Output 3D plot as vectorized image (currently it is partial vectorized and partial raster)


After I followed the plotly example (here) and generated a 3D scatter plot, I cannot output a vectorized plot despite I saved as pdf format.

In my pdf output, only the figure legend are vectorized. The 3D scatter plot is still a raster image. I was wondering what should I do to make the output file a complete vectorized image.