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Calculate the volume of the air/free space inside a complicated assembly?

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handsupdb

Mechanical
May 8, 2014
7
I've got a quite complicated assembly, it's an enclosure that has components/parts inside that take up space. I can't provide incredible specifics due to the NDA at my company, sorry :(

My objective is to calculate the area of the air or free space left inside the complete assembly for a flow analysis later on, and keep the method so that I can use it again on new variants of the assembly.

My idea is to create a block that encloses the portion of the assembly im concerned with, and subtract the assembly from that block. However, I'm not totally sure how to without individually doing a boolean subtract of each part from the block (with over 4000 of them, this is pretty much undoable).

I was thinking about a way to unite the entire assembly into a single piece, however using simplify assembly I lose the interior geomtry (therefore that volume) which is pretty useless.

Binary unite would require me to individually unite each pair of bodies, again pretty much undoable.

I'm wondeirng if there's any simple way to turn the assembly into a single body that I can use as a tool body on the block I create? Any help would be greatly appreciated.

BTW, I'm new to NX but know ProE/Creo and a chunk of Solidworks.

Thanks!
 
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have you looked into using the space finder command? May not be accurate enough but We use it to rough estimate oil volumes.
 
I have not at all! I just took a look and it may be just what I need, I'll edit this with my results!
 
Alright well the space finder command does what I need, but not fully. It runs into an error "Boundar is not closed or start point is out of bodies."

Any tips on selecting an appropriate start point?

My assembly isn't an airtight/completely sealed setup (there is some air spacing on screws/some joints). Possibly create a thin shell that encloses the outside of the entire assembly and add that? That way it closes the boundary?
 
Yea, it might close the boundey, you may also want to try a zero thickness sheet body to see if that works.
That way the volume won't be affected.
 
I tried a zero thickness body sheet, and now I'm facing a warning about my interior point:

"Start point is on the boundary of bodies."
 
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