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# Modeling a Twisted Ribbon

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SEANT
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Post Options    Thanks(0)    Quote  Reply Posted: 13.Oct.2018 at 11:43
 philippe JOSEPH wrote:Seant you are number "ONE", tell us more !!!!!!!!!!!!Eventually a "step by step" drawing ?I suppose that LOFT is like Kent's method : LOFT between 2 concentric helixes, and then ...I suppose that THICKEN is what Kent what waiting for or his next step.

That's correct.

I think the "Step by Step" would best be done by each individual.  I can tell you it's possible, you tell me what your specific steps were.  Experimenting is where we find the capabilities, and limitations, of AutoCAD.
John Connor
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Post Options    Thanks(0)    Quote  Reply Posted: 13.Oct.2018 at 13:55
Very nicely done and explained SEANT.
"Humans have a strength that cannot be measured. This is John Connor. If you are reading this, you are the resistance."

philippe JOSEPH
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Post Options    Thanks(0)    Quote  Reply Posted: 15.Oct.2018 at 07:43
HOC ERAT IN VOTIS, but different.

Edited by philippe JOSEPH - 15.Oct.2018 at 08:02
SEANT
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Post Options    Thanks(0)    Quote  Reply Posted: 15.Oct.2018 at 10:38
Nicely done.
philippe JOSEPH
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Post Options    Thanks(0)    Quote  Reply Posted: 15.Oct.2018 at 12:41
Thanks Sean but I have to work the model to make it look much more like the very first image and also I have simplified the SUBTRACTed notches with a "simple" EXTRUDE of a region along a path like a thread that we can see for example on your image.
Kent Cooper
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Post Options    Thanks(0)    Quote  Reply Posted: 16.Oct.2018 at 20:41
 philippe JOSEPH wrote:...I suppose that THICKEN is what Kent what waiting for or his next step.

Yes, it is [a newer command than the version of AutoCAD I used for years, so I wasn't aware of it].  BUT if the small difference matters, THICKEN goes only one way from a Surface, with no center-the-thickness option -- it's not like giving a Polyline width [which is centered].  So if the thickness of the ribbon needs to be centered across the zero-thickness twisting Surface, I think it's necessary to LOFT from one Helix to the other, and also LOFT in the other order [from the other to the one], and THICKEN both of the Surfaces by half the desired total thickness, then UNION the two Solid results together [and Erase the Surfaces if you like, if DELOBJ wasn't set to do that in the process of Thickening].
philippe JOSEPH
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Post Options    Thanks(0)    Quote  Reply Posted: 17.Oct.2018 at 07:13
I have placed my AutoCAD file : Modeling a Twisted Ribbon-01.dwg here in the CAD/BIM Blocks library.
SEANT
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Post Options    Thanks(0)    Quote  Reply Posted: 18.Oct.2018 at 09:53
Very nice model, and excellent tutorial.

I see now that your earlier request to me was an opportunity/offer to create the tutorial.  This may be a little late but, Thank you.

I'll see if some time presents itself - perhaps I can put something together that has something new to offer.
SEANT
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Post Options    Thanks(0)    Quote  Reply Posted: 18.Oct.2018 at 09:58
Kent Cooper wrote:

 philippe JOSEPH wrote:...I suppose that THICKEN is what Kent what waiting for or his next step.

Yes, it is [a newer command than the version of AutoCAD I used for years, so I wasn't aware of it].  BUT if the small difference matters, THICKEN goes only one way from a Surface, with no center-the-thickness option -- it's not like giving a Polyline width [which is centered].  So if the thickness of the ribbon needs to be centered across the zero-thickness twisting Surface, I think it's necessary to LOFT from one Helix to the other, and also LOFT in the other order [from the other to the one], and THICKEN both of the Surfaces by half the desired total thickness, then UNION the two Solid results together [and Erase the Surfaces if you like, if DELOBJ wasn't set to do that in the process of Thickening].

Good point.  If I do find the time to create a version of a tutorial, I'll keep accuracy in mind.
SEANT
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Post Options    Thanks(0)    Quote  Reply Posted: 18.Oct.2018 at 10:09
I suppose keeping a mind towards accuracy requires hard parameters.  The OP (Arunvigneshram) had a picture, and a description of a strip of metal inserted into a pipe.  A new tutorial should make use of philippe's dimensions - a 20 mm inside diameter pipe @ 180 mm long with a .2 mm thick strip with one twist.

I'll see what I can do.

Edited by SEANT - 18.Oct.2018 at 10:17