osg::ref_ptr<osg::BlendFunc> pBlendFunc = new osg::BlendFunc();
pBlendFunc->setSource(osg::BlendFunc::SRC_ALPHA);
pBlendFunc->setDestination(osg::BlendFunc::ONE_MINUS_SRC_ALPHA);
geode->getOrCreateStateSet()->setAttributeAndModes(pBlendFunc);
geode->getOrCreateStateSet()->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);