Open Closed Polysurface Solid

For the year and a half I’ve been using Rhino I’ve received and taken at face value the pop-up message “cannot turn on points on for polysurfaces” if I attempt to do so. Today I learned the valuable piece of info that we can edit points on polysurfaces (just not with "PointsOn*/F10) with ctrl-shift and – if it’s a closed polysurface – SolidPtOn. I suppose I’ve missed abundant documentation of those latter two commands, but I thought I’d point out that the combination of that error message and some terminology on the site* may be misleading.

*If I now understand correctly: The reference in the documentation to “Closed Solids” is redundant, right? A “Solid”, “Closed Polysurface”, and “Closed Solid” are synonymous? If so it’d be really helpful if the term “Solid” (or Closed Solid) appears in What right next to “Closed Polysurface”. If so I’d have figured out quite a bit of valuable info a long time ago on the fly.

Not really.
Rhino is a Surface modeler, not a solid modeler.
We’re using the term solid to mean that your polysurface is “closed” (water-tight), and the surface normals have been ordered to point away from the enclosed volume.

So a “closed, solid, polysurface” translates in NURBS terms to mean the object is water-tight, it has had it’s surface normals ordered, and it is made from more than one surface.

Thankyou John.

Do I need to understand how a “closed solid” differs from a “solid” (if it does)?

Here’s a closed polysurface that isn’t “solid” because it has a nonmanifold edge.

Nonmanifold.3dm (59.0 KB)

Thanks. I’ve never had to attend to manifoldness yet in my work. I guess I’d better look it up again. At one point I knew what it was.

So a closed polysurface is different from a solid. Thankyou.

Does “closed solid” differ from a “solid”? Is there such a thing as an “open solid”?

See if this is helpful:
rhino_basics.pdf (2.5 MB)

Thanks John, it is helpful. I feel familiar with most of it, but there are parts I definitely need to review.

It’s good to have my understanding confirmed in what you just linked to: “Solids are surfaces or polysurfaces that form an enclosed volume.” I encountered the term “closed solid” frequently in the Rhino online help materials today, which made me think there was some kind of solid that’s not closed. That got me questioning my understanding of Solids – which was in fact pretty, well, solid.