Twisted sweep

[vitulin]

Hi,

i hope you can help me with the following problem. You would have a oil dipstick, which would be general 3D curve spine. And you would need to create twisted section on it. In proe, you would do it the way, that you would simply draw a line in the sketch and constrain it with angle. And than you would do it as variable parameter for example angle = sin t...where t would be 0 to 1 of the curve. Do you have any suggestion how to do it in UG?

Thanks
Vit

 

[JohnRBaker]

When asking questions about specific NX functionality, PLEASE include the version of NX that you're running!

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/

 

[vitulin]

Nx 4,02

 

[hudson888]

Vit,

Sweep the section along using the line as a guide curve and a tolerance of zero. Use and angular law method with a linear type and the values 0 to 360*(number of turns).

Best regards

Hudson

 

[JohnRBaker]

Assuming that you have NX 5, attached is an example using exactly the procedure that your described.

There are 3 elements in the model, a Yellow line that acts as both the primary path of a Swept Body and as the base line for the Law Curve controlling the angle of the twist. A Red sketch curve representing the location and angle of the twist. And a profile sketch of the shape being swept.

The function you use is Swept Surface, using a single trajectory curve and using an angular Law for the Orientation and using a Law Curve to control the angle.

Note that this approach can be used with virtually versions of UG/NX going back 10 or 12 years.

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/

 

[vitulin]

Hudson,

to be honest... I dont know, how and when I should use the law method...Well, maybe I have found it...I tried to use swept and it seems to work )

Thank you very much...
Vit

 

[JohnRBaker]

OK, here's an NX 4 version.

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/

 

[vitulin]

I wonder, if you can also control the other dimensions. Lets say length of the line?

Thanks
Vit

 

[vitulin]

thank you John for the model... As already sad, can you also control the length?that would be very beneficial.

Regards
Vit

 

[JohnRBaker]

The length is controlled by the length of the trajectory curve, in this case the first line. To make it easier to understand, link the overall length of the Sketch to be same as the length of the trajectory. For a example of this, see the improved attached file. Open the part and then open the Part Navigator and expand the section titled 'User Expressions'. From these expressions (double click the expression to edit it) you can now control the overall Length, the angle of Twist, and the start and end points of the Twisted section.

Have fun.

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/

 

[JohnRBaker]

And before anyone asks, yes you can have the sweep follow a path other than a line.

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/

 

[vitulin]

I dont know, if you understand it right...I thought to change the length exactly the way, you are changing the angle...for example length going from 50 to 100 along the curve...
Thanks
Vit

 

[JohnRBaker]

The length of the Sweep is NOT controlled by the Law Curve Sketch, only where the twisted section starts and stops and what the angle of the twist is going to be. But since these are NOT automatically linked, that's why I suggested that you FORCE the sketch to be the same 'length' as the trajectory curve since that helps to keep it logical.

That being said, there are those who prefer to make the Law Curve Sketch 100 units long and then they can treat the Start and Stop points of the twisted section as a PERCENTAGE of the final length of the sweep. You can make it work anyway that you wish.

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/

 

[vitulin]

you still didnt catch, what I thought...I dont talk about the spine itself...lets imagine, that you have section created by line defined by angle and length...and you want to change the angle and also the length of the section line as it goes along the spine...

Regards
Vit

 

[JohnRBaker]

Can you supply a picture or the start of a model showing what it is that you're looking for?

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/

 

[vitulin]

OK, if you look to the attached file and edit the sketch, there are two driving dimensions...angle and length of the line...I would like to change these two dimensions along the curve with some function...as i said, in proe, you would just do t= 0..1 and l=l*t and alfa = sin t for example...
Regards
Vit

 

[JohnRBaker]

Now I have a better idea of what you're trying to do.

OK, we can do what you want, but not by directly controlling the expressions in the sketch but rather by controlling such aspects of the Sweep feature as Angle (we will use and Forumla Law) and Scale (we will use the 'Perimeter Law' which in this case can be considered the 'Length' of the line).

See the attached model where I've took your model and set the Angle to be equal to the value of the height of a Sine Wave and the scale I've used a cubic function from 54mm to 100mm. Note that from the User Expressions item in the Part Navigator, you can control the 'Amplitude' of the Sine Wave and the 'Period' (no of cycles). You can also edit the start and end length of the line as well.

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/

 

[vitulin]

Thanks John,

can you do the scale when the swept feature has already been created?

 

[JohnRBaker]

You can go in and edit the Scale definition. The default is constant, but you can edit it, like any other aspect of the feature, after the fact.

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/

 

[vitulin]

John,
yes, you can edit it, but I wasnt able to add the scale definition once it had been created without...but no problem..
i have attached the file in nx 4 version...I tried to create expression to control the scale...by adding two equations
t and ft...but the problem is, that the scale is still constant and what is even more strange is, that the line is smaller than the line, that I chose for the swept profile...I would like to be able to control the size of the profile along the curve with equation...for example ft = sin(t)+1...
Thanks
Vit