Converting Pytorch (.pt) Segmentation Model to ONNX for the Nvidia Jetson

Question

This question is two-fold:

1. How do you convert a pytorch segmentation model to ONNX. Specifically, I am trying to convert the VGG-16 model from this github repo( https://github.com/khanhha/crack_segmentation/tree/e924b6a3632134848b993c68e7295b1aae92ce28) to ONNX to easily optimize with the Jetson TRT. Is there anything different that a segmentation model requires than a simple object detector/bbox model?
2. Can I do this conversion on CPU, a.k.a. load the pytorch model to cpu and then convert it to onnx, and then load the onnx model to gpu? I want to make sure loading the model to CPU in the conversion phase doesn't change the actual model that's being converted.