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Fairing splines and making tangent lines

15 REPLIES 15
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Message 1 of 16
Mech.Mon
3425 Views, 15 Replies

Fairing splines and making tangent lines

All,

In other softwares when you creat a spline you are able to adjust the curvature between points by dragging the slope handles at a node. In my file, I have thus far been unable to fair my splines with any kind of consistancy. Also, it should be possible to place a tangent constaint to a straight line at a point, yet I haven't been able to do that either. According to the help files this should be an easy thing to adjust, Why am I not able to?

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15 REPLIES 15
Message 2 of 16
rdyson
in reply to: Mech.Mon

Edit sketch, RMB on the spline - Activate Handle.
Is that not what you expect?


PDSU 2016
Message 3 of 16
Mech.Mon
in reply to: rdyson

I can activate the handle, but not adjust it. Nothing happens when I try.
Message 4 of 16
JDMather
in reply to: Mech.Mon

I was able to add Tangent and dimension (weight) handles and angle, but not able to drag.

I have never seen  this problem before.

 

I started a new sketch in your file and it worked fine.  Not sure what is causing the problem with Sketch1.

 

I'm going to suggest that you break up your Sketch1 into several sketches.

 

On sketch for your grid (and use equal(=) constraint or Pattern for all those 30 dimensions and any other repeating dimensions).

 

Create new sketch for each spine and Project Geometry from Sketch1 only those points/lines you need for each spline.

 

I routinely have multiple splines in one sketch, but something you have done seems to have locked up some of the usual functionality.  It might be best to keep the sketches as simple as possible.


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Message 5 of 16
rdyson
in reply to: Mech.Mon

I suggest drawing only one spline per sketch. If you need them all in one sketch, then when you are happy with them all, create a new sketch and project each spline to it.


PDSU 2016
Message 6 of 16
tsreagan
in reply to: rdyson

If you spline is touching the line that you want the "tangent at point" constraint on,  then you may be able to combine a point constraint and a tangent one.

 

TS

Message 7 of 16
johnsonshiue
in reply to: Mech.Mon

Hi! It is not intuitive when the degree of freedom is available but the handle cannot be dragged. Even though dragging is not allowed, you can still dimension it (angle and magnitude).

I cannot say it for sure if the behavior is to stablize the fit-point spline.The spline is partially constrained. I suspect it is because dragging the handle could deform the spline in a restricted manner, which could violate certain assumptions during the drag.

Thanks!

 



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 8 of 16
JDMather
in reply to: johnsonshiue


@johnsonshiue wrote:

...I cannot say it for sure if the behavior is to stablize the fit-point spline.The spline is partially constrained....Thanks!

 


It doesn't look to be any different than splines I am normally able to manipulate by dragging handle ends. (constrained fit points)


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Message 9 of 16
rdyson
in reply to: johnsonshiue

Interesting, you can manipulate the handles using dimensions even though dragging doesn't work.

 

Image1.png



PDSU 2016
Message 10 of 16
johnsonshiue
in reply to: JDMather

Hi! Indeed, a simple partially constrained fit-point spline may not look too different from Mech.Mon's spline. However, The key difference is the way the constraints were applied. Look at Mech.Mon's spline. If you delete the horizontal construction line and the horizontal dimension 7.250, then the handle will be draggable. Unless there is a bug somewhere (it is not impossible), the behavior shows that the construction line and the dimension somehow reduce the degree of freedom allowing dragging to be successful.

Thanks!

 



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 11 of 16
Mech.Mon
in reply to: rdyson

When I tried to dimension the handle, then change the angle, Inventor crashed.

I tried again and was sucessful. I hate the way it clutters up the sketch until I inactivate the handle.

At least then I can draw a line perpendicular to the handle!

 

It works, thank you.

 

Mon

Message 12 of 16
rdyson
in reply to: Mech.Mon

One of the main reasons for multiple, simpler sketches


PDSU 2016
Message 13 of 16
brucuro
in reply to: rdyson

AUTODESK! is time to review this!!

I found a way, after much much time, and the ideia came to me while i read the comments before.

what i do:
1- create a interpolation spline
2- Select node point and activate handles and curvature
3- constrain handle to be parallel to your line

4- constrain the node point to a point of line to be tangent

(in curves i don't know yet)

Message 14 of 16
JDMather
in reply to: brucuro

I don't understand your response to this old thread.

 

The original problem seemed to be specific to one particular spline - not the usual behavior of splines.

Are you experiencing the same problem?

 

What needs to be reviewed?

Can you post example?


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Message 15 of 16
brucuro
in reply to: JDMather

I may understand wrong the problem...
I find the solution for my case.
In drawing i want that spline stays tangent to other lines and figures. first i was drawing and i try to constrain a spline or a node in spline with the other lines, but that doesn't work. so i searched how to make that, didn't find the answers but reading this post make me light.
i do with the way i describe and i think now they are tangent, at least the logic and the view seems to be the case.
what i think autodesk need to review is the spline itself, i would love to draw splines like vectorial programs and after that add some nodes to constrain and that's should be perfect to me.

 

im sorry if i misunderstand the subjet.

Message 16 of 16
JDMather
in reply to: brucuro


@brucuro wrote:

....
In drawing i want that spline stays tangent to other lines and figures. first i was drawing and i try to constrain a spline or a node in spline with the other lines, but that doesn't work.....


I recommend that you attach your example here (in a new thread) and you might get some alternative techniques.


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