[gembud] Interpolating levels in GRIB data

Hi All,

I am working with models produced from wind and temperature GRIB data.
(DCGRIB2 produces a .gem model from HT*, HU* and HV* messages).
I am trying to extract point data using GDPOINT at an arbitrary level.
Can anyone tell me how to interpolate?  Or, as an alternative, how can I
create a new grid with finer resolution in the level dimension?

Many thanks,

Mark Hughes
Global Weather Dynamics