I have been using the Unwrap tool a bunch more, and ran into a bug today. After selecting a bunch of seams, I needed to select one that was “hidden”. It was behind some other geometry, and in a tight space, and no amount of rotating could get me a good position to select the seam, so I thought to myself “I’ll just switch to wireframe and try to select it that way!”
As soon as I switched to wireframe, all my previously selected seams disappeared and no amount of wrangling would get them back, and using Undo (While still in Unwrap) seemed to select EVERY seam on the model. I think it was probably undoing something from BEFORE I went into Unwrap but doing it while I was IN Unwrap, so that may be a bug as well.
I think the seam selection should survive changing render modes while in the unwrap tool. In fact, I think the seams that are selected during unwrap should NEVER disappear. I posted here a few months ago about having to re-unwrap objects after already unwrapping them, and was informed about “PreviousSeamSelection” and that helps, but I have also had to re-unwrap objects after having closed Rhino, and the previous seams do not survive. They should be saved as a property of the object, and survive closing and re-opening Rhino. Other 3D apps keep the seams with the object. In Blender, when I mark seams and save the scene, the next time I open the scene, those seams are preserved. I REALLY like the unwrap tool in Rhino now that I understand how it works with the render model, but it seems like there is still a lot of work to do.
So to recap:
Bug: Switching viewport render mode wipes out seam selection in Unwrap.
Feature Request: Seams that survive saving/reloading/crashing and not just in the same Rhino “session”