IK = Inverse kinematics, FK = forward kinematics
Let's take an arm animation for example, from shoulder to fingers, like making a "salute" kind of animation.
FK: as the name suggests you'd have to first animate the shoulder joint, then elbow, then wrist... all manually.
IK: You'll move the hand to the end position and IK calc's backwards where the other joints up to the shoulder should be (how good this looks depends your joint settings etc).
So basically IK is easier for the animator, but needs careful joint tweaking and some math from the animating program. And how this is all is related to Blitz3D? It isn't. Blitz3D doesn't care how the animation was made originally, it just plays the animation data (keyframes), doesn't do any IK/FK calc's as such (it DOES keyframe "tweening" from one keyframe to another though).
Let's take an arm animation for example, from shoulder to fingers, like making a "salute" kind of animation.
FK: as the name suggests you'd have to first animate the shoulder joint, then elbow, then wrist... all manually.
IK: You'll move the hand to the end position and IK calc's backwards where the other joints up to the shoulder should be (how good this looks depends your joint settings etc).
So basically IK is easier for the animator, but needs careful joint tweaking and some math from the animating program. And how this is all is related to Blitz3D? It isn't. Blitz3D doesn't care how the animation was made originally, it just plays the animation data (keyframes), doesn't do any IK/FK calc's as such (it DOES keyframe "tweening" from one keyframe to another though).