[BoneAnimation] How solveIK method works?

Hello there,

I want my bones follow a generated spline. I thought the solveIK can be the solution, but the result is a bit strange.

Then I got an error when I apply solveIK to the first bone because it does not have any parent.

[bones-solveik.zip](https://github.com/armory3d/armory/files/2619749/bones-solveik.zip)

Any idea?

Reproduce the attached bones-solveik.zip case and inspect the solveIK call applied to the first bone, including the missing-parent error. Determine the expected behavior for a root bone and for following a generated spline; done means the behavior is understood and the issue has a confirmed fix or documented limitation.

Written by the indexing model from the issue text.