private void blendSubtree(PhysicsLink rootLink, KinematicSubmode submode,
            float blendInterval) {
        assert rootLink != null;
        assert submode != null;
        assert blendInterval >= 0f : blendInterval;

        blendDescendants(rootLink, submode, blendInterval);

        if (rootLink == getTorsoLink()) {
            getTorsoLink().blendToKinematicMode(submode, blendInterval, null);
        } else if (rootLink instanceof BoneLink) {
            BoneLink boneLink = (BoneLink) rootLink;
            boneLink.blendToKinematicMode(submode, blendInterval);
        }
    }
Begin blending the specified link and all its descendants to the
specified kinematic submode.

@param rootLink the root of the subtree to blend (not null)
@param submode the desired submode (not null)
@param blendInterval the duration of the blend interval (in seconds,
&ge;0)
jme3-jbullet/src/main/java/com/jme3/bullet/animation/DynamicAnimControl.java