Hollow eggshell with 3" thick shell from outer and inner Ellipsoids

Rhino Rhino for Windows
,
1

I have one Ellipsoid fully contained within another. The offset between their outer surfaces is uniformly 3". In other words, the outer surface of the outer ellipsoid does NOT make contact with the inner.
BooleanDifference:
I tried to Boolean difference the two to create an egg hell with thickness to the shell. BUT when I execute “BooleanDifference” nothing happens with prompt ‘Surfaces to not intersect’
Can’t BoolleanDifference be used on one solid within another to hollow out the larger ? If so, how do I turn both the outer and inner Ellipsoids into solids so BooleanDiff will work ? Suggestions ?
ID: 729b75ee-16e1-4ea2-8709-f52db2f8e57c (8549)
Object name: (not named)
Layer name: Shell::Outer
Render Material:
source = from layer
index = -1
Attribute UserData:
UserData ID: 3BDD1473-50E9-4838-8F17-8F1B8EB291F4
Plug-in: Rhino
description:
saved in file: yes
copy count: 1

Geometry:
Valid surface.
closed surface.
NURBS Surface (rational)
“U”: Closed degree =2 CV count = 9 (0" <= U <= 6’3-1/2")
“V”: degree =2 CV count = 5 (-1’6-3/4" <= V <= 1’6-3/4")
Edge Tally:
1 seam edges
2 singular edges
= 3 total edges
Edge Tolerances: all 0"
Vertex Tolerances: all 0"
Render mesh: 1 mesh 7605 vertices 7424 polygons
Created with quality meshing parameters.
Analysis mesh: none present

2

@Charles_Cary
Rhino does not make Hollow solids so to speak. I have run into this at least one time myself.
Someone said also that you can make a small hole in the object and that is a pretty good work around.

Just one of the refs on the forum about this topic.

3

Hi Charles - what is the goal of having such an object?

-Pascal

4

Hi Pascal: Thanks for the prompt reply. I am trying to create an architectural membrane shell thru which windows and doors can be punctured?

5

Thanks Ryan for the prompt reply,

6

Hi Charles - in that case I’d make a solid to start with by BooleanUnion of a small cylinder to the inner shell so that it protrudes through the outer one, BooleanDifference that from the outer - basically what Ryan suggests above - to get a solid you can deal with using Boolean operations for your windows etc. The hole can be removed later if it is not something you want, or it can be consumed by one of the windows .

image
image904×535 64.6 KB

-Pascal

7

Thank you both (Pascal & Ryan) for the prompt reply,

  1. I tried Pascal’s Cylinder (bellybutton) graft (BooleanUnion) on the inner Ellipsoid.
  2. Next I did your Boolean Difference Outer - Inner and got the desired hollow shell. Which looks good from the outside in and from the inside out.
  3. Finally, I punctured some solids (rectangular solids) thru the shell (windows) with Boolean Difference and that worked fine as well. Excellent. Thanks
8

BTW: I did not solve this…Pascal did…
My apologies for hitting the wrong Solution button…