Blender Motion Kit : User Guide

by Jean-Baptiste PERIN


Blender Motion Kit is a set a scripts that allows to export IK-based animation to bvh file format

Blender Motion Kit was introduced in Blender 2.40 RC1, because in this version, IK solver wasn't providing access to armature's data while IK Solver was working. In 2.40,
It allows to use animation produced by IKSolver into Blender game engine through the use of body parts controlled by ipo.

KIT CONTENT
HOW_TO_INSTALL_THIS_KIT_
HOW_TO_USE_THIS_KIT
WHAT_ARE_THE_LIMITATION_OF_THIS_SCRIPT
ANYTHING_ELSE

KIT CONTENT


Blender Motion Kit contains the following scripts:
Blender Motion Kit relies on the principle that, even though we can't read motion information from bones (in 2.40 RC1),  we can still attach empties to bones, and then get bones rotation and position information from these empties. Thus .. a typical IK Baker session is divided into 3 steps:
  1. After creating the armature you want to animate .. create empty for each bone of your armature and attach them to the bone. This step is eased by the use of Arm2Empty.py script
  2. After animating your armature ... export it to bvh format thank to IKBaker.py script
  3. once your animation is exported into a bvh file ..you can import it by using bvh_import.py script



HOW TO INSTALL THIS KIT ?

Copy IKBaker.py, Arm2Empty.py and bvh_import2.py into the ".blender/scripts" directory of your Blender installation.
In a Script window, go to the "Script" menu and click on "Update Script" entry.


HOW TO USE THIS KIT ?

Here's a little tutorial showing the key step of an IK Baker session..
Armature Creation

You should get somehting like that : (for each bone of you armature .. an empty was created with the same name, location and rotation of the associated Bone)


Empties Creation

Constraints Creation

Note that the name of the bone to which the empty is constrained is the same as the empty's name

At this point I recommand that you save your work (Ctrl-S) .. it was fastidious not to risk a complete lose..wasn't it ?
We are now ready to animate our armature ..

IK SolverCreation

In our example .. we use a 3 bones long IK chain  ..

IK Chain Testing

At this point, you can test your IK chain by grabing the empty created in the previous step .. you should see bone and their attached empties moving while you're grabing the target Empty.

We now have an armature that we can animate through the IKSolver. Let's see how to make the animation.





You now have a .bvh file representing your animation .. to load it .. follow the steps below


WHAT ARE THE LIMITATION OF THIS SCRIPT ?

Armature must be made so that each bone's head corresponds to  its parent bone's tail ..  there can't be some hole in the chain.
If your Blender file contains several aramatures .. there must not be any common name between these armature.

HOW TO USE THE DEMO FILE ?

Watch the animation (Alt-A) and/or change it by animating the empty named Empty

Run IKBaker.py script

It creates a .bvh file

In an other Blender session .. import the bvh file by using the bvh_import2.py

ANYTHING ELSE ?

Blender Motion Kit is released under GPL licence
read the LICENCE file or visit:
http://www.gnu.org/copyleft/gpl.html

Futur releases will be made available on:
http://perso.wanadoo.fr/jb.perin/

Bug report, evolution requirements, remarks and comments can be posted here:
http://www.zoo-logique.org/3D.Blender/newsportal/post.php?newsgroups=3D.Blender&type=new
Put [ Blender Motion Kit] in front of the "Sujet:" field


visitors since creation on december the 20th of 2005.
visitors since creation on december the 20th of 2005.
(C) 2005 Jean-Baptiste PERIN - released under Blender Artistic License - www.blender.org