Hi. I've run into problems writing HDF4 files and would appreciate help from anyone with experience. I would like to create one Vdata and have it contain multiple fields. I've sucessfully created the Vdata and named the fields using HDF_VD_ATTACH and HDF_VD_DEFINE but when my code reaches the various HDF_VD_WRITE it generates an error as it tries to write to the various fields. I'd appreciate any help on how to accomplish this. thanks.