If you post your file I’ll take a look. Looks like the way you’re defining the surface doesn’t give points coinciding with the corners.
To make a hexagonal membrane from quads, an arrangement like shown here can work well:
If you post your file I’ll take a look. Looks like the way you’re defining the surface doesn’t give points coinciding with the corners.
To make a hexagonal membrane from quads, an arrangement like shown here can work well: