studio spline constrain in 2D (NX-9) 1

[ak2711]

how could we constrain studio spline with through points in 2D? What are the best possibilities and could any one explain how to maintain G1 & G2 continuity?

 

[Toost]

If you define the spline outside the sketcher and not as a spline in a sketch, it's pretty straight forward.
If the option "Associative" is on, any points snapped will be associated ( Constrained to, G0)

In NX there is no such thing as 2D, all geometry has x,y and z values. You can create / draw objects / Splines with a constant z.
which is "2D".
When you say "explain how to maintain G1 & G2", - what , how and where ?
- Do not try this on a spline in the sketcher, then i understand the question. Assign it to a Studio Spline which doesn't belong to a sketch.

Regards,
Tomas

 

[ak2711]

PFA dialog box of studio spline with through points, their I have marked the G1 & G2 in the constraints section, if I select G1 or G2, the spline profile will not retain its contour, instead it distorts & it is clueless, if you could tell me usage of those constraints that would be great help
Thank you so much THOMAS for your response,

Regards
Arun Kumar K

 

[Xwheelguy]

G1 is tangent continuity and G2 is curvature continuity. These are indicators of how smoothly 2 curves transition into one another. Curves that have G2 continuity are smoother than curves that have G1 continuity.

The spline is changing shape because when you assign more than G0 (positional continuity), the spline poles must align accordingly, depending upon the continuity you've selected. G0 aligns the first pole (endpoint) of splines with target selection; G1 aligns second pole with target selection; G2 aligns third pole with target selection.

If you do not understand any of this and you're going to be using splines, then I'd strongly suggest you attend some additional training.

Tim Flater
NX Designer
NX 9.0.3.4 Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[Xwheelguy]

I looked at your image after posting my response. Please add this to the above.

You typically don't constrain every point of a spline with a continuity constraint - just the ends. Doing so will increase the segmentation and make the spline extremely complex and "heavy". Again, the details as to why and what's best practice are covered in training for these types of things.

Feel free to search this group, as this has been covered a few times over the years and hasn't changed.

Tim Flater
NX Designer
NX 9.0.3.4 Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[Toost]

Yes, listen to Tim.
You normally only assign G2 at the ends. Or in some odd cases i have matched the curvature at the ends and one intermediate point.

Is the example you provide a test or ?

Regards,
Tomas

 

[ak2711]

Thomas & Tim Thank you very much, Yes Thomas actually I was studying the behaviour as well as comparing the studio spline in 2D(arresting/constant Z direction) with through points as well as By poles,

 

[Xwheelguy]

I feel that if at all possible, it's easier to control the shape of a spline using the By Poles method - Through Points can get a little unpredictable, particularly when assigning constraints afterwards. Much of this depends upon the spline shape.

Tim Flater
NX Designer
NX 9.0.3.4 Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB