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Flexible bellows - how to..?

jhiker

jhiker

Alibre Super User
Hi,
The pink part in the assembly is a representation of a flexible stainless steel bellows and I'm happy with the shape of it. The pipe is extruded along a 3D sketch.
I would like to make it look more like the real thing. Ideally I would revolve a single 'bellows' shape at the start of the pipe run and pattern it along the 3D sketch. In two dimensions I can usually cobble something together with linear and circular patterns but in three dimensions that's not applicable.
I can't find a way of doing it - any suggestions?
Pink.png Image 18.png
 
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HaroldL

HaroldL

Alibre Super User
Another feature Alibre could use is Pattern Along Path. Maybe someone could come up with a script to create a pattern to follow the 3D path as long as Python supports it.
 
DavidJ

DavidJ

Administrator
Staff member
Jeff,

Can't you add suitable refence planes/axes to support circular patterns on the curved sections? The curves in your image look to be simple rather than compound, so shouldn't be too tricky to do. Each simple curve must lay in the plane defined by axes of the straight sections on either side of it, then you have to locate the centre of arc (from previous geometry or by measurement/construction). Finally add an axis (plane/point) to use for the pattern.

The straight sections should be easy to pattern.

I'd be tempted to add simple discs and then fillets.
 
jhiker

jhiker

Alibre Super User
DavidJ said:
Jeff,

Can't you add suitable refence planes/axes to support circular patterns on the curved sections? The curves in your image look to be simple rather than compound, so shouldn't be too tricky to do. Each simple curve must lay in the plane defined by axes of the straight sections on either side of it, then you have to locate the centre of arc (from previous geometry or by measurement/construction). Finally add an axis (plane/point) to use for the pattern.

The straight sections should be easy to pattern.

I'd be tempted to add simple discs and then fillets.
Click to expand...
This may be the way. It's long-winded but there doesn't seem to be a better alternative until we can 'pattern along path'. And I don't have Moi3D.
 
DavidJ

DavidJ

Administrator
Staff member
Not that long winded once you've done it once. This is 'posed', but the image shows how to add an axis at the centre of an unknown pipe arc.

Clipboard01.jpg

  1. Add axes to the straight pipe sections.
  2. Use axes from step 1 to define a plane.
  3. Sketch on plane from step 2 - project to sketch the edges of where straight sections meet curved.
  4. Use Intersection tool to find centre of arc, Insert a 3D Point in the sketch (so you can see it outside sketch).
  5. Exit sketch, insert axis using Plane from step 2 and point from Step 4.
  6. You now have an axis that can be used to base your circular pattern around for the 'ribs'.
 
A

AlexB

Member
DavidJ said:
Not that long winded once you've done it once. This is 'posed', but the image shows how to add an axis at the centre of an unknown pipe arc.

View attachment 33993

  1. Add axes to the straight pipe sections.
  2. Use axes from step 1 to define a plane.
  3. Sketch on plane from step 2 - project to sketch the edges of where straight sections meet curved.
  4. Use Intersection tool to find centre of arc, Insert a 3D Point in the sketch (so you can see it outside sketch).
  5. Exit sketch, insert axis using Plane from step 2 and point from Step 4.
  6. You now have an axis that can be used to base your circular pattern around for the 'ribs'.
Click to expand...
Am I missing something here? Can't you just click on the bend portion and then click on insert axis, to insert the bend axis? That's how I do it, or are you doing something more complex?
 
DavidJ

DavidJ

Administrator
Staff member
AlexB said:
Am I missing something here? Can't you just click on the bend portion and then click on insert axis, to insert the bend axis? That's how I do it, or are you doing something more complex?
Click to expand...

That is an even better/faster way to do it ! - I never even thought to try that. (embarrassed smiley).
 
B

browning.9mm

Member
DavidJ said:
Jeff,

Can't you add suitable refence planes/axes to support circular patterns on the curved sections? The curves in your image look to be simple rather than compound, so shouldn't be too tricky to do. Each simple curve must lay in the plane defined by axes of the straight sections on either side of it, then you have to locate the centre of arc (from previous geometry or by measurement/construction). Finally add an axis (plane/point) to use for the pattern.

The straight sections should be easy to pattern.

I'd be tempted to add simple discs and then fillets.
Click to expand...


David:

I was always more of a throw a texture on the part sorta guy.
So as if you have a 5000 part assembly your computer wont take 15 hours to render it or move it.
you can always show more detail in a part view :)

Alex the Red
 
bigseb

bigseb

Alibre Super User
And once again, the above model ends up highlighting a VERY SERIOUS PROBLEM with AD: it's inability to handle anything but very basic imported shapes.

I am unable to save this file. Created in Moi V4 and exported both as stp and 3dm. AD can open but it cannot save. Crashes AD everytime. Seeing how AD is struggling with saving this I am surprised it even opened it.

The file is a solid in Moi, in AD however a check part revealed a lot of errors.

Capture5.JPG

Now this has become a common thing with AD. And yes, I have been complaining about this for years. I used to think it was a bad export from whatever software (and that is still the case with Catia) but I have also gone over many other files and AD just cannot import files correctly. This has to do with the 'general fragility of Alibre Design' that I maintain has been building up over the years.

Moi says the file is a solid and a check within Moi reveals no errors. Yet Alibre shows so many errors... probably why it can't save the file.

What does all this mean wrt the OP? Alibre Design won't allow you to create complex shapes (and I don't think it was ever meant to, would be cool though) but it also won't allow to import these shapes created elsewhere. Hmmmm...

I really want AD to nail this because I like the software and the people behind it are a great bunch. But stuff like this and the other increasing issues make easy to just stick to Moi.
 
HaroldL

HaroldL

Alibre Super User
As much as I like Alibre whenever I see examples like this I get a little bit more disappointed with Alibre's limitations. Not so much that it cannot create these features but that it seems like it never will and there is no indication that there is a plan to add them to the tool set. :(:( But then we don't know what Development has up its sleeve for the next update/version. My recent experience with SolidWorks has shown me that there can be a lot of functionality added to the tool set we now enjoy in Alibre but if it can be added is the question. Twist along path is one example. Adding control nodes to the spline so you can control tangency and curvature is another. Could it be a limitation of the modeling kernel?

But just fixing the bugs and issues that have already been submitted would be good also.

This may be a bit off topic but I see over on Linked In a lot of posts by SolidWorks/Dassault and SolidWorks users showing their "creations". I think it may be students from various engineering programs showing what they are capable of as a sort of resume since there is a lot of job posting there. Funny that I don't see Alibre making a showing there. I found an Alibre page but no updates like Facebook. I can only wonder why.
 
jhiker

jhiker

Alibre Super User
I've tried both approaches - applying a texture to a 3D 'pipe' and modelling a feature on a 2D sketch (radius + straight lines) to produce an elbow.
At a distance the texture kind of looks OK but, as expected, the modelled part is much nicer.
Comparison.png
 
HaroldL

HaroldL

Alibre Super User
To get a better result in KeyShot you should use Displacement on your Bump.
You'd need a better bump map and more time to set it up than I used in this quick example.

RibbedTube.png
 
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