VOLUME NX3

[TomMtz]

Friends

I tried to use volume values in the expression chart for calculating a height in other sketch (h=Vol/Diam^2*Pi/4)however when I change other dimension, the program launch an error message and all the archive "die".
Some one of you combine volume values in a similar case?

Thanks for your help.

 

[JohnRBaker]

It works OK for me, but just to make sure that the formula evaluates correctly I tend to overuse parentheses so my expression reads:

h=Vol/(Dia^2)*(pi()/4)

Anyway, attached is a simple model doing what it appears that you are asking about (edit the size of the Cylinder and the sketch updates).

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.

 

[TomMtz]

John

I wrote this formula and still launch: "Error recovery completed for the following error: There is an object which depends on itself", it happens when I change a value from other sketch.

 

[TomMtz]

John

I omit some steps for my question:

1.-I made a sketch (1) (rectangle)
2.-revolved this feature
3.-calculate volume
4.-add value in an expressions chart
5.-I made other sketch (2) (rectangle)
6.-apply formula to calculate height using the calcutlated volume (h=Vol/(Dia^2)*(pi()/4))

When I change other value in the first sketch the program launch the error message.

 

[cowski]

If you are sketching 2 rectangles, where does the value of 'Dia' come from?

 

[JohnRBaker]

This sounds like a circular reference, i.e., you're attempting to edit something based on some value derived from the object you're editing.

From looking at your equation I get the feeling that you may be trying to create a 'cylinder' whereby if you edit it's diameter, that you want it's height to change based on the volumn change which resulted from the change in diameter. Sorry, but that won't work.

Now if this is an attempt to 'optimize' some aspect of a model, there are ways to do that, either by purchasing the 'Optimization Wizard' (and extra cost item) or by using the 'goal seek' feature in the Modeling Spreadsheet (which is a 'freebie').

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.

 

[TomMtz]

C

when I drew the first sketch I add width and height to calculate volume.
In the second sketch I only used the volume for the first sketch when the sketch was created.

 

[TomMtz]

John

Thanks for your help, and its a shame that NX3 doesn´t work in this aspect.
I will try to change the modeling estrategy.

Thanks a lot for your comments

Tom

 

[JohnRBaker]

Since your model sounds very simple, could you upload a copy so that we could see exactly what it is that you're trying to do?

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.

 

[TomMtz]

John

Sorry, but in the company we can´t send files in our e-mails. (law restrictions).
But I´m glad whit your help.

 

[JohnRBaker]

Well look at the part file I posted and try and figure out what it is that you're doing which does not look like what I did.

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.

 

[TomMtz]

John

I have the solution, instead of using a circular reference, I wrote:

(((DIAM1)^2*(pi()/4))*LONG)/(DIAM1*2)^2*(pi()/4)

And it works very well! instead of using the volume from expressions chart, those commands calculated de volume for the first sketch and height in the other sketch without corrupt the file.

 

[JohnRBaker]

Are you saying that the Expression 'DIAM1' is used in both sketches?

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.

 

[TomMtz]

John

DIAM1 - ONLY IN SKETCH 2 to calculate volume of sketch 1.

Thanks for your help. its time to leave the office

See you

Tom