Developable surfaces in Rhino - Plywood

Discussion in 'Software' started by IMSACAD, May 5, 2012.

    Joined: May 2012
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    Location: Stockholm, Sweden

    IMSACAD New Member

    Hi, does anyone have experiance how to set "Twist tolerance" in DevSrf when modelling for plywood.

    I realize that it depends on the thickness/type of the plywood and the size of the surface and I know that plywood doesn´t tolerate much twist -- beeing new to this it would be great with some general direction.

    For instance the topside surfaces for a "typical" 30 ft hull in 12 mm plywood.


    For reference I´ve been looking at a french boat "Fox 10.20"

    It seems to me that the chine/second surface from the top has some twist towards the bow - in comparison with the topsides and bottom surfaces which seems to have more constant angles. Moreover - by looking at these pictures it does not feel like there is much convexity in the bow sections of this surface. In Rhino I get this kind of flat developable surface with 1)* DevSrf having the "Alignment" option set to "Shortest".

    -in comparence with 2) an extended DevSrf with alignment set to "Least twist" or 3) a Lofted developable surface -which both - produces convexity in twisted regions.


    I am currently working on a multichine hull with similar division of surfaces as the Fox 1020 and also with a plumb bow and it is the plumb bow that dictates that this surface has to end with a straight section/edge rather than a convex shape in this part of the stem -- I get a satisfactoy surface here with metod 1)* with a twist tolerance of 5.0.

    - but can I trust this result?
    - is the tolerance value to high?
    - would 12 mm plywood conform to this?

    Many questions and hard to put in writing, I´d be happy to submit Rhino models if someone experianced understands my problem and would help me.

    Thanks and Best Regards
    Christian Wallgren
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