mo,
For a rectangular pyramidal hip roof with equal overhangs and a level fascia, you need to work from the gutter line
Start by drawing a line drawing in plan view. Remember to work from the gutter line. I add in the plates as a faint or dashed line just for reference at this point.
Usually I let the main pitch and the size of the building (including the OH's) determine the pitch of the adjacent side. Connect the corners and you have the hip lines. The hip line will not cross the corner of the plates as mike mentioned.
You will also want to shift the hip so the backing cut is not centered, but rather leaves equal depth on each face of the hip (you posted a graphical solution to this a while back that I still refer to).
Last thing you do to the plan drawing is add the jacks. If you use the same spacing on both sides, they will be staggered along the hip. alternatively , you can change the spacing to make them hit the hip in pairs.
To get the pitch of the adjacent side, determine total rise from gutter line to peak on the main side. Solve for pitch using total rise and adjacent run including OH.
Now you have everything you need except the HAPs. You have to choose one side's hap and let it dictate the other sides hap. It can be give and take between the two sides so that you don't take too much out of one or too little out of the other. I start by assigning the tallest HAP i can live with to the higher pitch side. then, using the runs of the jacks to the plate and the pitches, i see what that gives me for the shallow side. If it isn't too deep a notch out of it and I can come down a little, I may do that. The alternative for different HAPs is different plate heights, but that is a tough one to make look right in exposed framing. In stick framing it's common to raise the plate level on the steep side to make the HAPS the same.
One place to keep an eye on is the Hip where it crosses the plate(s) and forms the overhang. You will probably want to reduce it's depth after it crosses the plate line because you will be taking a good bit out of it to meet your two HAPs (assuming the hip is deeper than the jacks). this area can look funny if you aren't careful.
Sketchup is a good way to model this to avoid funny looking stuff.
