Howto:Animate gear scissors using the tracking animation: Difference between revisions

Howto:Animate gear scissors using the tracking animation (view source)

1,003 bytes added , 8 May 2013

http://www.mail-archive.com/flightgear-devel@lists.sourceforge.net/msg40042.html

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 The new (in 2.11) '''locked-track animation''' can do exactly the same thing as the [http://wiki.blender.org/index.php/Doc:2.6/Manual/Constraints/Tracking/Locked_Track Locked Track constraint] available in Blender. However it can also be used to simulate simple inverse kinematic systems consisting of two bones connected with a revolute joint (aka hinge).
+If you get used to Blender its a really powerful tool (I have problems if trying to work with other modelling programs :P) and with using the
+right scripts it gets a very neat tool for creating models for FlightGear. For example for a gear scissor just add an armature with two bones, add an IK constraint to the second bone and attach an element of the scissor to each bone, and you are done. You can watch the animation in Blender and using an exporter script now it is possible to watch exactly the same animation inside FlightGear. You don't need to guess any coordinates/axes/etc. and if you modify and object you just have to export it again, without manually modifying the animation xml.
+There are (currently) only two axes required. The lock-axis and the track-axis. They should be orthogonal, as the rotation is only possible round the lock-axis. Internally the track-axis is always orthonormalized to the lock-axis, as calculations always are performed in the plane normal to the lock-axis.
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