Möbius Strip: There must be a better way to do this

[Bldt]

I made this Möbius loop by creating a narrow almond-shaped sketch and putting instances of it every 45° along the path of a circle. Each instance was rotated 22.5 degrees further than the previous instance along its own plane. I then used the Loft tool to bridge the gaps. (Although, I discovered on the first pass that I couldn’t connect the eighth sketch to the back of the first. To get around that I created another instance of the first 1/100th of a unit out, and “closed” the loop that way.)

(*!Sorry this is such low quality… It wouldn’t let me upload anything bigger than 10mb)

Initially I’d tried revolving the sketch around an axis, but couldn’t find a way to make it twist reliably/stably along its path (I tried rotating the face on the end of the extrusion at various intervals around its path, but got mixed results, none of them what I was looking for).

That it isn’t actually closed is also a problem. I’d like this to be a completely solid object (I’d also like the way Shapr3D smoothes out the Loft curve across connections to also happen through that final connection, instead of that rather angular current start/stop area).

I’m sure there must be a better way to do this than how I’ve done it here. Any insight you can offer would be greatly appreciated. In fact, I have the sense I’m going to get the ‘Oh come on, that can be done like this!’ response, but I’m a newb, so I have to be able to endure a fair bit of that.

Thanks kindly in advance.

b.

[Gelphyn]

Hi @Bldt Welcome to the Forum,
This attempted to replicate the Profile and Positioning shown in your Video clip.
If you feel it may be helpful I will provide the basic process info to achieve a similar result:

However this does not have a half turn/twist of a Möbius. A similar situation to your experience, the closing Loft would not take place because the Profile is/was unsuitable.
Ending the Loft and leaving a gap is not satisfactory. To close the Loft it is necessary to Loft between the two end Faces and this creates a second Body. Again not a satisfactory result.
This is a very quick, read not very good, Double Twist [NB. THIS THE INCORRECT DESIGN I TRASHED THE WRONG ONE, WILL REPLACE A.S.A.P]:

Happy S3Ding.

[Bldt]

Thanks for the input! I appreciate the time you put into the problem Unfortunately, the Möbius loop is key to the design of the end result. It must contain the 180° twist.

I would super-appreciate any additional solutions y’all could provide.

Thanks, Sapiens~

[jmartin962]

I believe I have solved it. Naturally there should be an option with the loft to complete the loop. But in leu of that… here is how I solved it.

1. Loft your rotated almond shapes as you did before leaving the gap between the last section.
   

   

2. Rotate to the top plan view, and make a rectangle on the ground plane where one edge is aligned with the middle of the Möbius strip.
   

   

3. Rotate 3D and extrude that rectangle up. This should automatically “subtract” the mobius surface above it.
   

   

4. Then from the top view again, select the newly sliced object, select the move and rotate tool. Move the control locus point to the center of the edge where you just made the slice and rotate 180 degrees. You can now combine the half’s.
   

   

I can upload the shaper project if people want it.

[Gelphyn]

@Bldt
Given existing limitations this is the cleanest/nearest I can get.

1. The Profile was replicated at 15º intervals around a Circle longitudinally horizontal to the Plane.
2. The 180º Twist was created by rotating appropriate Profiles by increments of 15º.
3. The Loft ‘start-finish’ position was chosen in anticipation of the inevitable ‘join’ Profile(s).
4. The chosen option was to Copy+Move, by 0.001mm, the Profile opposite to the Twist Centre Profile.
5. An alternative would be to Loft up to the penultimate Profile to create Body 01 then Loft between faces to create Body 02.
6. Cutting out a similar section of the Möbius and attempting to ‘bridge the gap’ was very problematic.

[Victor_Shapr3D]

Hi, thanks for reporting this. Somehow we are not able to reproduce the issue and you did everything correctly as shown on the video.

Please can you send us the workspace at support@shapr3d.com? We will like to further investigate the issue and then get back to you as soon as possible.

[Bldt]

Thanks! I super super grateful for the time you guys have put in to helping me solve this. Forgive how long its taken me to get back to you.

jmartin962, thanks! I’m not certain, but I don’t think that this works as a viable solution, either. Since the Möbius loop isn’t symmetrical in the way you’ve done your double-loop. I‘ve tried doing half the loop and mirroring it, which like my original post gives me a Möbius strip, but again, I simply cannot abide those unsightly seems.

Another unacceptable attempt:

Gelphyn. This is definitely the closest visually to the result I’m looking for. Ultimately, since I’ll be using this object in both an animation and as a 3dprintable obj, I’d still prefer a solution which doesn’t involve creating another profile at the origin.

Seriously, folks: Thanks for your help and time!

Victor, does your reporting that you’re unable to reproduce the issue mean that you were able to close the loop without creating that additional profile?

I’ve sent the workspace to the support address and copied the URL to this thread.

Y’all rock!

[Bldt]

A screenshot of the error I get when trying to bridge the final gap using the Loft tool:

“Unsuitable profile mappings detected.”

[Bldt]

Another point of interest: I can close the shape using the Loft tool if I don’t rotate the profiles, but leave them in the same orientation as the original around the circle’s path.

It also closes properly if I rotate the profiles 360 rather than 180 degrees along the circles’ path.

So the issue has something specific to do with the Möbius loops’ properties of a 180 degree twist…

[tim]

i am new to shapr3d (and in fact new to 3d design) and came across this thread as i’ve been struggling with ‘twisting’ objects that aren’t simple extrusions along a single axis. i found the dialogue above very useful and thought i’d share my own ‘solution’ in case helpful to others. it seems to satisfy a number of the original issues (it is a true mobius strip with a 180 degree twist, it is a single complete object with no gaps or ‘fixes’ to bridge the final gap) and it is also quick and easy.

there may be a small ‘kink’ half way around the band, but it’s not clear to me whether that is an anomaly in the rendering or an actual kink. any feedback / thoughts much appreciated, but the process has definitely helped me understand some important concepts.

1. i created the profile (almond)

2. i revolved the profile 180 around the vertical axis

3. i selected the new ‘end’ shape and rotated it by 90 (at this stage i basically have half a mobius strip)

4. i continued to select the new ‘end’ shape and revolved it another 180 around the vertical axis

5. again, i selected the latest new end and rotated it again by 90

6. i joined the two half mobius strips by union

i experienced similar issues as described in the thread if i tried to do this in one step and rotate the end by 180

[Bldt]

How I solved this, was to construct two Mobius loops the way I had in the post above using the almond shaped slices, use the loft tool to close all but the last gap (attempting to close that last gap always results in an error, for some silly reason). Then removed half of each loop, move them together then ‘union’ them.

This has given me the best result with the least visible kink. It might get even better if I created another 8 almond slices in between the others to give the loft tool even more points to curve through and keep the gaps even further from the eventual seem.

[Bldt]

Any update from the gurus?