topic Nautilus spiral shape in Fusion Design, Validate & Document Forum

Nautilus spiral shape

neilvdm — Fri, 28 Feb 2020 06:19:28 GMT

Hey all,

I have been struggling with this for a couple of days and just cannot get it right.

Can anyone with more experience please help?

I have tried with multiple plane on paths, drawing a circle on each one and then using loft, currently Im now at one plane at the beginning and another at the end.
I cannot seam to get the sweet spot to have the edges just touching., either they are too far apart or I get an error that the loft is intersecting itself.
Then also, the start of the loft "dips" very suddenly and when it gets close to the end, the curve becomes blocky.
Fusion 360 file
what I would like to getmy result

Re: Nautilus spiral shape

etfrench — Fri, 28 Feb 2020 08:05:21 GMT

Once you have it close, try Thickening. I don't think it's possible to get it to just touch without a lot of math. You're dealing with a theoretically infinitely thin surface.

Re: Nautilus spiral shape

TheCADWhisperer — Fri, 28 Feb 2020 13:58:00 GMT

This was a very very quick and simple trial - I didn't try to match your parameters or even adjust the Coil to see if I could get close, but this what I would experiment with adjusting Pitch and Taper, starting coil diameter and sketch diameter. Not sure if there is a sweet spot, but I would think that someone has solved this before. A bit of research might be in order.

Re: Nautilus spiral shape

chrisplyler — Fri, 28 Feb 2020 16:09:46 GMT

It still won't be easy, but I would Sweep it instead of Lofting it. At least that way the circular section will remain constant all along the path. You'll have to use a Taper Angle in the Sweep settings, and try to get it to match the angular unwrapping of your path as close as you can.

Re: Nautilus spiral shape

neilvdm — Sat, 29 Feb 2020 07:01:43 GMT

Thanks,
Ill have a look once I have some free time at the office today.
Yes Im certain people have done it, I have been searching to find examples/explanations, but nothing yet that helped me. Thats how I ended up here🙂

Re: Nautilus spiral shape

neilvdm — Sat, 29 Feb 2020 07:03:44 GMT

That might just be the way to approach this 🤔

I most certainly will give it go and let you know.

Thanks!