Locking vertices to rotate the object around them When I create an animation, it's always inconvenient to adjust certain vertices so they don't change their location during an animation e.g. if I want to make an animation about a person throwing an axe to a wall (see picture).

Of course, the bones of the upper- and lower-arm change their rotation since the whole body has to be stopped partly by the arm who's holding the axe. But if I change the rotation of one of these two bones the parented axe also changes its place e.g. it goes into the wall which shouldn't happen.

Therefore, I always have to adjust the bones to avoid this problem. And I have to do it for each frame the tip of the axe is on the wall.

Isn't there a solution to lock the vertices of the tip, so the whole axe doesn't go inside the wall (but can rotate around the locked vertices) even when it's parented to the arm which changes its rotation?
When you use forward kinematics, moving the body will move the arm and hand to follow the body motion. 

When you use inverse kinematics (IK) the hand can be positioned and will stay stationary while moving the body. Note that a hand using IK will normally pull away from the location if the length of the arm doesn't reach the location desired.

By animating only clive's body you can see that the hand using IK stays still while the hand using FK moves with the body.



If you enable the rigify addon, you can add a meta rig and generate the final rig to get an armature that has IK/FK controls that you can look at. There are also many rigging tutorials that cover IK controls.