Volume of a solid body
Volume of a solid body
(OP)
NX4..
I have been observing when the geometry of the solid body is built from a complex splines and shapes, the volume value changes..
for example, if the volume for body when it is one single solid is xxx.xxxmm^3, when you start splitting this body into multiple pieces, the consolidated volume starts to vary..
Is this a bug in volume calculation in NX?
I have been observing when the geometry of the solid body is built from a complex splines and shapes, the volume value changes..
for example, if the volume for body when it is one single solid is xxx.xxxmm^3, when you start splitting this body into multiple pieces, the consolidated volume starts to vary..
Is this a bug in volume calculation in NX?





RE: Volume of a solid body
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Volume of a solid body
Best Regards
Hudson
www.jamb.com.au
Nil Desperandum illegitimi non carborundum
RE: Volume of a solid body
After the initial post above, I decided to test this in NX 6.0.4.3 using a very large and complex model of a casting (413 features, 901 faces, 2012 edges and 3.8 meters long x 2.4 meters wide x 0.7 meters high). I first measured the volume of the original model, which I saved. I then performed a 'Split Body' operation, cutting the model basically in half, and measured the volume of each half and then added these two values together and compared it to the original volume, and the difference was LESS than 0.01%. Close enough for government work
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Volume of a solid body
The volume behavior for a body built from a complex B-surface mesh in NX6 is also same.. there is significant variation in the volume value
RE: Volume of a solid body
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Volume of a solid body
Personally I had cause rather recently to design a product of quite irregular shape which itself needs to be suspended hanging freely from a cable. Using measure body tools I optimised the design for balance and sited a hole on the centre of gravity. We then made accurate prototypes that hung from that string with the top face so flat an level that it would hold a bead of water steady. We all trust the system to be accurate and intellectually accept it, but is sure is fun to have a working example.
Best Regards
Hudson
www.jamb.com.au
Nil Desperandum illegitimi non carborundum
RE: Volume of a solid body
I have had this happen to me on several occasions, with the hindsight of experience, we now have the measurement accuracy locked at a site level.
0.999 seems to give a good trade off against accuracy and performance for our components which contain free form surfaces.
On a side note, we have seen the weight calculation become more accurate as we have migrated from v16 > v18 > NX2 > NX4 (all though some users oddly believe that because the new value is different, it must be wrong!!! Users, who'd have them...)