I tried Gem Cut Studio https://gemcutstudio.com/ for the free trial and liked it enough to make the purchase. It works differently than GemCadWin, but I’ve used it regularly and have now found it to be much easier to use than GemCadWin. One of the features I like best is the optimization. I can take a design for any material and optimize it for the material I want. The angles are all changed automatically, and it even displays the raytracing data. For those of you with .gem files – Gem Cut Studio reads those as well as it’s own files, .gcs. I doubt that I’ll ever go back to using GemCadWin.