[dagmx]

It means that you can lock the end point to a position and figure out the rest of the pose.

Imagine a character walking with forward kinematics. Every time you move the characters hips , you’d have to rotate the leg joints and make sure the foot doesn’t slide. Remember virtual characters don’t have friction.

IK lets you lock the foot in a spot so you can animate the body above it without having to spend time matching the foot position.

In a real world, this is like if you tried to put your hand on a door handle while jumping up and down. It’s easier to keep position when you hold the handle than if you were to just touch it.

[wang_li]

It also means you can move the point and the rest of the joints adjust. Want to make your model walk? Just figure out the foot motion and the rest of the details are calculated based on joint range of motion and limb length.

[dagmx]

Without some extra solving most full body IK systems won’t give you walking motion. It’ll just be like pulling a doll by its limb or QWOP

You need a proper motion controller on top to actually have realistic walking motion driven by steps.