[Bf-committers] blender2.5's new IK

Benoit Bolsee benoit.bolsee at online.be
Thu Sep 17 17:44:51 CEST 2009


Since the last Emails on this subject I added a couple of features that
should be useful to animators.

First I implemented an 'animation' mode where the solver operates like
the old one: the solver is stateless and uses the pose from Fcurves
interpolation as the start pose before the IK convergence. Still the new
solver is significantly faster (4x) and provides features that are
inherant to iTaSC: multiple targets per bone and multiple types of
constraints (currently only CopyPose and Distance).

The second feature is a joint rotation constraint that allows to control
the bone rotation while the IK solver is tracking the targets. If both
cannot be achieved at the same time, the solver will do a balance
between the constraints based on their relative weights. Many
applications can be derived from this concept:
- manual tuning of IK pose by rotating bones in the UI
- give preferred direction for certain bones (relative to parent bone)
- automatic deviation from precorded actions based on a cartesian
constraint (e.g. avoid an obstacle)
- smoothing of a precorded action based on robot dynamics (e.g. max
- control the joint angle by python

A test build with documentation is available on Graphicall if you want
to give it a try.  


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