The Pendulum

This particular section of this book brings up an age old debate in terms of cg animation.

To animate fk or to animate ik. Ik is slowly starting to reign supreme(in my opinion anyways) but it brings up some unique problems. Particularly arcs. Obviously the upper left example of the image is the correct one. While the upper right image is completely wrong.

Yet this is what we will get when animating ik, is the image on the upper right. Yet ik seems to be how most of are animating lately. Why do we get this when animating in ik? Well ik deals only in terms of translations. So the computer plots out the fastest way to get from a to b, and we get this straight path of action, with no arc whatsoever. The movement is completely unnatural. If we were to animate in fk, we wouldnt have to worry so much about our arcs, as the computer would rotate from a particular pivot point and the arcs would create the obviously more natural movement. So i'm going to create the pendulum and animate on in ik, and one in fk with just a basic sphere. So I went and animated the resulting pendulum based on the diagram given, in fk.

So its going pretty good. Im not a fan of the timing, but its the diagram given :S

Now I've done one the exact same timing in ik and heres what we get.

Well,its not really working is it. I guess I have to go in and work some more. I only need to animate the one axis in fk, but in Ik I need to go in there and do some more work. Guess I better go do it.

Same result, just more work.