I think I’m going to have the Birthday Card done by the end of the month, which turns out to be the end of the week. I was a little slow getting started on the robot hands this week but once I finally got focused, it went pretty quick. Mostly. I’m not quite done with the hands but close enough that I can see the end of this project. And I learned something.
I got to thinking about the material I had selected for the hands. I started thinking that they would really overwhelm the look of the balloons. And someone might think they looked a bit like C-3PO. I didn’t want that. So I spent a bit of time finding a better
material combination. I ended up with a stainless steel and titanium combination. It works for me. I really like the subtle difference between the two materials. It helps to add a little definition to the different parts.
I had to go back and re-watch part of the rigging tutorial. Just for the hands. Oh, and I think last week I said it used 3 fingers and a thumb. I was wrong, it uses 2 fingers and a thumb. So, I had much more work to do to set up the bones for each hand as 
compared to the tutorial. Fortunately I didn’t have to follow along step by step this time. I left off any arm or wrist bones since I really don’t need that functionality for this. I did add a global control so that I could link everything back to it to make moving and scaling things easier. I tested that just with the bones. I’ll want to test that again once everything is skinned.
When I set up the controls I did add a wrist control for each hand, even though I didn’t add a wrist bone. I figured it would make it easier to use that to rotate a hand up or over or whatever instead of trying to do it from the hand bone.
As you can see there are a fair number of controls for the fingers. The most challenging part with this setup is remembering what to link to what. Because it uses a double joint 
system, which I think works really nicely for what I’m doing, the controls don’t link just to the one bone they are aligned to. The orientation constraint links from the bone to the control. Then there is some position constraint linking to the bone or control above it. Then to control the trailing bones wire parameters are used to get that added bend. It will take some time before that becomes second nature to me. Here’s a look at the hierarchy of the left hand bones and controls.
Ok. So I did procrastinate a lot when it came to starting the rig. Even though creating the bones turned out to be really fast and easy. Then I delayed again with setting up the controls. It’s really silly that I did that because once I got going, it went pretty quick too. At that point I was pretty well into getting this done so I reviewed the skinning step. I wasn’t entirely sure it was as easy as I thought it was. Sure enough, it was. However, I had one little question. When I did Sticks, he was all one piece so I just followed along with the tutorial. In this case I have two separate objects, the left hand and the right hand. So I had to figure out if I was going to be able to do each as it’s own entity. Turns out, it is sort of covered in the tutorial. That has the eyebrows as separate entities so they are skinned separate from the rest of the character though their rig is connected to the global control. I didn’t remember this because Sticks has no facial features so I didn’t pay attention to that the first time through.
Since I was going to skin each hand as a separate entity and they both have so many bones, I got clever and set up two selection sets, one for the bones for each hand. This was really easy since, as you can see in the picture of the hierarchy, I used a good naming convention. So I searched on “Bn_L” and was able to select all the left hand bones. Then I added them to a selection set for the left hand. For the right hand I searched on “Bn_R” and was able to create a selection set for the right hand. This made things a lot easier for skinning. I applied the skin modifier and when I went to add the bones I pulled up the
appropriate selection set and clicked the select button and I was all set.
The last step in the rigging for the hands is setting up the bone weights. This is the most fiddly part. I did like the tutorial shows, and setup a pose using key frames so I had an animation that I could scrub through. Once I got the hang of what I wanted to do, and saw that it worked, it was fairly easy to get the weighting for the fingers, and part of the thumb. Unfortunately the hand and the first thumb joint weren’t so easy. These were the particularly fiddly bits. I spent the most time on these parts.
So far I’ve got the right hand rigged and skinned but not weighted. I have the left hand rigged, skinned and weighted. I even rendered a couple of frames so you can have a look.
And here’s where I learned something. I discovered that I don’t really have the angle of the thumb quite right. I don’t have the base model at the correct angle and as a result, I didn’t get the bones at quite the right angle. It means my controls are a little off so the thumb doesn’t behave quite as you would expect. Fortunately, it’s not a big problem and I can still work with it as it is. However, it is something I will want to remember for future rigs.
What’s left is to set the weights on the right hand and then get both hands into the Birthday Card scene and pose them. I think I can have all of that done and a final render completed by the end of the week. I’m on vacation from the day job this week so that
helps. And I don’t have a lot of things planned to get done so I don’t have much in the way of excuses at this point. Look for an announcement when I post it on the store. And then check back next week to find out what’s next.