使用js获取3d模型的尺寸（尺寸）

I actually work on AR project with three.js and i handle some 3d models, but I have some problem with the sizes of the models. Because I want them to all have the same size, so I needed to set the same dimensions to all models. I first tried to solve this by using boundingbox and boundingsphere but it doesn't work.I actually work on AR project with three.js and