Hands - Redux

I decided to have another go at the hands for my model. I had planned to make gloves for my original hands but found that I lack the sewing skills to do so. This time around I decided to cast the hands in rubber over an animation wire frame. The rubber should be flexible enough to allow movement yet rigid enough to keep it's form.

I started by building a model of a hand out of clay.

I used a simple wire frame to start,

then built up the hand using the clay. Once the clay dried, I cleaned up the shape a bit with sand paper and smoothed out the surface.

The next step is to make a mold of the hand. I used Sculpey brand clay for the mold because it is a little flexible after it cures. This comes in handy when putting the two sides of the mold together. Also, Sculpey cures in about 15 minutes in the oven so you don't have to wait overnight for it to dry. I baked the bottom side of the mold first.

After the bottom side cooled, I put the model hand back into the finished mold and formed the top over it. You must be very careful not overlap the top side and the bottom side. You want them to be flush, but they need to come apart in the end.

I baked both the top, bottom and the hand together in the oven. This way I could be sure the top will hold it's shape while curing. After the mold cooled I pulled it apart, and set aside the model hand.

Next I needed to add a release agent to the mold so the rubber would not stick. I like vaseline because it does not pool at the bottom of the mold once applied. I covered every surface where the rubber would come in contact with the mold with vaseline. The next step was to build a wire armature. I used animation wire to form a hand shape that was slightly smaller than the mold. 

I used duct tape to secure the two sides of the mold.

The seam around the edge of the mold must be sealed. I wrapped the entire mold in tape, then used a clamp to set it upright. I did not put much pressure on the clamp because it was in danger of breaking the mold.

The rubber I used for the hands is called Poly PT Flex 60. It is a two part system, you mix 1 part a with 1 part b and pour into your mold. Very simple.

Once set, the color of the Poly PT Flex 60 is kind of a transparent amber, which is not the color I wanted. I added pigment to part a of the mix to change the color to black. You can buy pigment for liquid rubber but it is kind of expensive so I used oil paint. There are a number of dyes you can use to change the color of the rubber as long as they don't contain any water. The chemicals in the liquid rubber convert the water into carbon dioxide creating thousands of tiny bubbles, which will ruin your day. The rubber turns into a very slow, but unstoppable, volcano.

After adding part b, I mixed the two parts thoroughly, and poured the mix into the mold. I used an alligator clip to suspend the animation wire in the rubber mixture.

I let the rubber cure for about an hour before removing the tape and slowly pulling apart the mold. 

One freaky alien hand done, one to go.

Simple Green Screen Butterfly

I made this animated butterfly for an upcoming project. I decided to build a larger model than what would appear on screen, shoot it in front of a green screen, and shrink it down in post. I thought this process would be easier than building a tiny model and trying to animate it on set. Also, this model needed to be suspended in mid air with wires and removing wires on a green screen is relatively easy to do. Although the process looks somewhat difficult, with the right software it is actually very simple.

I started with my model suspended on a wire. I have already removed the wire so it is not visible in this example. I animated the butterfly and brought the completed frames into After Effects.

In After Effects, I shrunk the butterfly down to about 5% percent of it's original size. I then animated the flight path simply by changing the butterflies position and adding keyframes along the timeline. You can change the curve of the path by dragging the bezier handles at the beginning and end of the path.

I removed the green screen with the Keylight 1.2 effect in After Effects. It is one of the easiest plugins to use. All you need to do is choose the color you would like to remove by selecting the eye dropper next to the "Screen Colour" swatch and choose the color you would like to remove from within your animation. There are several adjustment tools to play with to get the exact look you want.

I then added the background and changed the color from purple to yellow using the Photo Filter effect. I also adding a glow to enhance the light reflecting off of the wings.

Here is a video of the different stages of development.

Wooden Armature - Part 4 - Hands

Hands. I started by bending animation wire into shape.  I thought his hands would be too wide with four fingers, so I am only making three fingers and a thumb for this model.

I twisted the wire to form the fingers and the wrist.

You have to be very careful not to leave tool marks on the fingers. They are very susceptible to breakage being that they are so small.

I added epoxy putty to the palm of the hand to make the whole more solid. At this point it is import that you remember that you are making a left a right hands so you can position the fingers correctly.

I added common self adhesive bandages to flesh out the fingers. I will making gloves to put on the hands so the fingers will be covered in the end. 

