Problems encountered in improving the pointpillar model

[Allcaros]

What is the feature?

I have conducted the default pointpillar training according to the official documentation. Although there are some differences in the results, they are acceptable.
The problem I encountered was that when I intended to use other model components in mmdet3d, problems of varying degrees occurred. It took me a long time to get the code running, but the result was disastrous. My idea is to use the centerpoint model and the centerpoint_head detection head to replace the original components of pointpillar;
Now when I start thinking from the beginning, I feel that there seem to be some problems in many aspects that I have overlooked. If you can provide some ideas, I will:

1. I realized that after generating the.pkl file using create_data.py, a kitti_gt_database would be generated. This seems to be a folder for increasing the dataset, but I haven't used it. Maybe do you have any ideas for me to use this folder correctly?

2. In the default model code, there is a parameter called use_ground_plane, which is set to True by default. However, when I run it, it prompts me that there is no related file. So, I simply set it to flase. When I started thinking from the beginning, I realized that this file should be used to constrain the ground target To enable different category targets to be better positioned for learning, if I want to avoid the above-mentioned error reports, where should I download the relevant use_ground_plane file, and what should the training content or dataset placement look like?

3. The results after I replaced the detection head are as follows. I want to know why the ap of the car category is so low when there are so many of them and they are so large in volume. What I can think of is that kitti does not provide a center point coordinate annotation, so such large targets cannot return to the center point and thus cannot be detected. Maybe you have a better idea. Please tell me.

4、Theoretically speaking, it is feasible for me to replace it with components of the centerpoint network. But why is the result so bad? Maybe I need better code optimization, but currently I doubt the compatibility issue. Is incompatibility worse than feasibility?

If you have better ideas or other answers, please let me know. Thank you very much

Any other context?

No response

[Allcaros]

I have learned about the first question regarding kitti_gt_database. If you have any clues, please help me provide clues for the subsequent questions，thanks