Fitting a Curve to Offsets Points in Rhino

Discussion in 'Software' started by CET, Jan 3, 2006.

  1. CET
    Joined: Sep 2005
    Posts: 114
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    Location: Utah

    CET Senior Member

    I am attempting to duplicate a model in Rhino using a table of offsets. I’m having a problem that I’m hoping someone can help me with. I would like to build a curve that fits the offset points. I first place points based on the offsets then build a control point curve, attaching the control points to the offset points, but the curve always falls inside the offsets, so I have to go back and manually edit the control points and try to fit them to the offset points. The problem is that, to create a fair curve, Rhino places the control points in a different location than where I place them when I build the curve, so they are not in alignment with the offset points. I can manually move the control points and reattach them to the offset points, but it usually ends up creating unfair bulges in the curve. Although I realize fitting a curve to offsets will not necessarily result in a particularly fair curve, the bulges I mention definitely do not correspond with the architect’s lines. My question is...is there a way to fit a control point curve to a set of points and have the controls points stay attached to the offset points? Or, is there a better method for fitting a curve to a set of offsets? Thanks in advance for any info.

    CET
     
  2. Raggi_Thor
    Joined: Jan 2004
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    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    I don't have Rhino oon this pc, but there is acommand called something like Curve Through Points. You can find it in the pulldown menu or the toolbar or start typing "Curve" and see what commands you have.
     
  3. Windvang
    Joined: Jan 2006
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    Location: Rotterdam,The Netherlands

    Windvang Yacht Designer

    Try SrfPtGrid command. See Rhino Help for instructions.
     
  4. Jollydog
    Joined: Dec 2005
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    Location: MI, USA

    Jollydog Small Craft Designer

    Make sure that you are using the Interpolate Curve command (_InterpCrv) as opposed to the Control Point Curve (_Curve).
     
  5. CET
    Joined: Sep 2005
    Posts: 114
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    Location: Utah

    CET Senior Member

    Thank you all for the responses. I've tried all three suggestions and they all work great. The 'Fit to Points' and the 'Interpolate Points' commands both seem to do roughly the same thing, although the results a slightly different. Does anyone know what the difference is between the two commands?

    Thanks!

    CET
     
  6. Raggi_Thor
    Joined: Jan 2004
    Posts: 2,457
    Likes: 64, Points: 0, Legacy Rep: 711
    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    These two commands,
    _CurveThroughPt (Curve / Free-Form / Fit to Points)
    and
    _InterpCrv (Curve / Free-Form / Interpolate Points)
    do the same thing, but the first one lets you select all the points (as existing point objects) at once with a window, while the other lets you click (with snap) on each point.

    Different settings may give different results.

    Note: All curves can be edited by control points or edit points (on the curve),
    Command: _EditPtOn
    and
    Command: _PointsOn
     

  7. CET
    Joined: Sep 2005
    Posts: 114
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: Utah

    CET Senior Member

    Thank you, Raggi_Thor. I reviewed the manual a couple of times and that is the only difference I could find, but the two commands seemed to yield slightly different results so I wanted to be sure if there was a difference that I was using the most appropriate one. I'm sure now that the difference is due to settings. Thanks again for your help!

    CET
     
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