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Equation Driven Curves/Superellipse?

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Message 1 of 11
boyer.ryan29
3382 Views, 10 Replies

Equation Driven Curves/Superellipse?

Is it possible to create an equation driven curve in a sketch?  Specifically, I'm trying to create a superellipse (also called a Lamé Curve).  I know that you can do basic arithmetic while creating regular lines, but I haven't found anything for curves.  Or, if it's not possible, is there a way to get something similar to a superellipse?

 

Thanks,

--Ryan

10 REPLIES 10
Message 2 of 11
etfrench
in reply to: boyer.ryan29

Have you tried using the API?

ETFrench

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Message 3 of 11
sebastianH4EZX
in reply to: etfrench

How does it help using API? Can you use some type of script, and if so, how? 🙂 I would love to create a perfect superellipse.

Message 4 of 11
mbyasar75
in reply to: boyer.ryan29

Hi,

 

For my project I need an "equation driven curve" feature like Solidworks has. My project is about "adjusted epicycloid curves" and their use in manufacturing. Therefore I wrote some codes in Basic language to make the computer create parametric equations and afterwards to make Solidworks draw the curves that I need. When I intented to migrate from Solidworks to Fusion 360 first, I saw that Fusion 360 hasn't got an equivelant feature. So, I modified my codes to produce CVS values and had them read by Fusion (with the help of ImportSplineCSV.py) which was a sucsess, but the spline created by Fusion is sluggish as to mouse moves and to extrude command.

 

I should let you know that I used hundreds of points to have a very precise curve. Because these parametrically generated splines will be the main element of a gearbox which has very tight tolerances.

 

I would like know whether Fusion 360 team will add a dedicated feature for this purpose? I attached some screenshots of my work.

 

Thank you very much.

 

Mehmet.

Message 5 of 11
etfrench
in reply to: mbyasar75

Can you attach a file with one of these curves?  What are the tolerances you require?

ETFrench

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Message 6 of 11
mbyasar75
in reply to: etfrench

I attached the file as you required.

 

The spline in the file is to be multiplied in a circular pattern. Each spline will take place of a gear tooth and each tooth will have a corresponding pin.

 

Maximum distance between the tooth and the corresponding pin must not exceed 0,001 mm. Because there will be some dimensional manufacturing errors during manufacturing processes as well. So, I want to take advantage of the most precise spline available to avoid improper theoritical geometry and machining results. That's why I use lots of points to create the spline.

 

Thank you.

Message 7 of 11
etfrench
in reply to: mbyasar75

I was curious to see if the algorithm used by the mesh tool would give a more accurate curve than the import spline script.  I think you'll find it fits the data better.  Can you compare curves generated in Fusion 360 to the same curve in Solidworks. It would be interesting to see which is better.

 

An added benefit of this method is using fewer control points will also make Fusion 360 more responsive. 

ETFrench

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Message 8 of 11
etfrench
in reply to: etfrench

The screencast didn't attach itself in the previous message.

ETFrench

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Message 9 of 11
mbyasar75
in reply to: etfrench

I am going to send another message about this curve and generation method comparasion in this week.

 

 

Message 10 of 11
MACABItech
in reply to: etfrench

which API?

Message 11 of 11
TrippyLighting
in reply to: MACABItech

Fusion 360 has an API that allows you to write scripts in Python, JavaScript and C++

Peter Doering

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