Is it possible to create one natural watertight mesh based on the boundaries of other shapes?

Hello, I want to make it from left data to right data.
Looking at the shape, I don’t think made the Mesh arbitrarily, but I think positioned some data and cut it and make naturally.
I’ve completed some data and then cut it, but I couldn’t make it a natural one watertight mesh.
Please give me some advice.

Looks like something for VESPA:
https://gitlab.kitware.com/vtk/meshing/vespa

FYI @Charles_Gueunet

Hello @joo94372

Indeed, Vespa may help you here. We presented this library / plugin here. I would suggest to have a look at the alpha wrapping algorithm, witch ensure a closed manifold as a result.
If your initial mesh is manifold, maybe the Hole Filling filter may be enough (and faster) to close your mesh.
You may get more information looking at our webinar.
Do not hesitate to look at our release page to download plugin already compiled for various verions of ParaView (linux only).

Best,
Charles