hi barry,

if i understood you right, in your last post you were talking about working on doing the root fillet. the file you wanted a link to awhile ago has some retention geometry in it. you could use a shape similar to that to attach the blade to, then try to fillet it. i have found this geometry to be about the best to go with. it fits the most blades in it. i have been manually making it, as it varies blade to blade. i'm not entirely sure if you could automate it. i'm not sure of exactly what factors go into sizing it. i found rhino messes up the geometry a lot in subtle ways. the best way to get rhino to accurately make it was to extrude a whole cylinder and then do a boolean split with those funky red curved surfaces. anything else i tried would be malformed. which is typical rhino. that's why i am looking forward to switching to moi. but this should give you an idea of what sort of retention to connect the blade to. unfortunately, simple pie shaped pieces often don't allow you to fit all the blades. so you need that weird cut to get a lot of blades to fit onto a hub. this is the same link as before, just posting it again for convenience. let me know if you have any questions.