Can't divide by expression inside scetch 1

[Brianpore]

So I have this wonderfull scetch and I am trying to use a percentage of the OD to keep the distance the same when I change the OD.

My OD expression is p46=4.114

What I would like to do is p178=(4.114/p46)*.99

Why when I try to do this it gives me an error that says "Dimension error" "The units of the formula are not consistent with the units specified.

Thanks!

 

[velto]

Brian
I don't understand why you don't use p178=p46*0.99

 

[Brianpore]

Velto,

The reason I can't use p178=p46*0.99 is because I am reverse engineering something. So my initial value of p46=4.114

I am then going to change p46 so p46 in the end might be 5

If I use p178=p46*99 for p46=5 my answer would be 4.95, but my value should be 1.203 using p178=(4.114/p46)*.99 as that is about a 20% increase.

Hopefully I explained that ok.

 

[JohnRBaker]

OK, it appears that with your approach, you're trying to make p178 a quotient, and as such it can NOT have any units. The problem is that when you're inside the Sketcher, ALL of the Expressions associatied with Dimensions will have a Dimensionality of either Length or Angle, which means that they will have units associated with them. That being the case, you can't set a Length/Angle Expression (such as p178) equal to some constant divided by another Length/Angle Expression (such as p46) which also has units, because the 'units' won't match, hence the error message that you're getting.

What you're going to have to do is go into the Expression Editor and create an expression which has a Dimensionality of 'Constant', something like XXX = (4.114/p46)*.99, and then set p178 equal to XXX (BTW, it's OK for an expression that requires units to be set equal to an expression that has NO units).

Give that a try as I think it will solve your problem.


John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

 

[Brianpore]

John,

Thanks!!