how to export *.pth to *.onnx?

[OPhD-hahao]

First of all, thank you for sharing this repository. It has been a great help for the project I am currently working on.

I am currently training a modified version of the PointPillars model with OpenPCDet, and wondering how to convert the pretrained weight file (*.pth) obtained from this into *_pfe.onnx and *_backbone.onnx files.

Best regards,