First - Welcome to WTP forums. I have been using the software for over 10 years and I can say measurements are correct.
What type of set up are you using to cut your segments?
Jerry Bennet Seg-Easy method is one of the popular ways to cut segments.
- Here is a link to making a basic wedgie sled
Wedgies (segeasy.com)
Another link to his videos on his method and its possibilities.
Segmentology (segeasy.com)
There are a lot of factors than can cause a segmented ring to end up with gaps during construction.
- Your stock you are cutting the segments from needs to have parallel sides.
- keep the fence clear of dust/shavings so the stock can sit flush against it.
- a good cutting sled and blade is important. (I use a 80 tooth blade)
If the gap is not to wide you can build half rings and then sand the two halves on a disk sander to make for a perfect edge fit.
and don't get discouraged. I still get rings that don't come out perfect and need to be adjusted or redone.