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458 Chapter 12: Animation
To specify a spline after the spline IK s olver is applied:
You can also apply a Spline IK solver to an existing
bone st ructure without select ing a spline, then
choose the spline later.
1. Create a bone structure w ithout an IK chain.
2. Selecttheboneorobjectwhereyouwanttothe
solver to start.
3. Choose Animation menu > IK Solvers > Spline
IK Solver. In the viewpor t, move the cursor to
theboneorobjectwhereyouwantthechainto
end and click that bone. Then right-click in the
viewport to end the IK solver creation without
choosing a spline.
4. CreateasplineorNURBScurvetobeusedwith
theSplineIKsystem.Itisrecommendedthat
you apply the
Spline IK Control modifier (page
1–820)
to it to place helpers at each vertex and
makethesplineeasiertocontrol.
5. Select the IK chain cross hairs and access the
Mo tion panel. In the Spline IK Solver rollout,
click Pick Shape and click the spline.
With this method, the position constraint is not
automatically assigned to the root bone, so it
must be assigned manually.
6. Select the root bone. Choose Animation menu
> Constraints > Position Constraint, and click
the helper at the end of the spline that you want
the root b one to follow.
On the Motion panel’s Position Constraint
rollout you wil l see the constraint assignment
to the helper/vertex.
To make the bones follow a path:
1.
Follow steps 1–5 in the previous procedure.
2. Select the root bone. Choose Animation menu
> Constraints > Path Constraint, and click the
spline.
3. With the root bone selected, go to the Motion
panel. On the Path Par ameters rollout, animate
the % Along Path parameter to ma ke the bones
move along the spline path.
Work ing with the Spline IK Solver
To use t he Spline IK Solver, move the helpers to
shape the spline. Do not move the spline. The
shape of the spline is determined by the positions
ofthevertices,somovingthesplineitselfhasno