An internally hollow entity

May I ask if in Rhino 8, closed multisurfaces can be created with push-pull to create internal hollow solids? (Pushing and pulling a single surface can obtain an internal hollow solid) - as shown in the figure.

No, Rhino doesn’t have a way to indiciate that two non-intersecting surfaces (or solids) are supposed to represent a hollow inside. To make a hollow, you need to have something connecting them, such as a hole drilled in the part.

Can you tell me more about why you want to represent a hollow object?

there is similar topics

found this one - but there was another one…

ok found one more…

one more

Yeah, the question has come up for as long as Rhino has existed. But I’m curios if @CTQCTQ has a use case that we haven’t heard of before (not that it will make it any easier to implement).

@brian Yes, in Rhino 8, I first created a sphere and then used the PushPull command to offset a certain distance, creating a hollow solid. However, this situation seems to only apply to a single surface and is not useful for multiple surfaces (such as the cube of a shell in the figure).

Ah, ok, then this is more a curiosity than “I need to make hollow objects”. It’s true Rhino just doesn’t have a way to represent that kind of object.

@Tom_P Yes, the BooleanDifference command does not work on non intersecting entities.

@brian Although Rhino does not support internal hollow solids of closed multisurfaces, they can be created through Rhinoinside import. As shown in the figure.

Yes you can make such objects in Rhino using NonManifoldMerge but the situations where such a feature is actually useful and not an error are extremely limited. What you are doing here is a pointless academic exercise. THERE IS SO SUCH THING IN CAD AS A “SOLID.” It’s all surfaces. There is nothing actually “inside” a solid. They are ALL hollow. The whole concept of “solid” modeling is an abstraction at the layer of the interface.

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