for a long tank,i want to mesh it with variable grid that is small grid for one side and large grid for other side.I meshed one edge with ratio 1.5,but it don't work.what shall do with my case?

I have had this problem before as well, I solved it by meshing both edges on one of the faces which was to have a variable grid, then meshing that face and then the volume, not sure if this is the quickest method but it worked.

i have tried meshing four edges of one volume, it's also cause mech line from one coner.why? take your ways.should i mesh the volume with the meshed face specified with source face?