How to get the boundingSphere of a model in primitives

I used (scene.primitives.add) to add a model, the loading format is gltf, I want to get the boundingSphere coordinates of the loaded model, but I found that the value obtained directly through the object property is undefined, I want to ask how to get the boundingSphere and its center coordinates, you can browse his boundingSphere center coordinates in the console, but direct printing will only get undefined, help!