3D spline

Discussion in 'Pro/Engineer & Creo Elements/Pro' started by Peter, Nov 8, 2006.

  1. Peter

    Peter Guest

    I'm trying to model a hose that curves through 3 dimensions. In the
    past, I have created a sweep, using the blue spline as the trajectory
    but this only produces flat (2 dimensional) curves.
    I created some points at varying X,Y and Z positions and through these
    points, I made a datum curve that was close enough to what I wanted.
    But the sweep won't recognize the datum curve as a trajectory.
    Can someone help me with this or point me to a tutorial on how to do
    this?
    Thanks. Peter
     
    Peter, Nov 8, 2006
    #1
  2. Peter

    Peter Guest

    I forgot to say that I am using WF2.
     
    Peter, Nov 8, 2006
    #2
  3. Peter

    David Janes Guest

    The Sweep feature won't follow a spline. You could do it with straight
    sections, single or multiple radiuses. If all you really need is to make a
    circle follow the spline, use 'Insert>Advanced>Pipe'. You can specify solid
    or hollow, OD and wall thickness. It kinda looks like a hose.

    David Janes
     
    David Janes, Nov 8, 2006
    #3
  4. Peter

    kenny Guest

    You cannot sweep along a spline.
    Choose the best two views that describe the path and draw curves on
    planes, make sure that the ends are coincident and that the curves do
    not self intersect. Create a curve by intersecting these two and you'll
    be able to sweep along it. If your run is complicated you may have to
    make it in several parts.
     
    kenny, Nov 9, 2006
    #4
  5. Can't try this on WF2 as I'm on WF3 but...

    Some thoughts;

    Are you using Insert > Sweep? I think using VSS will allow you to use curve
    thru points. [I'm led to believe this should be the default function now for
    a constant section sweep - unless you have nontangent chain or want to use
    the fill option]

    Have you got ISDX? A 'free' Style curve through your points should also be
    recognised

    Create a surface using the curve as a boundary and then use the surface edge
    as your traj?

    WF3 will use a curve thru points as a traj on a insert > sweep


    Sean
     
    Sean Kerslake, Nov 9, 2006
    #5
  6. Peter

    John Wade Guest

    Whilst you can't sweep along a spline, (splines don't have orientation)
    you can create a multi-trajectory sweep along 2 splines, so if you
    create a second spline parallel to the first, you can make the feature
    as you describe it.

    Hence, whilst 'pipe' will effectively make a rond section sweep along
    a spline, if you want other shapes you'll then need to extrude a
    surface through the pipe centreline, and use it's intersection with the
    pipe as your second trajectory.
     
    John Wade, Nov 9, 2006
    #6
  7. Peter

    David Janes Guest

    Good question, Peter; lot's of good ideas guys. One of the suggestions, the
    VSS still puzzles me. It's not that it's not possible. It just seemed, when
    I first thought about it, that there's no good way to create the second
    trajectory curve so that it controls the section size and shape as intended
    and without kinking or selfintersecting. And we are talking about a 3d curve
    that can wiggle all over the place, changing directions repeatedly, even
    doubling back on itself. So a simple copy/offset wouldn't do. Any ideas? If
    you can do it, I'd like to see it.

    David Janes
     
    David Janes, Nov 9, 2006
    #7
  8. Peter

    John Wade Guest

    Hi David,
    You can make the second curve, but the only way I know is to create a
    pipe along the initial spline (which technically you aren't doing, but
    if you put it through the same points with the same constraints the
    centreline should be the same ) then extruding a surface through the
    pipe, with the centre spline as sketch, intersecting the pipe surfaces
    and the extruded surfaces to get a second curve offset from the first
    by the radius of the pipe, cutting out the pipe, and using the two
    trajectories left.

    I have only done this once, looked at the resulting model, thought
    'what a mess, my intended section is more or less perpendicular to a
    plane anyway, I'll let that drive the direction and accept the model
    isn't perfect'
     
    John Wade, Nov 9, 2006
    #8
  9. Maybe I've missed something in the discussion but you don't have to have two
    trajectory in the VSS function, surely Peter only wants one traj?

    Theres also an Option on the Dashboard - Constant Section Sweep


    Sean
     
    Sean Kerslake, Nov 9, 2006
    #9
  10. Peter

    Jeff Howard Guest

    Additionally, unless there's something driving d(radius) it remains constant.
    (The Constant Section option is interesting, allows the use of additional
    trajectories that create conflicting or unsolvable constraint(?) and allows the
    use of projected section curves.)

    - - - - -

    Wondering about the difference in users' perceptions re sweep functions; is VSS
    relatively new to Foundation? Perhaps it's because I'm a newcomer to Pro/E
    (started with WF), but seems to me that VSS is the 'one size fits all' sweep
    function, the rest (older?) serve occasional or 'special purpose' needs. I've
    gotten the impression from some older users that they think VSS is "over kill",
    etc. and it's puzzled me.

