Help with getting bounding box

I have created the bounding box attachment on root bone and I am doing this :

SkeletonAnimation *playRod;
playRod = SkeletonAnimation::createWithFile("home_page_animations.json","home_page_animations.atlas",1);

And when I print the playRod->boundingBox().size.width and playRod->boundingBox().size.height , I get zero as width and height.

What am I doing wrong ?

bump

spine-cocos2dx for v2? What happens in SkeletonRenderer::boundingBox? Probably you haven't called updateWorldTransform.