how to define periodic for free type face in hexa meshing
 

I set up the periodic under mesh tab=>global mesh setup=>setup periodicity.

For mapped face block, face periodicity will be made by making 4 pairs of periodic vertices,
however, for free typed face, theirs either less or more than 4 vertices, after making all the vertices periodic, the face block is still not periodic.

Are there any way to make two free type surface block into periodic pairs?

Second question is how to make surface mesh periodic

I ran octree periodic is fine, but i can not control the ratio on both surface and volume. and I noticed that one of the periodic surface have to be in line with XY, YZ, or XZ planes. Is that correct?

then I tried to generate the surface mesh for all the surfaces and then use Dulaunay to fill the volume. However, I check the total elements on a pair of periodic surface, it's different.

How to generate periodic surface mesh?