Hi!
I would like to know, please, how to substract a solid closed polysurface by a tube, inside it, that is too, a closed polysurface. The radius of the tube has various sizes.
I give you here screenshots. At the end, it is impossible to do it, i have the message that “there is no intersect surface, impossible”.
Can you please help me? 
Thanks so much! 
Rhino does not by default let you subtract solids that do not intersect to make a hollow body like that. The workaround is to select your two tubes, call _NonManifoldMerge, followed by _CreateRegions. That will force Rhino to create a ‘disjoint solid’.
The question is, what do you want to do with this afterward?
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Could you not extend the inner parts through the end of the outer? That is if your looking for the outer to be the keeper.?—- Mark
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Hi Mark!
Yes, i tried too to extend more at the outside the smaller volume, and even, doing the boolean substraction, it says “boolean failed”, as i give you here the screenshot.
That’s only to be done on disjoint solids like the one in your first post, not ones that intersect like in the one above.
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But then, after doing “_NonManifoldMerge”, i am doing"_createRegions", Rhino asks me to choose a polysurface, i click on the all merge surface, and then, after, nothing is happen, do you know why?
Please post the file you used…
Hi!
Doing more long the smaller tube, it seems it is ok!
Like this on my screeshot.
Now, i am going to try what you say about the first screenshot!
At the moment i finish, i post!
Thanks so much!
