Subdivision surfaces
› DELFTship forum › Hull modeling › Subdivision surfaces
 This topic has 3 replies, 3 voices, and was last updated 11 years, 8 months ago by Liliana.

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July 10, 2011 at 19:33 #34993Alan RockwoodParticipant
Can anyone explain subdivision surfaces for me? I understand that it involves modeling the surface by breaking it into smaller and smaller pieces, but what is the mathematical description of a subdivision surface? Preferably, explain it in plain language, maybe with a few wellexplained formulas to illustrate key points.
Also, can Delftship export a NURBS equivalent or nearequivalent to a subdivision surface?
Thanks.

July 11, 2011 at 19:42 #34995MarvenKeymaster
See the PDF document below for a mathematical description of a subdivision surface similar to the one used by Delftship.
As far as conversion from/to NURBS is concerned: Uniform nonrational Bspline surfaces can be presented by subdivision surfaces exactly
 Nonuniform or rational surfaces are approximated
 Conversion to NURBS is also exact
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July 12, 2011 at 02:40 #34996Alan RockwoodParticipant
Thank you for the pdf Marven. I will try to read it and understand it.

July 14, 2011 at 16:49 #35000LilianaParticipant
Marvin,
Thanks for the paper, I read it as well, but however im unsure of your previous statement. To clarify, are you saying that importing a NURBS surface into Delftship means that the surface would be approximated however exporting Delftship into NURBS would be exact?
Thanks so much for any help.


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