How can I create a Möbius Strip?

[ptc-4380682]

I'm really struggling with this issue. Does anyone know how to create a nice, visually pleasing möbius strip in Creo Schools addition? Here is what I really want the model to look like: http://sketchup.google.com/3dwarehouse/details?mid=316a27ba42a11a71abdffc6614cbf81a&prevstart=0 (the model is done in skechup, free from Google, if you are wondering about how to open .skp.

I need all the help I can get, thank you.

[VladimirN]

Some mobius strip/gear models at GrabCAD site: http://grabcad.com/library/tag/mobius

[MikeFitch]

Off hand, I think you could do it with a swept blend on a circular trajectory. Just start and end with a square and move the start point to create the 'twist'.

* You may have to do it in two semicircular sections.

[Patriot_1776]

Variable section sweep would be what I'd use. It would make sure the strip length would remain constant, something that would be tough to do with a swept blend.

Of note, I think I came up with a "new" type, and am looking into whether there is a aplce to submit my model t see if it meets the qualifications. I BELIEVE it does, as I've made a paper model, but we'll see.

[KevinBradberry]

In case Lucas needs a bit more info:

• Make a variable section sweep using a circle as the trajectory.
• Use a rectangle as the shape of the section (or someting more creative after you try this).
  • Allow there to be an angular dimension that will allow the rectangle to rotate.
  • The section should only be constrained to itself. Meaning no dimensions to an axis line (other than the angular dimension) or perpendicular constraints to the axis lines, etc.
• While inside sketcher, create a relation (Tools>Relations) such as sd16=360*trajpar*1. Substitute sd16 with your angular dimension's alias. The 1 after trajpar can be increased to add rotations.

I hope this works for you, let us know.

-Kevin

[Patriot_1776]

Why a rectangle? A mobius "strip" is just that, a surface. Also, only odd increments of 1/2 turns (180deg) make a Mobius Strip (i.e.: 180deg, 540deg, etc.).

[kleipold]

Worked well! I did this as two halves, with the equation twist*trajpar*1/2. Where twist is the number of loops times 180. (I'm a parameter junky.) Using a one sided thicken really shows the one sided-ness well, but a middle thicken will add material fine.

[Patriot_1776]

Kate, can it be done with one VSS (variable section sweep)? Trick question....... If "not", why not?

[KevinBradberry]

Lucas,

By the way, I do not know the definition for Mobius Strip, I only saw a picture. If what Frank says is correct, then adjust accordingly.

Regards,
Kevin

[MikeFitch]

This was done using two swept blends, though I think Frank's solution is probably more elegant.

http://dl.dropbox.com/u/11404499/prt0001.prt.2

Good luck!

[KevinBradberry]

Lucas,

Sorry, I tried to "adjust accordingly" my suggestion and I could not get it to work unless using a multiple of 360.

Frank,

How do you make it work with variable section sweep?

Mike,

Your part looks good!

[Patriot_1776]

Interesting Kevin, this might be a "bug" not allowing a single-sided surface. I'd never tried it before. It might hinder me in making mine......

[Patriot_1776]

Interesting....

[KevinBradberry]

Well...?

How about a .prt file so it can be interesting to others .

[Patriot_1776]

Ahhh, that's the rub. I'm going to try it one more time without a technique I developed, and if so, I'll post it. If it can't be created any other way, I'll have to save it for my future business in teaching Pro/E.

....and besides, it's still interesting.

[buddyer]

[Patriot_1776]

Buddy, it looks to me like there's a full 360deg rotation there. If so, it's not actually a Mobius. I true Mobius only does a half twist per revolution, or odd increments of half twists. Can you attach a STEP file please?

Thx.

[buddyer]

Why didn't you upload the PRT.

my english is poor ,i cannot explain clear what is my mean.

this is my prt .(creo 1.0)

[ptc-20197]