Adding a check to an expression 3

[flam04]

How do you set a limit of travel for an expression in NX10. I have an expression that needs a limit of +.375 to -.375.

 

[cowski]

You can use a secondary expression to check and limit the value of an existing expression.

if(input < -0.375)(-0.375)else(if(input > 0.375)(0.375)else(input))

The above expression formula will check the value of an expression named "input" and will constrain the output.

www.nxjournaling.com

 

[TaylorAnderson]

We don't physically limit the bounds of an expression in NX (yet) but we can add checks that will tell you if you're out of bounds.

The easiest way is to select an expression, and choose "Add a Check" from the MB3 menu. (There's a button for this at the bottom of the Expressions dialog too, but the MB3 is a bit more direct.)

If you've not previously created any requirements in your part, choose "Create New Requirement", and fill out the form:

You can choose a severity here (Error, Warning or Information) and choose from several ways of defining the requirement. Note that the requirement is formulated as a positive statement of what the value should be, as opposed to a description of the bad case.

Once you press APPLY in the Expressions dialog, the check will start to give graphical feedback in the expressions dialog:

...and in the Part Navigator:

This requirement and accompanying requirement check can also be examined, edited, etc. in the Requirements Validation HD3D tool:

...and if the expression is directly related to some geometry on the screen (feature parameter, or measurement expression, for instance) then it will automatically start to add HD3D tags to the screen whenever the Requirements Validation tool is active:

...and if it's not directly related to some geometry on the screen yet, you can tell the tag where you'd like it to appear when things go wrong:

And yeah, there are many more cool things you can do with this. ;-)

And last but not least, you'll be pleased to know that no extra licenses are required, either... This is all part of base NX.

Does that help a bit?

Taylor Anderson
NX Product Manager, Knowledge Reuse and NX Design
Product Engineering Software
Siemens Product Lifecycle Management Software Inc.
(Phoenix, Arizona)

 

[flam04]

This worked pretty good, not all that hard once you know what to do. Thanks Taylor.

 

[TaylorAnderson]

My pleasure!

Taylor Anderson
NX Product Manager, Knowledge Reuse and NX Design
Product Engineering Software
Siemens Product Lifecycle Management Software Inc.
(Phoenix, Arizona)