Join 2 surface with the result one surface

Hi all!

I have written a script to make a voronoi give the shape of my surface (snake shape)
Now I want to add a part to my surface (the circle) but when I join them it becomes a polysurface.

Anyone knows how I can make it into one surface and keep it as a surface? Else my script won’t work anymore :frowning:

THXforum.3dm (12.4 MB)

Join dos not modify geometry. It tests to see if the surfaces are within 2x tolerance, and if they are it tags them as Joined.
If your two surfaces have untrimmed edges, instead of Joining, use MergeSrf