Hey, we’ve released the Fill tool which can be used in exactly these situations.
While it’s not surfacing as you might know it from Rhino, it’s a tool that should let you create forms that weren’t possible before in Shapr.
We are still working on improving this tool and we’ll soon add a couple of new features like bridge curves that will make it more powerful.
You can read more about it here: 26.190 - Introducing Fill Tool (Beta)
Give it a try and let us know what you think!