NX8 Create X,Y,Z expressions of a selected point 2

[cucuu]

Hello,

I want to create associated X,Y,Z expressions of a selected or created point. In one of the posts in the forum, JhonRBaker said in NX 9 there's a function named "Measure Point" to do this. Unfortunately we don't have NX9 in my company. Is there any way of doing this in NX8.

For example, i put a point on a curve by percentage or length. I want to create x,y,z expressions for that point and when the curve changes by other expressions, these xyz expressions should also change.

 

[aluminum2]

I would just go to insert->datum/point->point. After placing a point, click on the point in your feature tree and go to expressions. there should be x,y,z equations for it.

 

[cucuu]

Thanks for reply,
It only creates xyz expressions if the point is created due to its xyz coordinates. When i put a point on a curve by percentage, the only expression created is that percentage.

 

[cucuu]

For addition, say i created a point set on a curve, and i want the xyz expressions of all the points of that pointset. That i can not do.

 

[cowski]

Is there any way of doing this in NX8.

Yes, but it might get a little messy.
In the attached part, you will see an arbitrarily shaped spline with an associative point. There is a datum csys at absolute and another one offset from that (in +X, +Y, and +Z). Open the expression editor and pt_x will give the X location of the point. The distance from the absolute YZ plane gives the "magnitude" of the point's X location, the difference between the measurement features gives the "sign" of the point's X location. Change the parameter of the point on curve value and pt_x will update. You can use a similar strategy for Y and Z position.

www.nxjournaling.com

 

[cucuu]

Thank you very much cowski, i think this will solve the issue.

 

[cucuu]

By the way there is an issue in the formulas you sent.

sgnX = if((p30-p36)>0)(1)else(-1) , {p30 is distance to absolute YZ plane, p36 is distance to ref plane}
The sign formula gives negative x coordinate even if it is positive when the point is between the origin and the ref point. For example if my point is at +0.27 to absolute x , and the ref_x = 1, then it gives -0.27, because (0.27-0.73)<0. I updated it with the below formula if anyone needs.

sgnX = if((p30-p36)<0&&(p30+p36)!=1)(-1)else(1)

Thanks again.

 

[TaylorAnderson]

Somewhat similar to cowski's method, though maybe a bit simpler...

The thing I've done occasionally (prior to the availability of the Measure Point command you mentioned) is to create a set of three datum planes way out in the negative X, Y and Z directions, at a reliably distant spot that will always be on the negative side of the design. (Depending on your design, that may be 100mm, or 10m, or 100m... You can choose, but set up one common "offset" expression, and use this to drive all three offset datums.) You can then set up an individual Distance Measurement between your point and each of these datums that will:

a) always have a positive resulting value
b) be at a known simple offset from the origin

So the expression logic is far simpler.

So for example, if your point is at (23mm, 78mm, -90mm) and your datums are all set up at -1000mm (for example) then your raw measurements would be:

Xmeasured: 1023mm
Ymeasured: 1078mm
Zmeasured: 910mm

Sutracting the original offset (which should of course be a common expression from the beginning) from each measurement you should get the correct values:

Xfinal = Xmeasured - OFFSET = 1023mm - 1000mm = 23mm
Yfinal = Ymeasured - OFFSET = 1078mm - 1000mm = 78mm
Zfinal = Zmeasured - OFFSET = 910mm - 1000mm = -90mm

Does that make sense?

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

 

[cowski]

Much better, have a star!

www.nxjournaling.com

 

[cucuu]

Yes it is much better since it halves the required measurements. Than you Taylor.