NX 8.5 spline though point (from file) 1

[thekid1]

In older versions I used Insert -> Curve -> Studio Spline -> Through Points.
As this function is being retired what is the best way to create a spline from a points file?

Thanks!

 

[cowski]

As an alternative, you can import your points (File -> import -> Points from file) then use the studio spline to create a spline through points, or if you just want to fit a spline through the points (not necessarily pass through each point) use the new Fit Curve command.

The old spline command isn't retired yet, so you may want to make use of it while you still can...

www.nxjournaling.com

 

[Hamburglar53]

I assume you mean that you used to use Insert->Curve->Spline, since Studio Spline never gave you the option of Points From a File.

I hadn't noticed that the old Spline tool was missing in NX8.5 (unless you use the Command Finder). Yikes! I prefer Fit Splines but a lot of users here use the Through Points - Points From File functionality.

 

[Hamburglar53]

I just spotted that the new Fit Curve tool (in place of Fit Spline) doesn't allow for Points From File either. That's a real pain. Sure you can create the points first using the new Import Points tool, but point selection via the GUI is no easy task and is begging for user error.

 

[JohnRBaker]

Note that we have provided the...

File -> import -> Points from File...

...as more of a 'utility' type function for several reasons.

First off, people have been asking for a straight-forward way of creating points, for whatever use, in NX from 3D coordinates read from any of several different common data formats and so that was the original motivation for this project. However, at the same time we were working on updating/replacing several Curve and Surface creation functions, some of whom had provided for in the past an option to create/edit a Curve or Surface using 'Points from File', and so it was decided that rather than duplicate this 'file import utility' by imbedding it inside of several new dialogs we just left it out, period. After all, these new Curve and Surface functions were already going to have the ability to select points so why not just select the ones which had already been imported by the usage of a common 'utility'?

BTW, you may not have noticed but when you import points using the new file-based function, they are created as a named group (with the name of the data file as the group name) and so this makes it very easy to select ONLY the points which were imported in the first place. Also something else that some of you may not be aware of, while you're in a dialog, like the new 'Fit Curve' and 'Fit Surface', it's very easy to 'select', and later-on to 'deselect', these groups of points via the Part Navigator where groups are accessible from the 'Group' node. And this is of particular interest when it comes time to edit some curve or surface by replacing one set of imported points with another. Since these are now imported as groups and since the Curves and Surfaces created using these new 'Fit' functions can now be done so that they are 'associative' to the points, it's very easy, IF THE POINTS ARE ALREADY IN THE PART FILE AS SEPARATE GROUPS, to swap one group for another during an edit operation. Now try designing a workflow sequence, and subsequent interface to support that, which would allow you to easily do this if you had to depend on importing the points using an option INSIDE of the Fit Curve/Surface dialog itself. After all, if I'm already going to have a 'Select Points' option when creating these Curves and Surfaces, why not just make that the common way to work, period? I ask, what could be simpler?

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[Hamburglar53]

John,
I had tried selecting Smart Points in a Feature Group in the Part Navigator (created using our in house Import Points tool) and was frustrated when I wasn't able to select points from the Part Navigator. I hadn't realized the points created with your new Import Points tool were grouped or that the group could be used for point selection. That is definitely a big help--for a Fit Spline.

What about Through Points splines? That approach doesn't seem to work with the Studio Spline tool. The only way I've found of selecting point data for a Through Points spline is to pick each point one by one.

 

[JohnRBaker]

If what you're looking for is the ability to create a Spline which will pass THROUGH the points (within a specified tolerance) try using the 'Fit Curve' with the 'Source' set to 'Infer' and the 'Method' set to 'Degree and Tolerance'. Note that depending on how 'smooth' the imported points are, you may have to 'play' with the 'Degree' of the spline to get something which falls within the specified 'Tolerance' (you'll get warnings if the result will be 'out-of-tolerance'). Now this should result in a Spline which will be the same basic shape as IF the specified points were what you had used to create a 'Studio Spline' of the same Degree. Granted, internally the points specified, in this case from the points which were imported, will NOT be recognized as 'Defining Points' of the spline for such downstream operations as creating a 'Point Set' or some other function which depends on 'Defining Points' versus Knot Points or Poles. Now as for creating a Spline by Poles, you're correct, 'Fit Curve' does not support that particular scheme nor even anything close, but I suspect that creating a 'spline by poles' using external data is a very rare occurrence.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[Hamburglar53]

1. Yes, I did mean "Through Points Spline". I much prefer using Fit Spline because I don't like the high order/high segment spline that results from Through Points, but I do have users that insist on using them. I hadn't considered the option of using the Fit Curve tool and cranking down the tolerance instead of using Through Points. I'll pass that along and see if it meets their needs.

2. WRT the Fit Curve tool, is there a reason you can't select Smart Points from the Part Navigator?

3. WRT the Fit Curve tool, I've been running some tests to compare the resulting spline from the new tool with the resulting spline from the old tool, and I'm seeing some less desirable splines come out of the new tool. Please see the attached for a comparison of the two resulting splines. I've also attached the point data I used.
4. @thekid: Sorry I hijacked your thread. I hope your question is being adequately answered.

 

[Hamburglar53]

Oops: The comparison .png in the above post should state:
Both splines created by specifying Order: 5, Tolerance: 0.0005”
instead of
Both splines created by specifying Segments: 5, Tolerance: 0.0005”

 

[Hamburglar53]

Aw crud. Double oops. Use this attached point data instead. I like Notepad++ a lot, but the Ctrl+T shortcut to switch rows frequently gets me in trouble. I wish there were a way to edit or delete posts...