Volume source reconstruction

Hi, experts, I tried to compute the head model with a volume head model, and I used the option 'load from a file' to specify my volume source grids, however, I got the following errors:

For BEM, all the surfaces must be closed and they should not intersect each other.
Verify our loaded surfaces, as the message error clearly indicates:

Interface "1" is not closed !

Ok, I have found that the BEM surfaces were not created, thank you!