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Thread: wrapping a surface around a cylindrical object

  1. #1
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    Smile wrapping a surface around a cylindrical object

    Hi

    Does anyone now how i can wrap a surface around a cylinder in Rhino.

    Thanks

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  2. #2
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    You can try Flow or FlowAlongSrf. Have a look at the help for how it works... --ch



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    Smile

    Thanks CH will give it a try



  4. #4

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    It's in the help file in v3.0.
    The basics are, unroll cylinder
    draw curves on flattened piece
    applycrv - select curves - select cylinder



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    Thanks that sort of works but what I wanted to do was take some extruded stars and wrap them around the cylinder.The tips you gave me wrap the stars around but only in 2d form, am i missing a step.

    Thanks again



  6. #6

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    chmillman had the proper way:


    Assuming you have your cylinder, and a closed polysurf for your star, do the following:

    1) create a circle with a diameter of your cylinder, and place it on the the backside of the top tip of the star, using a quadrant of the circle.

    2) draw a straight line with a length = circle circumference, place it at the same tip point of the star, at the line's midpoint.

    At this stage, you have a 3d star, with a horizontal line centered on the tip, with a circle tangent to it behind the star.

    3) Now use the FLOW command. Select the star, select the straight line as the original flow curve, then the circle as the destination flow curve. Voila. (you may get an unexpected result depending on WHERE on the circle you pick, so try a different location if it is wrong at first.)

    Attached is a jpeg showing it after doing the above. Both the original star and the new FLOW'd star are there.

    Good luck.

    Attached Thumbnails Attached Thumbnails -flow-jpg  


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    Default

    Thanks JD, sorry I didn't have time to make an example yesterday. Attached is one.
    As you said, depending on how the objects are arranged, you may need to experiment a bit with which ends of the curves to pick.

    This can also be done with FlowAlongSrf - it may be easier to visualize the result. In this case, Explode the cylinder, use Unroll Developable Surface to flatten a copy of the cylinder surface on the Top CPlane, make your stars on that flat surface, then use FlowAlongSrf to flow the stars from the flat surface back to the cylinder. Again, depending on where you pick on the two surfaces, the result may differ... You need to experiment. another example is attached.

    You should be able to BooleanUnion the objects together afterward if you want.

    In both of these methods, there will be no draft angle. In some cases, there may actually be negative draft, so beware if you want to machine the surfaces. You could extrude the stars with draft before flowing if you need. --ch

    Attached Files Attached Files


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    Smile

    Thanks for the help i got it right.



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