    ================================
     
    Jeff Howard, Nov 9, 2006
    #10
  11. Peter

    David Janes Guest

    I guess, Sean, that you know a good bit more about the VSS in WF2 than I do.
    Thanks for the tip. And, yeah, works very cool. Well... oh, no, not in WF2
    (or at least I can't confirm). I did it in the only thing I have available
    for messin' around ~ the SE of WF3. So, it works great there.

    Come to think about it, this doesn't accomplish anything beyond the Pipe
    feature, if one wishes to do only a round hose. You can, with the new VSS,
    create any shape to sweep and with only the central 'trajectory'. Well, I
    guess I exaggerated: an elipse follows the normals and constraints based on
    the twists in the 'curve thru points' foundation of the section. IOW, Pro/e
    picks the sketch plane and orientation and your elipse WILL follow the
    vertical/horizontal orientation. Or maybe this is where that second
    trajectory comes in, where you want to get beyond the limitations of this
    default orientation. And, Sean, you didn't just do an artful dance around
    how to construct this second 3d section guide trajectory by bringing up the
    single trajectory VSS, did you!?! I'd like to be able to tell that second
    trajectory to twist, but stay equidistant from origin or to stay in a
    normal plane but increase in distance, meaning the section expands. I don't
    know how to do any of these with the resources available.

    David Janes
     
    David Janes, Nov 10, 2006
    #11
  12. Peter

    Jeff Howard Guest

    Part of VSS' beauty is that you don't need the second trajectory. (Or if you
    need one for another function, create it with VSS.)
    Place an angular dimension relative x or y reference. Drive the angle as a
    function of trajpar.
    Drive the dimension as a function of trajpar.

    I think VSS tends to intimidate, sometimes, because if you don't understand how
    it drives section constraints it will be frustrating. Once the lamp starts to
    flicker, though, it becomes apparent it's an incredibly versatile function.
     
    Jeff Howard, Nov 10, 2006
    #12
  13. Peter

    John Wade Guest

    Dammit, so there is. I'll be using that then. That's what comes of
    sleeping in training courses.
     
    John Wade, Nov 10, 2006
    #13
  14. Peter

    kenny Guest

    There is a way to do this with only one trajectory.
    Set up a ribbon on this with as many controls as desired to control the
    X-traj.
     
    kenny, Nov 10, 2006
    #14
  15. Peter

    David Janes Guest

    You get training classes!?! I thought it was just a myth.
     
    David Janes, Nov 10, 2006
    #15
  16. Peter

    John Wade Guest

    I did at Caterpillar, but nowhere else.
     
    John Wade, Nov 10, 2006
    #16
  17. Peter

    skyap Guest

    What you have done is fine - I did this the other day and had the same
    problem. You create a 3d spine as you have done by creating points then
    creating a spline through these points. You can also set the
    tangency/normal at each end to control it a bit more. Then choose
    VARIABLE SECTION SWEEP. Just use the spline you created as a single
    trajectory, sketch your profile in the sketcher that appears and away
    you go!

    Worked for me :)
     
    skyap, Nov 10, 2006
    #17
  18. Peter

    David Janes Guest

    Yeah, sounds familiar. They, as the biggest users of Pro/e on the planet,
    had some respect for it and for what it took to be a proficient user. I was
    there as a contractor, the direct hires got the training. At least they went
    through a tooling apprenticeship program to learn stuff about how a product
    gets made. That was the best thing about Cat. At least I had the tooling
    apprenticeship and the formal training on Pro/e before I got there.
     
    David Janes, Nov 11, 2006
    #18
  19. Peter

    Peter Guest

    It looks like the question that I asked about 3D hose created quite a
    response and although most answers were waaay above my skill level, I
    thank everyone who replied.
    I was getting kinda frustrated and later on in the evening, while
    watching Millionaire, I happened to mention it to the wife (the problem
    not the frustration).
    She said that I should create the points with the "Offset coordinate
    system point tool" option from the datum points flyout, then I can make
    a datum curve through the points and use the curve to create a hose.
    (Where does she pick this stuff up from?)
    "Yea right!" I snorted (trying to save face), "sweep won't recognize a
    datum curve".
    She never even raised her eyes from her knitting but smiled and said
    quietly "Try Variable section sweep". (she must get it from one of
    these Home improvement shows that she is always watching).
    I almost dropped my Guinness. "Could this be possible?" I thought.
    I pushed aside my bag of Ripples and sweeping the crumbs from my shirt
    front, I rushed to check it out.
    And guess what? It worked, exactly as I wanted. Of course, I never told
    her that, but she knew.
    The most difficult part is determining the XYZ positions for the
    points, but after she explained how to get them, it became much more
    semi clear.

    Thanks again to all who replied.
    Peter
     
    Peter, Nov 11, 2006
    #19
  20. Peter

    neonerd Guest

    using the blue spline as the trajectory


    That was a hint, wasn't it?
     
    neonerd, Nov 11, 2006
    #20
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.