hi, I don’t believe you have to modify the source code to adjust the gravity,
if you use this link :
https://docs.unrealengine.com/en-US/…ent/index.html
then press clt + f, and search for gravity, it will high light about 7 options that will allow you to adjust the characters gravity, I think this might do everything your looking for?
search for “mass” will yield about 3 options that might also help.
God Bless you. May Jesus Christ be Charitable unto you.
John 3 : 16, google it, its cool.