I then used my dremel to sand down the dry epoxy putty to a more pleasing shape. You must be very carful not to hit the animation wire or you will need to start over.

Then I wrapped the wrist in heat shrink and attached it to the arm using more epoxy putty.

Now he's starting to look like something.

Up next... Clothes.

Wooden Armature - Part 3 - Feet

Feet. I started by cutting out a basic foot shape from two 1x6x13 of pine glued together. It only took a couple of minutes with my new used scroll saw. I then separated the pieces so I would have two shoes the exact same size.

I drilled a hole on top to stick the animation wire in. I then used a dremel to round of the sides and sanded the shoes smooth with a detail sander.

Then I painted the shoes black.

Next, I drilled a hole in the bottom for a nut. The nut will be used to hold the model in position when animating.

To attach the nut to the bottom of the shoe, I first screwed the nut onto a threaded rod.

Then I filled the holes with epoxy putty and pushed the nut into the bottom of the shoe. I then unscrewed the threaded rod and removed the excess putty.

To attach the shoe to the armature, I started by twisting together five pieces of animation wire. I used epoxy putty to secure the animation wire to the legs of the armature.

I cut the wire down to size and covered the exposed portion with heat shrink.

Finally I filled the holes on the top of the shoes with epoxy putty and attached them to the bottom of the armature.

Up next... Hands.

Wooden Armature - Part 2 - Arms and Legs

Arms and Legs. For the arms and legs the first thing I did was cheat. I was going to carve the arms and legs out pine just like the head and the torso but then I thought "Don't they make round pieces of wood and sell them at a reasonable price at the hardware store?". Turns out you can buy wooden dowels just about anywhere for pretty cheap. I got some poplar dowels of various sizes for about a dollar a piece.

I cut the dowels to size and drilled holes in the ends. I drilled the holes first because I am going to round the ends and it is extremely difficult to drill holes on a rounded surface.

I used my dremel to shape and round the ends of the dowels. They will be covered in clothing in the end so was not to concerned about the appearance.

To attach the arms to the torso, I started by first twisting the animation wire together,

then filling the holes with epoxy putty,

and finally pushing the wire into the putty. The epoxy putty is only workable for a couple on minutes after you mix the two compounds together. After the putty becomes hard it is extremely hard to work with and can damage your model.

For the legs, I twisted together 5 pieces of animation wire. This will make the joints in the legs strong enough to hold up the rest of the body. As I was finishing up the last limb I realized that I had forgotten to cover the exposed wire. It is good practice to cover any exposed animation wire as it can break more easily if it is damaged. The best way I have found to do this is to use heat shrink. You can buy heat shrink in the electrical section at any hardware store. Unfortunately, I cannot put any on now that the model is together, so I am just going to use electrical tape. Since the model will be clothed I don't think it will be a big problem.

Up next... Hands and Feet.

Wooden Armature - Part 1 - The Torso

The Torso. I started off the with the same 1"x6"x13" pieces of pine I used for the head. I only needed three pieces glued together this time. I got a new used scroll saw from a coworker so I decided I might as well try it out. The wood was probably a little too tall for the this type of saw but I took it slow and It worked pretty well.

Next I used the a chisel to round out the sides of the block. Unfortunately I cut the block upside down so instead of chiseling top to bottom I had to chisel bottom to top. Although it's wasn't the end of the world, it was annoying.

It kind of looks like a giant thumb.

I used my smaller chisels to carve out the basic shape for the torso. I made a couple more cuts with the scroll saw to give the shoulders a little more definition.

Then I took my dremel to it. By the way, you should never chisel after you start sanding. The little bits of wood from the sanding process can get in the way of your chisel and cause all sorts of problems. I ended up taking quite a bit off as you can see. I think my original idea of the torso changed as worked with the wood. 

I then sanded down the rough edges with a detail sander.

I drilled holes for the limbs and neck in the torso. The hole for the neck is about 1" deep and the holes for the arms and legs are about 1/2" deep.

To attach to head to the torso, I used pieces of animation wire twisted together.

You must be careful not to leave tool marks on the wire. Tool marks creates weak points and can lead to breakage.

I used epoxy putty to attach to wire to the torso. This stuff works great and smells terrible. I kneaded the two compounds together for a minute or so before putting it into the holes I drilled earlier. I then stuck the animation wire into the hole. After about an hour the epoxy putty is dry enough to test the joints.

I attached the head in the same way. Now he's a real boy.

Up next... Various appendages.