Some info for Richard

(Hos) #1

I received an e-mail recently from a blender
user who wanted to know a bit more about
constraints, so I thought I would answer it
here so that others might benefit from my
sagely wisdom. :wink:


Here is the #1 thing you must know to use IK constraints
effectively: The IK constraint affects the root of the bone,
not the tip of the bone. So when I constrain the null
bone to the grabber bone, I am saying “Make the
root of the null bone point at the grabber”. Now,
due to the fact that the root of the null bone is
connected at the same place as the tip of the
lower leg bone, the net effect is that the tip
of the lower leg bone points at the foot grabber
bone. This might seem weird at first, but it is
quite flexible and allows for more complicated
constraints such as the knee controller (and
now you know why that constraint is on the
lower leg – it makes knee which is at the root
of the bone point at the knee controller).

Take a look at these links, in particular the first one
which is the official NaN docs about armatures and

No prob