Open3dVisualizer runs slowly

[Reach666]

Open3dVisualizer runs slowly in my machine. Through debugging, I found that this line of code takes a long time (about 2s).
self.point_cloud.points = o3d.utility.Vector3dVector(points_3d)

If I change the data type before this line of code, the code runtime will be greatly reduced (about 0.03s).
points_3d = points_3d.astype(np.float64)
self.point_cloud.points = o3d.utility.Vector3dVector(points_3d)