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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?

enter image description here

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  • $\begingroup$ I somewhat understand your problem statement. I think a carefully chosen few Blender Screen shots would make your situation clearer. A suggestion is to search IK (inverse kinematics) and the related FK (forward kinematics) for armatures and see if this help you to express your situation. A suggestion is to always place an image in the problem statement. After you determine your images, a suggestion is to rewrite your problem statement. State what is required and prohibited. $\endgroup$ – atomicbezierslinger Mar 5 '16 at 20:24
  • $\begingroup$ IK helps some bones to stay in a designated location while other bones move in a controlled fashion. 30 minutes of exploring that will help. $\endgroup$ – atomicbezierslinger Mar 5 '16 at 20:26
  • $\begingroup$ I've just added the picture for the pickaxe-scene. $\endgroup$ – Eti2d1 Mar 5 '16 at 20:48
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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.

sample animation

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.

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