Hello, I have been trying to do some model based definition on this lens part with the DimXpert tool so that I can use TolAnalyst to see how their individual tolerances stack up in a system of lenses. However, I can't seem to get the part fully defined. I can define a basic size dimension for the spherical faces and a location dimension for the center of the radius, but the spherical faces never become fully defined. I have tried every combination of datum features (top, right, front planes, cylindrical portion, flat portion). Not sure if I am missing some dimensions or if this is just not possible in DimXpert. Any help would be greatly appreciated.