How to draw a Mobius Curve?

[ianhughes7UFVF]

Hi

I was asked if I could do this in Fusion:

Apparently it is a mobius curve.

To me, I reckon it would be a Sweep with a triangular shape flowing along the Path.

But to create the shape in 3d is the problem. I am used to creating on a single axis but this looks like I need to draw on a 3 axis at once.

Any advice would be appreciated.

Regards

Ian

[wmhazzard]

Here is one way. 

https://www.youtube.com/watch?v=AFzLHNXiwx8

[Anonymous]

I'd like to see his too. I don't think it would be as simple as sweeping a triangle along a closed loop though. It's not three faces, it's one face - follow a face along the curve and after 3 loops you'll end up back at the same point. Maybe a line lofting three times along a closed loop with a 120 degree rotation per loop? If that's even possible...

[Anonymous]

****, opened this to read but didn't post for a few hours so someone beat me to it.

On the bright side, Maker's Muse's video nails it. Use an equilateral triangle with the path in the centre and set the rotation to 120 degrees and it meshes perfectly, without the artifact he had making the strip.

[laughingcreek]

The challenge with using the sweep function is that once you move a point of your path (spline) off the sketch plane, anything sweped along that path will twist.  just putting 180 (or 120 for a triangle, etc) for the twist angle won't give you the desired result.  There are ways to measure the resulting error angle, but in the end I just ended up doing by trial  and error.  The needed angle will change with every edit to the path.  You also can't sweep the entire path.  in the attached i just wen to .999% of the path, and lofted the ends together.

you can also do it with a center line loft.  you can induce twist by changing the white control points while in the loft dialog.

attached is a quick example of each approach, and some pics.

[ianhughes7UFVF]

Hi

I am impressed with what you have done and can see the method of using the sweep to create the shape along the sketch path.

I am stuck back on how to draw the sketch line in 3 dimensions. I am stuck on drawing on either the x y or z axis but don't understand how you got the sketch in 3 dimensions at once?

Sorry to continue my dense career.

Regards

Ian

[laughingcreek]

For something as free form as this, I just use the move tool to move the points around.  Maybe this screen cast helps.

a few thoughts/ideas-

-I didn't demonstrate well here, but when moving 3d points freehand the approach I take is to move 2 dims while looking at a specific view directon(such as x and y  from the top), and changing to an iso view I adjust the third dim (the z)

-you could construct geometry ahead of time to use as a visual scale.

-you can add control points (I think I did that once in the screen cast)

-for this type of thing I will usual keep the tangent handles "natural", meaning they move around of their own with edits.  if you accedently move one, it will turn ctan in color, and doesn't move naturaly an more.  just select it and hit delete to reset it.

-on the other hand, if you need a section to stay on a sketch plane, you can constrain the tangent handle on purpose to make that section flat-ish

[wmhazzard]

Here is a video explaining the basics. 

https://www.youtube.com/watch?v=qGQgMADxoFU&t=377s