Sketched datum curve tangencies

Discussion in 'Pro/Engineer & Creo Elements/Pro' started by Alex Sh., Dec 16, 2003.

  1. Alex Sh.

    Alex Sh. Guest

    The part I'm working on has a feature that has an airfoil cross-section
    profile.
    The airfoil has been defined as a bunch of points with X-Y coordinates.
    Since the profile varies along the length of the feature, there are several
    cross-sections positioned along its length with each having its own set of
    points defining the airfoil profile at this cross-section.
    My approach is to create a sketched datum curve at each cross-section using
    the points and then do a blend or a swept blend (of course, I could try to
    create section sketches on the fly, but I feel that having them done
    separately makes my job easier).
    Now, here is the problem: I've tried creating the curves by sketching a
    spline and then editing point coordinates manually. I've also tried reading
    point coordinates in from file. Regardless of the method, there are a couple
    places in the resulting spline where it is somewhat distorted in comparison
    to the expected result.
    The Wildfire Help gives an indication that it is possible to edit tangency
    conditions at the spline nodes (definitely at the endpoints, and some Help
    entries seem to indicate that it is possible to do it with intermediate
    points as well). However, I was not able to find the commands Help advises
    to use.
    For instance, here is one Help article:
    To Modify Tangency Endpoints
    You can modify the tangency of the endpoints of an existing spline.

    1.. Choose Modify > Mod Entity.

    2.. Pick a spline.

    3.. Choose Tangency from the MOD SPLINE menu.

    4.. Pick the start or end point. The system displays the current status of
    the point (tangent or non-tangent).

    5.. The system displays the MOD TANG menu, which has the following
    options:

    a.. Add?Add a tangency condition to the selected point.

    b.. Remove?Remove a tangency condition from the selected point.

    6.. To modify another endpoint, pick the other endpoint and choose Add or
    Remove.

    7.. Choose Done Modify to exit the MOD SPLINE menu.


    See Also

    I'd be very grateful if somebody could tell me where these commands are,
    because so far I have not been able to find them. I am using Wildfire
    Foundation, and the Help seems to indicate that these commands should be
    available in the basic package. So far I was able to 'fudge' the splines by
    adding more points, but I'd prefer to do that by adjusting tangencies, if
    possible.
     
    Alex Sh., Dec 16, 2003
    #1
  2. Alex Sh.

    David Janes Guest

    <snip>
    : Now, here is the problem: I've tried creating the curves by sketching a
    : spline and then editing point coordinates manually. I've also tried reading
    : point coordinates in from file. Regardless of the method, there are a couple
    : places in the resulting spline where it is somewhat distorted in comparison
    : to the expected result.
    : The Wildfire Help gives an indication that it is possible to edit tangency
    : conditions at the spline nodes (definitely at the endpoints, and some Help
    : entries seem to indicate that it is possible to do it with intermediate
    : points as well). However, I was not able to find the commands Help advises
    : to use.

    I can't get into correcting Pro/e's help system. If I were to do that, I'd have to
    start with scrapping the whole thing, making it a genuine Windows GUI interface,
    compiled for Windows (see SolidWorks, Pro/DESKTOP) and skipping the typical
    goofiness.

    As for the sketched spline, skip the antiquated help menus. The first thing is to
    get the start and end points coincident, which can be done the usual way, with the
    contraints interface. In fact, in mine, when I make them coincident, I'd swear,
    they're already tangent, even sketching it so that the trailing edge where a sharp
    intersection matters the least, is that start/end edge. While in sketcher, double
    click the spline. They seem to become a closed loop. This will bring up a
    dashboard for spline modification. Pick the 'Control points' radio button to get
    the control poly to adjust the shape of your spline. Also, a big help ~ turn on
    the curve analysis with the icon. It's interactive, updates as you drag the
    control poly, then adjust scale and density to show the shape more accurately.

    David Janes
     
    David Janes, Dec 17, 2003
    #2
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