Master-Detail: Populate new child record with values from master

Standard Master-Detail page.

1) User clicks, "New" on the child record.
2) How can I populate fields on the createForm1 of the new child record with values found on the master record?

I have my attempt shown below. I have hardcoded the "1", if I knew how to reference the master table primary key in place of the "1", that would be one solution. Using @EncounterBatchID did not work. Is this easy to achieve using a SQL Business Rule or should I look to Javascript or C#?

1 person has
this question