It looks really strange, but I have to use all these versions of Rhino. Why?
Nowadays I use Rhino 4 only for splitting complex surfaces that Rhino 5 and 6 fail to do,
I use Rhino 5 as a main tool with some plugins, as T-splines for example…
And I use Rhino 6… I like some beautiful improvements but I cant finally migrate on Rhino 6 because it is not compatible with some older plugins and fails in splitting complex surfaces.
Here is an example of surfaces that can be splitted in V4 and not in V5-6. splitting troubles.3dm (8.8 MB) if someone is interested.
well, that`s why I have all Rhino 4, 5 and 6 installed