Closed Surfaces


(0613026797) #1

If I create a prism from surfaces and it is fully closed, will Rhino automatically fill the shape to make it solid?

(Michael Pryor) #2

What do you mean by fill? A fully closed shape is considered as solid but if you trim it it will be hallow.

(0613026797) #3

Like I have a shape that is made from surfaces and it’s closed. Does Rhino make it a solid or is it just hollow?

(Michael Pryor) #4

It is hallow (isn’t that how most software works?) What makes it solid depends on whats interpreting it. For instance if you were to 3d print that object the printing software and printer would determine printing it as solid. Or if you were to clip it with a clipping plane you can have it visualize as solid (solid hatch at cut) ect.

(0613026797) #5

So even if Rhino does not make it solid, when I print it, it will become solid.

(Michael Pryor) #6

I don’t think any software except the printing software can determine that. Any printer I have used always had software to determine how to print and let you set thicknesses (shell thickness, completely solid, shell with a lattice infill, ect). Usually you will print a shell with thickness and the inside will be some kind of lattice, there is no point (usually) in printing completely solid as it is a waste of money and material.


(0613026797) #7

But if I set the thickness just right, it will print like it is solid, because I need to print something to support my desk.


A “solid” is just a collection of surfaces that fully close in a volume, there’s no definition of what’s “inside” it.

If you print it, you’ll get a filled solid because that’s how it knows to interpret the slices of the model.

(Michael Pryor) #9

Again, depends on what and where you are printing it. The software for the printer should have settings for that. Or if you are outsourcing it then you can specify to the printing company. For instance Shapeways will let you specify how you want the object printed.


Yes it will, if you have a closed polysurface in Rhino and save it out as an STL file you can print it. I do this all the time. I have a 3D printer at home to print small prototype parts.

Just make sure you save the STL with high quality mesh settings, otherwise the part will be faceted since the mesh is a collection of flat surfaces.

You can print it as a solid if you want, but you are much better off printing with 2 or 3 outer shells and infill. It uses less plastic and will print faster.


I think you just need to make a hole somewhere in this case.

I don’t think surface solids have concept of voids.

The setting for the printer is percentage of filling and likely not controllable by wall thickness…

It’s just a added support so printing can be done in 3D space and not lose to gravity.