Can you turn negative space into a mesh

Support Modeling
#1

Hi guys,

So I have got this jar that I made in blender. Obviously, it has a empty/negative space in it for it’s content, which will be powder or creme.

Im looking for a way, to turn the negative space of the jar, into a seperate mesh. If i can turn this negative space into a seperate mesh… this mesh will exactly fit the shape of the inside of the jar, and that’s what im looking for here.

I have tried selecting everything on the inside of the jar…but i keep on selecting faces en edges that are on the outside or something. Its not wokring. So i was hoping that theres a clean alternative to doing this…

Thanks!

#2

If you select the outside faces and press H, then those faces will be hidden. Alt-H will make them show again. This will help you find hidden faces without the clutter of the rest.

When you select the faces in the jar, a simple way is to duplicate them, then press P to separate the duplicated faces into a new object.

#3

Just select on of the edge loops of the inner part of the jar and press Ctrl + E and choose Mark Seam

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After that select one or more the faces inside the region you want to have entirely selected and then you either press Space and type in Select Linked or you just simply press Ctrl + L in order to select linked faces that will only be restricted to that region that was determined by the marked seam edge loop.
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#4

Ah that is some great advice guys…thank you very much. This should work now…

#5

My preferred way of doing this is to loop select the boundary (Alt+RMB) hide it (H) and then select a face of the part I want to keep (RMB) and select linked faces (Ctrl+L).
If you have multiple penetrations and/or complex geometry it might be difficult to see where the parts are connected. I like to use grow selection (Ctrl+‘numpad+’) to incrementally select linked, and then watch for where it pops out of the region I’m intending to select.