Inventor General Discussion

## Inventor General Discussion

Valued Contributor
Posts: 70
Registered: ‎06-21-2013
Message 1 of 5 (480 Views)

# 2D equation curve for a parabolic spiral

480 Views, 4 Replies
06-22-2013 05:19 PM

Can anyone please advise me what the 2D or 3D equation curve for a parabolic spiral, otherwise known as a Fermat's spiral would be?

I have found this info but do not know how to apply it:

Fermat equation

Therefore in terms of the affine plane its equation is

The Fermat curve is non-singular and has genus

I have also found this: $r^{2}=a^{2}\theta$

Please see image attached.

*Expert Elite*
Posts: 26,525
Registered: ‎04-20-2006
Message 2 of 5 (449 Views)

# Re: 2D equation curve for a parabolic spiral

06-23-2013 07:00 AM in reply to: CJ.10E-10mm

Are you familiar with using Equation Curves in general?

A while back I posted some examples that my students submitted.

I think Autodesk employee has also posted some examples.

At one time there were several that were included in the Samples install, there should be a thread here with those attached.

Do a search and come back with more questions if you can't find the examples to help you work it out.

Please mark this response as "Accept as Solution" if it answers your question.
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Valued Contributor
Posts: 70
Registered: ‎06-21-2013
Message 3 of 5 (435 Views)

# Re: 2D equation curve for a parabolic spiral

06-23-2013 09:17 AM in reply to: CJ.10E-10mm

Thank you, I will search later today.

Equation Curves do appear to a novice like some form of 'black art.' So I am wondering if there is a 'user friendly; App that allows one to configure the equation for any given shape in an Excel Spreadsheet?

Thank you once again.

Distinguished Mentor
Posts: 891
Registered: ‎04-11-2005
Message 4 of 5 (426 Views)

# Re: 2D equation curve for a parabolic spiral

06-23-2013 11:09 AM in reply to: CJ.10E-10mm
If you can create x,y,z coordinates in a spreadsheet, IV will import them and draw a spline through them.
Valued Contributor
Posts: 70
Registered: ‎06-21-2013
Message 5 of 5 (408 Views)

# Re: 2D equation curve for a parabolic spiral

06-23-2013 03:11 PM in reply to: rdyson

Thank you Rdyson.

Is there any chance you could assist me with my question on:Variable pitch helical coil with smooth blend please?

Thank you once again.

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