In 2.49, you could adjust the maximum length of Auto-IK Chains by using scrollwheel up/down or page up/down while moving Auto-IK bones. Now this is possible again with those hotkeys, but you need to hold SHIFT to get this to work, otherwise we get a conflict with the hotkeys for proportional edit nowadays.
Was broken when transform tools switched from using hardcoded key mappings to using a modal keymap.
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Solving is now done independent of scale, by scaling the chain to have a
size of about 1.0. This solves some issues with small or big chains, and
also makes the IK stretch setting independent of scale. The latter breaks
backwards compatibility somewhat, but is an improvement over what it did
before.
module -- the previous method could be off pretty far.
- Added drawing of transparent surface for it, instead of just the border.
- Added "stretch IK", allowing bones not only to rotate, but also scale.
The "Stretch" value below the DoF buttons is used to enabled this.
- Some code tweaking: slightly simplified computation of transform for IK,
renamed chain to tree, removed unused pchan->ik_mat, ..
Internal IK module work:
- Do damping per DoF also based on stiffness, hopefully makes it converge
faster with very stiff joints.
- Instead of having two joints types (translational and rotational), now
all 6 DoF's can be enabled for one joint.
- Added limits for translational joints.
Fix some warnings.
Merge with latest soc code.
What changed in IK lib:
Fully restructured, with components now as follows:
- IK_Solver: C <=> C++ interface
- IK_QSegment: base class for bone/segment with 0
to 3 DOF
- IK_QTask: base class for a task (currently there's
a position and a rotation task)
- IK_QJacobian: the Jacobian matrix, with SVD
decomposition, damping, etc
- IK_QJacobianSolver: the iterative solver
The exponential map parametrization is no longer used,
instead we have now:
- 3DOF and 2DOF XZ segments: directly update matrix
with Rodrigues' formula
- Other: Euler angles (no worries about singularities
here)
Computation of the Jacobian inverse has also changed:
- The SVD algorithm is now based on LAPACK code,
instead of NR, to avoid some problems with rounding
errors.
- When the problem is underconstrained (as is the case
most of the time), the SVD is computed for the transpose
of the Jacobian (faster).
- A new damping algorithm called the Selectively Damped
Least Squares is used, result in faster and more
stable convergence.
- Stiffness is implemented as if a weighted psuedo-inverse
was used.
Tree structure support.
Rotation limits:
- 3DOF and 2DOF XZ segments limits are based on a swing
(direct axis-angle over XZ) and twist/roll (rotation
over Y) decomposition. The swing region is an ellipse
on a sphere.
- Rotation limits are implemented using an inner clamping
loop: as long as there is a violation, a violating DOF
is clamped and removed from the Jacobian, and the solution
is recomputed.
Convergence checking is based now on the max norm of angle
change, or the maximum number of iterations.
