Roll dimensions. People call it different things, but it's a way of checking angles on a sine plate for location.
(DESCRIPTION) The way of checking a part by putting a pin of known diameter (gage, dowel, core, drill rod, an endmill, whatever...) in the corner of a sine plate against the back rail. Get a zero number over the pin. Now remove the pin and replace it with your part, raise up the "over roll you got from your computer or from an easy formula", that's your location. (THAT WAS FOR THOSE WHO DONT DO ACCURATE ANGLES)
Ok...I say forget the dowel pin, or gage pin, whatever. It's not needed. The sine plate already has a roll, the roll it rotates on.
If you add (1) the thickness of the bottom plate of your sine plate,(2) the distance from the top of the roll it rotates on to the floor of the sine plate where the part sits on, (3) and the distance from the back rail to the top of the roll with the sine plate standing on end. Add those three things to your cad gimmic, or your simple roll dimension program, or your xcell roll program and you will make your life a lot easier.
Now...you will be checking from the surface plate to the angle face(simple). No pin needed. No need to see where the pin is, than add the formula number to it, blah, blah, blah. My way you zero your drop indicator on the surface plate (use gage blocks to stay in drop indicator length range), touch off on the angle, and read the number on the indicator. Cut and dry. More accurate, a hell of a lot simpler, and a lot faster, and less prone to mistake
As a programmer I'd like to provide that number, plus a number identifying the sine plate that number is for.
If you do angles a lot, it will make your job easier. If you don't you just wasted a minute of your life.