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Internal volume of assemblies


I'm looking to calculate the internal volume of a complex hydraulic assembly, which may have some holes to be patched and which will require splitting into different areas.  The intention is to use the volumes for some fluid modelling.


One method I'd seen was to extract bodies and then use Analysis >> Advanced Mass Properties >> Mass using Curves and Sheets.  However I'm not getting quite the volumes I'm anticipating, possibly due to the holes that I have.  I've attached a picture of an example of how it's not what I expect.


What I expect:

Pipe ID = 22mm

Pipe length = 80mm

Pipe volume = 30,411mm^3


The value I got (20,273) is about 2/3 the value I was expecting; am I missing something using this method, or is there a better method that I can use to get the correct result?


It's probably worth adding that I'm using NX 7.5.


Betreff: Internal volume of assemblies

Solution Partner Valued Contributor Solution Partner Valued Contributor
Solution Partner Valued Contributor

Hello LADransfield,


following steps should be also working in NX7.5:


1. "Delete Face" (Synchronous Modeling)

2. Select the inner face

3. Use "All but selected" (Selection group; Top Border bar)

4. Finish Delete Face with OK.


In an assembly, you have the problem that there are no volumes. One possibility is to link the bodies in one part and "Unite" them.


Another way is to use "Simplify Assembly", but I´m not really experienced with this tool. And, I think the "large Assembly"-License is necessary.


Hope it helps, Frank

Betreff: Internal volume of assemblies


Have you looked into using the simplify Assembly?  This should help you in making one solid body to measure the volume.  You need to have the advanced assembly license.


Also you could use space finder to esitimate the amount of oil.  This works well for us.  It uses cubes to calculate the oil voule inside a closure.  Make sure you have your holes filled.

Betreff: Internal volume of assemblies

I've not been using NX long but I've looked into it this afternoon - seem to be getting somewhere Smiley Happy

Betreff: Internal volume of assemblies

Siemens Genius Siemens Genius
Siemens Genius

As @sdeters noted, this is a good use case for Spacefinder... it uses a voxel / cube based model to measure the internal volumes of complicated assemblies



Betreff: Internal volume of assemblies


It doesn't look like space finder has enough fidelity: the cubes are quite large even with the finest settings I can manage without running out of memory so I don't think this will give me an exact enough volume (assuming that the volume it gives me is only the cubes).


I'm also looking for something which will let me split the volume into individual parts as when I begin putting together an AMESim model of the system that's what I'm ideally looking for.

Betreff: Internal volume of assemblies

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi LADransfield,


It’s been a long time since I touched NX7.5 and I do not have it installed anymore.... I got as far back as NX8.5 and I’m not sure to what functions might not be in NX7.5. Nevertheless attached is a movie with an idea of what you could do. The beginning is showing the verification of the Measure Body used in the example - seems like it’s working as expected with your values as well (however this is NX8.5 - not sure to what Measure Body looked like in NX7.5) The example is based on executing the volume analyze in a separate file into which the required interior geometry is linked and prepared. The interior are linked and holes and unwanted gaps are filled in the linking process. The interior linked geometries are joined in my example by Trim/Extend but that might not be available in NX7.5 and you might have to use Trimmed Sheet and Sew to get to the same point. The volume analyze is performed by using Measure Body.


For the individualization of the parts Split Body is used.


Have a look to the attached movie file.


I hope this helps


Best Regards



(view in My Videos)