question in the paper 3.3

[chrisyan]

Thank you very much for the amazing work! I have a question about the 3.3 in the paper " Note that we do not use any classification
prediction of the pre-trained 2D detectors by default as our main focus is enforcing the 3D detector to learn localizing from the pre-trained 2D detector at this stage."

Here, you are using a pre-trained 2D detector. If the 2D detector is trained on a pre-defined categories dataset, how about the object outside this pre-defined categories? Can those objects still be detected?

Best
Chris