unroll surface in rhino for shell expansion

[pavel915]

I want to unroll the hull surface in rhino ; to get the shell expansion drawing.
but it says that , this object can not be unrolled.
I could unroll any hull surface importing from maxsurf , i could get the shell expansion drwang ,
Is there any solution to it?

[CGN]

Hi Pavel,

you can't unroll becouse is a double curvature surface the one you are trying to develop.

yes you can "unroll" surfaces from maxsurf but they need to be developable or close to.

no you can't get a shell expansion drawing, if you are actually talking about shell expansion....but if your are talking about plate layouts (developed plates) yes you can (you may need to use software like shipcam, touchcad workshop or any other that can handle double curvature surfaces)

Yes, do shell expansion by hand, and do plate development using some software or find some technical papers on how to "unroll" by hand (lofting and layout)

[Steve Baer]

Hi Pavel,
We are prototyping a new surface flattener that works on non-developable surfaces. The plug-in works in Rhino 4
http://en.wiki.mcneel.com/default.as...lattening.html

Thanks,
-Steve

[raw]

A work around is to get the surface as developable in maxsurf as possible, then import to rhino.

Once in rhino, recreate the surface using edge curves. <loft with straight sections> which can be unrolled with rhino. Take it back to maxsurf if you need to.

I have done it this way a few times.

raw

[CDBarry]

The traditional shell expansion drawing is not a true expansion, it is a plot of true girth vs station or frame.

You can do it by hand by interogating girths (to seams, longs, etc.) from the lines drawing, and then plotting them though it is tedious.

Note that expansions imply plate distortion, so there is no unique solution - it depends on the distortion field.