Hi Gili,
i opened the exodus file that you send via mail.
The tets aren’t sharing any nodes with their neighbours.
When i import the file and let the volumes create, i will get a volume for each tet because they are not connected.
I am really curious how your input mesh looks. Are you performing a simulation where the elements doesn’t share a node? Or is it because of the result output?
Or is you solver unmerging single elements when they are damaged enough?
We would either need a way to know the fractured elements and delete or deactivate them from the input mesh. Or the other option would be to somehow create a geometry that can be meshed. But think the a traditional tetmesh will probably not work here for remeshing. And i would either go for sculpt or something like in this post . Remeshing this way has the downside that the input volume size will not equal the output volume size. So we either win or lose tiny volume fractions.