I wasn’t happy with how Billy was looking once the fur was on and decided the only solution was to re-build the head. This did give the opportunity to redesign a few things that weren’t working quite right in version 1.
The first thing I wanted to make sure was right from the start this time was the proportion of Billy’s eyes, nose and mouth. So started again with sketches before design started in CAD. 123d Design no longer exists, so i’ve moved on to fusion360, which is a lot more capable! I also tried to be a bit more organised in my CAD this time.
By the point of building this second head I’d also had a lot more 3d printing experience, so was able to produce much more accurate and a lot stronger prints.
One challenge of the new design was that there was a lot less besides the eyeballs to fit the mechanism for the eye lids. I tried a few ideas here with 3d prints but in the end compromised on having a steel loop with a 3p printed lid attached to it.
The other major change in this design is that I changed the lip mechanism, opting for a much simpler system of wires. The wire is guitar string that is soldered together. the guitar string has just the right amount of spring and bend and with some canny cable routing you can get it to behave as you want it to when the servo pulls or pushes. This system didn’t offer as much outward movement in the lips, making the “oooooo” sound harder to replicate. But by this point I realised that you can pretty much get away with just a couple of flapping gums and your brain will fill in the rest.
Going forward from this project I’ve started a new mouth design that I think will have many improvements and offer a much wider range of emotion from the mouth. Other issues with this design is that there was a couple of times in production where the solder joints broke. This meant I had to un-sew the lip and re-solder, then sew the lip back in place, a very fiddly job!
You may also be able to tell that I decided to start taking proper behind the scenes pictures by this point. I printed the new eyes with a bigger hemisphere that mkI this allowed billy to turn his eyes fully. They eyes, If I haven’t already talked about them, are on a small universal joint giving it free movement. I’m not entirely sure this was the greatest idea, a simple ball and socket would have probably worked better. But it was a fun exercise in making small 3d printed mechanisms.
You may also notice that there is no hinged nose mechanism. I ended up simply sticking this directly to the fur. It still moved naturally with the lips but was a lot easier to fit in the right place.
The detachable skull panels made maintenance a lot easier, at least that was the theory. I had to replace a couple of the servos, and this meant taking a lot of the head apart. It also meant cutting then re-sewing the fur in place. The main purpose of the skull panels though was to make sure Billy’s head had a good shape once the fur was on. I made a net similarly to how i did the first time, then glued it on to the eyelids. I sewed it onto the lip wire this time using a double threaded needle to create a thin and flexible black lip.
I wasn’t happy with the fur edge around the eyes on the first head. It has a thin binding sewn onto it that made his eyes look too dark. The solution on this head was to use a type of black adhesive sealant. I squeezed some into a small syringe and piped a small bead over the edge of the fur.
Once the fur was in place I was able to test the lip mechanism again. Below is a before and after fur comparison.
Hopefully rebuilding the head was worth it, I think it made Billy look a little more friendly at least and is a fair bit more robust than the first one. I’ll finish with a comparison pic of the two heads. If you’re still thinking this doesn’t look completely like Billy, I did get rid of the ears on this build, replacing them with larger ones that stick on the head with magnets. That was the last design change made on billy before animation began.
I’ve made a short edit of the whole head building process from sketching through to final head. Check it out below!