Many thanks @ptrblck this did clear up a lot of my doubts about 3D labeling. I see that the output has 2 channels whereas the target has only 1 channel. I was under the impression that they both needed to be of the same dimensions. I see that is not the case.
So I dont have to do any special processing with my label data as they are already in the required format (A zero tensor with 3D gaussians on the points of interest).
Can you please clarify what is the purpose of pred.unique() in the above code. As with or without this line I am getting the same result.
Thanks again