each side of the channel could be folded out. I drilled and tapped those "wings", and then drilled matching clearance holes on the ring. An additional strip of aluminum was cut to size with clearance holes. In the image above, you can see that screws slide through the aluminum ring, through the additional strip, and then screw into the U channel wings. All together in made a solid mount for the aluminum rings.

One end of eye pivot and the back half ring support

Back side of eye showing mechanical attachments

I placed an additional half ring on the back of the eye support rings to provide additional mounts and to strengthen the eye socket. The eye pivot shaft was cut from 8-32 threaded rod. Plastic washers provide spacing as well as a frictionless surface for the rotation. An aluminum tube was cut to size in order to provide internal support to the plastic eye. Also, a metal bracket was cut and folded to provide a lever arm (for the side to side pivot) to the back of the eyeball. Some elastic was mounted from the back of the eye socket to the sides of the eyeball support bracket. The elastic provides a return resistance to the left & right eye movement. Finally, a ball joint was added to the eyeball bracket so that a brass rod can connect both eyes, coordinating the side movement.

And here is a final shot of the pair of eyes mounted on the U channel and aluminum tube supports.

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Ithorian (Hammerhead)

And now we come to my current project, aiming to be debuted at the 2014 Comic-Con in San Diego. What's different about this one is that it's not based on a specific character, but instead it's a member of the species that only had about 2 seconds of screen time in the first Star Wars film. Most folks know them as the hammerhead looking guy in the cantina scene. Officially they are known as Ithorians, and there are a large number of characters from that species in the extended universe.

Star Wars: The Old Republic, head and torso shot

Star Wars: The Old Republic, hands and feet

They also appear from time to time in the game Star Wars: The Old Republic, and I captured screen shots of those characters whenever I came across them in the game.

My first step was to take a wooden artist's model and use Plasticine to create a scale reference. That let me experiment with proportions and shapes until I got a look that was a nice synthesis of the reference photos. From that I took a bunch of measurements and scaled them up to my size.

Making a pattern on muslin that fits to my body form

My next step was to make a foundation for the costume. Based on some videos I've seen, I decided to make an FX corset. This is a standard costuming trick used whenever a special effects prop needs to be attached to the performer's torso. I used my body form (which I've talked about in other blog entries) to create a form fitting pattern. I sewed it up and then adjusted it on the form as well. I ended up with a corset that fits solidly and securely. And the lacing on the side lets me adjust for any body shape changes.

Side/front view showing the overall support structure

Next came creating a structure on which I can build the body. The outer structure will be upholstery foam, and I'll need the structure to hold it up. It should hold the shape of the body's "hump" around my head, provide attachment points for mounting actuators and other controls, and let me counterbalance the eyes that will be cantilevered off the front of the structure. I used aluminum tubing to keep the weight down but still maintain strength. Also, most of my woodworking tools can work with aluminum, so my wood shop is now also a metal shop (actually, I already use the shop to do a fair amount of metal and foam work). The first picture shows how I use a Styrofoam head for sizing the supports, and also shows the pockets sewn onto the corset for holding the aluminum tubes. The second picture shows the full support structure along with the spring supporting the forward part of the head.

Chicken wire molded to shape the outer shell

Cover with aluminum foil and then duct tape

Complete duct tape layer, mark the pattern cuts

Aluminum foil/duct tape pieces laid flat and transferred to construction paper

Cut off the outer layer along pattern lines

To create the foam body, I needed to make a pattern. I used chicken wire to mold the shape I wanted over the support structure, using the clay mold as a guide. The wire was fairly easy to shape, being both light and flexible, and duct tape held pieces together as needed. Once the shape was good, I covered the whole thing in aluminum foil and then duct tape to hold the final shape. Next, I cut the foil and duct tape shell up into the pattern pieces for the foam and then transferred the shapes onto construction paper to be the final pattern.

The foam body built from the pattern. The head has an additional modification based on the eye components

The pattern was then transferred to 1" foam, the foam pieces were cut out, and then it was all glued together. I used Weldwood contact cement (made by DAP) on the foam. It's smelly to work with, but the final glue joint is very strong. I never got a picture of the original foam structure. The above picture was taken after modifications made for the eye mechanism.

I'm going to mention the details of my first attempt at then eyes, but I wasn't happy with them and so I'm now in the process of rebuilding that part of the head. a future post will deal with my current process, this is a catch up post.

The eye mechanism showing the painted eyeball, eyelid/blink mechanism, and support structure

Back of the eye mechanism showing the pivot support shaft and the control line attachments

With the eyeball and outer structure removed, the blink mechanism and brass tubing guides are visible

Back of the eye mechanism showing the brass routing tubes and the control wire manifold

I decided to use 4 inch Styrofoam balls for the eyeballs. They're light and the right size. I found some ball joints at a remote control hobby shop (used in remote control planes) and I placed them in the middle of the balls by drilling an access hole in the back. I drilled and tapped an aluminum post in order to hold the ball joint and the eyeball while allowing rotation in all 3 axes (roll pitch, yaw). I them built a structure around the eye that holds the ball, and provides mounting points for other controls. Some 18 gauge wire was formed into eyelid actuators, and I planned on mounting foam to the wire for the eyelid skin. The metal structure also had brass tubing attached in order to route the control lines. The tubing was bent with gentle curves, and the control lines (nylon fishing line) were attached to the eye and eyelid, providing eye motion and blink controls. Finally, some more wire was shaped in order to provide an outer protective structure and foam was again cut into shapes that would form that part of the head.

Finally I covered one of the balls in Spackle in order to smooth out the foam's pitted surface, and sanded it down until it was a smooth ball. Then I painted it, and the paint screwed up the surface leaving it with a bumpy texture.

Foam head structure wrapped around the eye mechanism

The eyes took weeks to make. Each design decision made sense at the time, and I would spend hours fitting parts together to make them work. And by the time it was all done, I hated the result. You can see how it looks in the picture above. The eyes are too big, I don't like the look of the eyeball, the shape of the head is wrong, there are too many degrees of freedom in the eye movement, and overall it just looks like a cartoon character.

So, I took a break to rethink the design. I also watched more tutorial videos looking for another approach. The vacuum forming class which I posted about was a part of this rethinking.

That's where I'll leave this catch-up entry and discuss my new efforts in a separate post.

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Ithorian: Head movement

Ithorian: New approach to the eyes

Ithorian (Hammerhead)

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