Tuesday, March 26, 2013

Bone Rigging

If you already know this, please forgive me. 

In animation the way you get the illusion of movement is by drawing a picture then drawing a second picture that is slightly different from the first, then a third and a fourth and so on.  When those pictures are shown to the human eye at approximately 24 pictures a second our brain is convinced the objects on that page are moving.  That means a 7 minute cartoon will have approximately 10,080 individual pictures.

From the very beginning animators have been trying to find ways to reduce the number of drawings needed.  The greatest invention for animation was the frosted cel; a transparent  piece of paper that could be drawn on so that backgrounds need only be drawn once and the images on the cels could be laid over the background to produce the impression of one picture.

I think it is safe to say without the cel animation would never have caught on as a commercially viable form of entertainment.  But even with the cel you still have to draw each movement you want your objects to make.

In computer animation your object is made of points (or vertices depending on the program).  The computer program calculates where the lines will go in between the two points and what colors or textures to fill the shapes with.  To create the illusion of movement you simply tell the computer where the points will go from one second to the next and the program calculates the line movement.

But even that is too much effort for the lazy masses, so the animation geniuses have created another short cut; Bone Rigging.  Basically a bone in computer animation works like a bone in your body.  You assign all the points in your object that correspond to the bone and wherever the bone moves, so do those points.  So if I have 30 points in my head I can assign them all to a bone and I won't have to move every single point.

The picture above shows you the bone rig for my South Park Soft Ninja.  It is exceedingly simple.  In fact, I believe I will need a few more bones before I am done.  But for the animation I showed yesterday, that is all I used.

For the following animation I had to use quite a few more bones.

The animation above is the Soft Ninja doing a front kick.  I did this pretty quickly and it shows, but I'm learning as I go. I hid his arms and his eyes for my own ease.

Sadly, this whole bone rig for the Soft Ninja will likely need to be redone.  I have learned things since I did him and it might be easier for me just to start over than to try and work the new things into the old design.


  1. Omg!!! Wow!!! I knew about manual drawings of hundreds of frames for a cartoon but I never thought such great effort went into computer animation. Thank you for sharing.

  2. Thank you for stopping by.

    The real concerted effort of building a computer animation character is on the front end. If you've done everything correctly it will save you time in the long run. But, yes, there is still a huge amount of work to do.