So from what i understand, in order to change one value from a core def you have to completely redefine the object?
That seems a little inefficient, so I thought i should check my understanding here.
Is that truly the way if i, say wanted to change the name of the food need (i'm not doing this, its a small example), i would have to specify
<NeedDef>
<DefName>Food</DefName>
<needClass>Need_Food</needClass>
<label>new name for food</label>
<description>Food is the amount of nutrition a creature has consumed recently. If it is at zero, a creature will take starvation damage over time.</description>
<listPriority>800</listPriority>
<major>true</major>
</NeedDef>
in a file in its entirety, and update the entire definition if tynan ever changed it?
You don't need to copy the entire file, just the single def. But yes, you need to copy the entire def to change a single value.