Tuesday, May 26, 2009

Have a Seat, part one

Have you ever built an armchair on a miniature scale? How about one that is designed for animation - that is, it is very sturdy yet very light? Well for Part One of this post, I will show you how I designed the frame of the chair to be extremely light yet sturdy enough to bolt a character to it. I will also show how I made the back stuffing. Part Two will cover the rest of the upholstering (coming soon).

If I've said it once, I've said it a thousand times: to animate smoothly you must have total control of your character. In other words, you need to have him bolted securely to your set whether he is standing, sitting, jumping, or even flying. You simply cannot have the character "accidentally" falling over or bending, even slightly, in a direction you didn't intend due to gravity. These minor things end up looking huge when you play your animation back and makes the character's movements jerky and not like natural life.

This poses an interesting dilemma for designing set pieces the character interacts with, like chairs. Our main character, Chris, does a lot of sitting (exciting guy, right?). This means that the chair is going to have to be designed in such a way that he can be bolted through the seat of the chair to make sure he doesn't move unless I want him to. At the same time, however, if the chair is going to "jump" in the air, it needs to be light enough to be held by one of our flying rigs. Light and sturdy is the name of the game!

This is, for all intents and purposes, the entire functional structure of the chair. That's everything! Four very sturdy legs and a tabletop made out of basswood. The legs will be bolted to the set and the character will be bolted to the top of the "table".

..... that was actually pretty easy to figure out. Now the hard part: the rest of the chair. I am going to use balsa wood as much as possible to keep it light. Notice the sides of balsa wood in the above picture.

To simulate "thick" arms, I am using two light pieces of balsa wood with a square wooden rod glued between them. I could use just the balsa wood (no wooden rods between them), but balsa wood is really fragile and as soon as I grab the arms to move it they would break and ruin it all. Here's another view:

Looking at the above photos, you will notice another rule of animation: cut any corners you can. Now I don't mean to be sloppy - I mean that if people aren't going to see it, don't sweat it! I was using wood glue on these pieces with reckless abandon..... but only because no one is ever going to see inside the chair :)

Just like the arms, I know the back of the chair is going to be under a lot of stress when people grab it and move it around. That's why I used a big piece of basswood for the back instead of balsa wood. A little heavier, but necessary for this part. I also put on the front panel (balsa wood):

The back looks a little thin, right? I am going to use the same technique I used with the arms to make it thicker, but this time it's different. The back needs to be rounded, that is, a bit convex to give it more realistic detail. To accomplish this look, I will make supports along the middle that are three rods thick and supports along the sides that are two rods thick. The balsa wood is flexible enough to bend around these supports. Lost? Check out the pic below:

Make sense yet? Look down on it from above:

See how they round off from the center to the sides? Perfect for bending the balsa wood around. I had to hand-sand these wooden pieces so they would be rounded to fit the balsa wood I am about to bend over them.

Here I am gluing the pieces to the back. Clay makes a great weight :)

The back is wider than a single slat of balsa wood so I need to glue two slats together. Here's a little tip for those of you who do not glue wood together very often: if you are gluing the end of a piece of wood to something (like the ends of these slats of balsa wood), the glue does not hold as strong. To get around this, spread a little glue on each end and let it dry ahead of time. That way when you glue the two pieces together, there is a little something for the glue to grab on to.That's what's happening in this picture:

Unfortunately, when I attempted to bend the (now glued together) piece of balsa wood around the supports, it cracked right next to the seam! The glue held perfectly, but the piece was breaking!! So out of one part frustration, two parts improvisation, I just duct-taped the pieces together. Viola.

After the back was attached - and essentially "thickened" - it was time for the upholstering. First, I marked out where each cushion will be. Then I used my handy-dandy spray glue to attach some un-rolled cotton balls to the fabric.

A small bead of hot glue along each line attaches the fabric to the chair. This fabric is green vinyl that looks just like leather under the camera. I bought a huge sheet of it from Joann's, a fabric store, for only $6!

After trimming the excess off the sides....

And adding the trim to the sides...

That's all for now! Next, we will add some styrofoam to the arms to give them a nice rounded look, and after that we simply wrap the vinyl all around the entire frame. It will look like a nice thick, heavy chair, but only you and I will know that it is actually light and hollow!



  1. That's awsome! Really nice work :D


  2. great post....watchin and learnin.


  3. Thanks Marnik and Shel/Justin!

    Hey anyone out there who likes following our blog, make sure you check out the blogs of these two also. Great stuff and generous with the info, the both of them!