"sg.h" header
 

When should we use "sg.h" header in the code??

sg.h header
 

I also want to know the same?

Its given in the UDF Manual. Mostly in Connectivity Macros section

Hi, Its a late reply...but somebody will be helped I hope.
If you want to access details of cells or faces like the inter-cell-centroid distances or the cell and face centroid distances or even the diffusive flux terms, you must include the sg.h header files since they are not available in the udf.h.
please find the link below to be clear:
http://www.afs.enea.it/project/neptu...udf/node99.htm