When I took pattern drafting I had no intention of drafting my own sewing patterns. I took classes to understand how it was done so I could more easily modify patterns.
There's no reason a knitter couldn't focus on sewing adjustment materials to learn what they need to and apply that back to knitting.
It's a two step process:
1) Understand the flat pattern
2) Add shaping with darts.
Darts for knitters are accomplished with short rows or internal increases and decreases.
There are lots of free resources that we can use, my library has all sorts of books on fitting. YouTube has an amazing amount of videos available, just search "pattern drafting bodice" view a few of the basic versions and then move on to:
This video explains darts and you can see why shaping is necessary for good fit.
If you do create a basic "sloper" it could be compared to any pattern schematic if you create a paper mock up.
Here's a great article from Threads magazine. Their image below gives you the highlights.