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2D Helix

Discussion in 'Using Alibre Design' started by DBC, Aug 15, 2019.

  1. DBC

    DBC Senior Member

    Alibre doesn't seem to have the capability of creating a 2D helix/spiral. Is that the case?

    I am trying create the centrifugal pump I just created in TurboCAD in Alibre to see if can do it there. I start with a helix that will be used for a sweep path, but Alibre's helix tool doesn't seem to allow for a 0 height construct. Am I missing something?
     

    Attached Files:

  2. HaroldL

    HaroldL Alibre Super User

    It's an option from the drop down for the Settings:
    Spiral.png
     
    NateLiqGrav likes this.
  3. NateLiqGrav

    NateLiqGrav Alibre Super User

    Just to be clear the Helical Boss tool make a helical feature from a profile sketch but does not create a helical sketch. However if you want it as a sketch simply make a small square profile sketch and create the helical spiral feature and then project the edge of the feature to a sketch.

    Here is a video on the tool.
     
  4. HaroldL

    HaroldL Alibre Super User

    Bingo!
    I thought I'd just drop a hint and that there wouldn't have to be a step-by-step explanation for this.
     
    Last edited: Aug 16, 2019
  5. DBC

    DBC Senior Member

    Thanks for your replies, but this does not give me what I need. The tool seems to be simply too primitive to give me what I need. I didn't want to have to import a sketch from a different program but that seems to be what is required,
     
  6. simonb65

    simonb65 Alibre Super User

    Following this thread and the helix tool is there to create the path. You still need a sketch for the shape you are going to extrude/cut along that path! If your not wanting to use a sketch ... how do you expect it to work?

    For your example, that sketch would be the outer tubular cross section of the pump.

    How does TurboCAD achieve it? If it creates a sketch for the helix, what does it then do to create the solid from that? It sounds like it is just a case of aproaching the problem from a different angle to one your used to.

    EDIT: Just seen your tutorial preview and it looks like the issue or limitation in Alibre might be to do a tapered profile along a helical path! I'm sure someone will have a solution to that!
     
    Last edited: Aug 17, 2019 at 3:05 AM
  7. DavidJ

    DavidJ Alibre Super User Staff Member

    drafted spiral.jpg

    Sweep with draft (and tidy the end up).
     
    simonb65 likes this.
  8. DBC

    DBC Senior Member

    Can you show how you achieved that, the initial path?
     
  9. DavidJ

    DavidJ Alibre Super User Staff Member

    I used the methods suggested earlier in this thread, projected an edge from a spiral extrusion and used that as sweep path.

    Attached part made in build 20055 - it's only a 'lash up' to show the approach.
     

    Attached Files:

  10. DBC

    DBC Senior Member

    Thanks for the "hints". I still think this is way to convoluted for a process that should take 15 seconds or less to get exactly what one wants (the initial spiral). The gymnastics required with the method hinted at here makes it unworthy of a CAD program in my opinion. Yes, I realize Alibre is its own program and is good in its own class, but I still find that is missing a lot of functions one would expect it to have. I am also confident that now it is operated by Max and the former employees it has a better chance of growing and maturing and that is partly why I invested in it.

    Here is a hint for you longtime forum posters. Keep in mind that new users who ask for help would typically like fuller answers to their questions since they are not as familiar with the program as you are. You seem to forget what it is like to be a new user and often expect them to read your minds. Sorry if this sounds like a rant, and perhaps it is a bit of one. At any rate, thanks for taking time to answer.
     
  11. DBC

    DBC Senior Member

    Here is another problem with the hinted at method. When you project the sketch it become a spline and you cannot trim it as it will only trim the whole spline out or the other objects. It doesn't recognize the tangential intersections.
     

    Attached Files:

  12. simonb65

    simonb65 Alibre Super User

    @DBC , So how does TurboCAD achieve it? ... what is the feature, function or workflow that is missing, that Alibre could benefit from??
     
  13. DavidJ

    DavidJ Alibre Super User Staff Member

    The part file can be 'played back' one step at a time, by moving the 'dog bone' in the Design Explorer (admittedly in this case you have to manually un-suppress to see the helical feature).

    I don't claim the method is perfect. It's a lot easier if you don't try to do everything in one sketch - instead split the geometry into simpler items that can be modelled as individual features. You'll note that I 'trimmed' the final extrusion rather than the sketch - I could have then added a bend as a new feature by using a revolve for example.

    I could have adjusted the initial helical feature 'number of turns' to alter the end point of the spiral.

    By all means suggest new features - but don't expect Alibre to work exactly as another package you are used to does (TC is a rather different beast).

    You can always ask for more detail of a method. Please remember that almost all here are posting out of goodwill in their own time - sounding off isn't likely to elicit more offers of help (or make people want to take the extra time to annotate multiple screenshots with a blow by blow how-to).

    It sounds much more positive if you say "I'm used to tackling it this way (give detail), but don't see that option in Alibre. How can I achieve the same results?" You'll probably get 3 different suggestions for ways to model the item, and some interesting discussion about whether your 'missing function' should be a priority for adding to Alibre.
     
  14. DBC

    DBC Senior Member

    I totally get what you are saying and usually operate on that premise. I just don't make a very good newbie. :). It is like having to learn how to ride a bike again after having a stroke. Not so much fun. :)
     
  15. DBC

    DBC Senior Member

    Hi Simon,

    In TurboCAD just create the helix (spiral) (zero height) and add to the sketch to get the desired path. Tangent arc, etc. See image 1 for TurboCAD. Then sweep with appropriate draft. See image 2
     

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  16. simonb65

    simonb65 Alibre Super User

    Thanks, so it just needs Alibre to be able to treat the helix generated path as an editable sketch object that can have other sketch items appended to it to make a compound path.
    The way most use the helix in Alibre is to produce a helical feature and then 'extend' it by projecting off the end faces and adding additional geometry, but of course in this example, you can't 'easily' maintain that progressive draft this way.
    Would be a nice enhancement for Alibre.
     
    DBC likes this.
  17. DBC

    DBC Senior Member

    I gave this a whirl in SolidWorks since my seat seems to be still active. In SW one could convert the helix into a spline and add the additional sketch components. SW does not have the ability to sweep with draft angle, so I had to loft, but that was very easy. So just as Simon says, Alibre needs to be able to treat the helix generated path as an editable sketch object that can have other sketch items appended to it to make a compound path or allow the helix to be converted to a spline that can then edited and tweaked as needed.
     

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    simonb65 likes this.
  18. DBC

    DBC Senior Member

    I tried this in MoI as well, and it was pretty easy to do in there, both to create the path and to sweep.

    Curious if MoI is still packaged with Alibre. If my memory serves me, I think that it was at one point in time. I have it, but rarely use it.
     

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  19. idslk

    idslk Alibre Super User

    Hello Don,

    here is a little AlibreScript...
    It is not "fully loaded" and it captures not all exceptions, it is only to show that a lot of things are possible with scripting.
    upload_2019-8-18_20-51-25.png upload_2019-8-18_20-58-30.png

    You can fit it for your needs. If you have questions, don't hesitate...

    Regards
    Stefan
     

    Attached Files:

    ajayre and cadtec like this.
  20. simonb65

    simonb65 Alibre Super User

    There is a lot of good features, plus ease of use features (particularly 3D splines and lofts), in MOI that Albire Design would really benefit from. It has been said numerous times by a few of us on this forum. But we still wait and hope!

    Unfortunately it's not!
     
    DBC likes this.

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