Apply transformation to a 2dgs model

[piao-0429]

Hi! I'm wondering how I can apply a transformation to a trained model (aka output/xxx/point_cloud/iteration_30000/point_cloud.ply)? I found that apply translation can be easy by simply adding an offset to xyz positions, but just applying rotation and scaling to xyz does not work. I have checked that the point cloud is correct, but the rendering result is terrible.