It's safe to assume that each ring is equal in measurement. Limited to only a flat plane, for calculation purposes, simply subtract the star circle diameter from the shield diameter, then divide that result by 6 and you get your answer.
There really is a fair amount of wiggle room in the measurements that will still result in a "movie accurate" proportions. Remember, there were several diamter shields used in the films, at least 24", 25", and 26" ... so it really is about getting the proportion of center circle to ring area. As you'll see in the beginning of this thread I did a bunch of photo analysis. Not saying I nailed it, but what I have found is a 25" or 26" shield with a 9.5" or 10" circle seems to look real close. And yes, then equally dividing the remaining "ring area" into three equal rings. My favorite dimension set, because it looks spot on and is easy to remember is this: 25" shield – 10" center circle – each ring 2.5". It's what I've based every shield I've made on. Your mileage may vary
I don't know if any knows this but according to a YouTube video I watched the efx company actually got access to the original molds from the avengers movie so if any has one I would measure it.
Yes, efx produced their shields from a production stunt shield from The Avengers. They're were several shields in different dimensions used throughout the various films.
And the measure of the depth of the shell (curvature) according to the measures discovered would be 26 and the depth ?????? These measures are the same as the civil war movie ?? And invernal solider ?