dodos Thank you for your feedback! I think you're right, and we should improve the functions so that it's easier to set the exact mesh vertices. In fact, we have received many requests for features such as the ability to add mesh vertices to more precise positions and mirroring, which is often used when creating 3D models, and those ideas in our roadmap:
EsotericSoftware/spine-editor274
EsotericSoftware/spine-editor77
By the way, in Spine 4.2, the Auto Snap feature was added to automatically snap to the center of the edge. The following video shows the snapping behavior:
This makes it much easier to add new vertices and edges to the center of an edge without having to use the Generate button. (You can disable snapping by holding down the Shift key.)
If you haven't tried 4.2 yet, give it a try.
