Hi,
I am trying to generate a ship hull form from station curves. Please find attached the Rhino file I have generated so far. I am not able to join the bow and aft portion of the hull with the midship portion. Can someone help me in generating this hull and teach me which Rhino commands are best used in such scenario.
Best,
Tava
KVLCC2.3dm (1.2 MB)
Hello - it depends a little on what the goal is, with the model - do you need accurate or approximate surfaces? Your current surfaces fall away from the curves more, or less, in different locations - is that OK?
-Pascal
The hull form will be used to generate a panel mesh GDF file for hydrodynamic calculations. The surfaces need not be very smooth or accurate. I am looking for a quick method to obtain a reasonable hull shape only.
Wouldn’t be easier, @tavaamitava, if you modeled just one half, and than mirrored (possibly with history) to the other side? Just an idea.
The half model also presents the same problem. I can not loft from one continuous surface to two separate surfaces. I am a bit new to modeling, so may be I am unaware of the advanced options in Rhino. So far I can not figure out is this is possible by just using the Loft, Sweep 1 Rail or Sweep 2 Rail functions.
Please let me know if you have other ideas.
KVLCC2_Half.3dm (840.5 KB)
I fiddled with your file for an hour or two. I’ll post the file, maybe it will give you some ideas. The key commands are _SplitEdge, _Blend, _Sweep1, and _BlendSrf wirh AddShapes option, and adjusting the handles with Alt key (http://docs.mcneel.com/rhino/5/help/en-us/commands/blendsrf.htm). I wasn’t able to get decent transition fast. Maybe if you spend more time you’ll get it. Be aware though, that these surfaces are not aligned well, isocurves are running in all directions, and you’ll get bumps anyway.
On NewSurface layer I put an example of a hull lofted if one swoop. I projected some curves (purple Curves2Project layer) on the old surface, filling the missing sections with _Blend.
You will probably will have to ask the marine people whether or not to use centimeters for hulls, and what tolerance should be so as not to get to many points.
Here is some videos on hull modeling, and complex surfaces:
https://www.youtube.com/channel/UCi90aaoO3-aZLVcWiuwL62A
and my 3DM: KVLCC2-fiddled.3dm (1.2 MB)
Thank you so much @0netech for giving me the resources to learn more and for the model. I will go through the materials and try first myself to regenerate the model by myself and seek further help if needed. Thanks a lot.
G’day @tavaamitava,
Do you have access to a CL section? That would help with the bow and stern surfaces.
What format file do you need for your hydrodynamics software? Do you need panels for CFD or is it a strip theory program that only needs sections?
This may seem funny, but I actually started from a surface model in IGES format (link). The hydrodynamic code I use, uses 3D panels. Rhinoceros export a *. GDF mesh file which is used in my code. The mesh generated from the IGES file was not very neat and hence I decided to create my own surface geometry. The method shown by @0netech gave me pretty reasonable hull form, however, due to not having the exact match of the bulbous bow and propeller section, the displaced volume for a given draft is coming little less than the published known value. I believe if I extract the CL curve from the IGES file and regenerate the hull, it might solve this problem.
