Yacht design in Rhinoceros 4

Shell Stiffeners

How Do You Model Shell Stiffeners In Rhino?

 

You may have better luck with responses if you post this as the start of a new thread.

 

Typically I've used the 'extrude curve normal to surface' command.

This is a good start for the base nature of a shell stringer. After that you might want to consider the 'rail' commands.

You can create the surface curves from projections or divisions of a surface.

 

dear acuttle
thanks a lot. it s a good method but if shell longitudinals have angle other than 90 degree
with shell then it can not be useful.

 

No, that is true, alot of (if not most) longies are planer or normal. If they're normal it gives you a good weld on both sides and better stiffening potential. Planer stiffening is easy to put in with regular offsets.

It sounds like you have a specific application in mind?

If you particularly need to put in stiffners with a changing angle (maybe to tie into other structure) you can work with the 'rail' commands (maybe single but likely dual) but take care that the offset stays constant and that you don't produce any strange kinks.

 

what is the reference of designers to put longitudinals on shell in fore and aft?
do they design them in such a way that they look horizontal in profile view?

 

I'm not sure I quite understand what your asking for, are you meaning a planer longitudinal? Certainly they look horizontal in the profile view.

To put a stiffner in like that you can section (or project to) the shell at that level and then offset the section line by your stringer depth - then produce a swept rail from the two curves (under the surface commands).

 

in some cases i have to project an inclined line in profile view on shell to produce shell long.
i want to know this line must be straight or may be it can be curve?

 

Without seeing the situation it's harder to say but I don't seen any reason why not.

 

I've been posting some how-to's on using an existing lines plan to learn DraftSight and Rhino. DraftSight is a free AutoCAD alternative made by the same folks who make SolidWorks and Catia. See www.3ds.com/DraftSight.

The how-to articles are here.

 

thanks

 

adt2, I'm curious about your reasons for working both DraftSight and Rhino. Images can be imported into Rhino and the curves traced to create splines directly in Rhino. That eliminates the need to learn two sets of software.

 

Mostly habit. Before I started learning to use Rhino, I did all of this in AutoCAD. When I started to learn Rhino, I followed the process (more or less) I outline in my "how-to" posts mentioned above.

As I get handier with Rhino, I'll no doubt try to eliminate as much of the non-Rhino CAD work as possible, but as of right now, 2D CAD is still my "comfort-food" medium.

 

Although I always prefer to work with Maxsurf, I can think of some ways for Rhino. I think many people take one surface and then they reshape it to form one side of the hull but I don't think that such a hull will be smooth enough. (but it's possible that I might be wrong).
If I used Rhino for hull model, I would draw different sections, define keel and deckline and use "sweep2" command but I know that it's too much work.
Another option might be drawing waterlines for specific heights and using "loft" command.

 

Yeah, the Surface>Loft command mostly creates slab-sided hulls between any two curves (like the sheer and the chine), but a lot of times that's all that's needed. I've found that as I try to draw more hulls with some shape to the topsides, I have to draw a section curve through the "curvy" bits of the hull and then use Surface>Sweep 2 Rails to get a surface with some character. Doing it that way is a bit more work, but I don't think I'd go so far as to say it's "too much work."

As far as surfaces not being smooth enough, I can't speak to that other than to say I'm not sure why Maxsurf would create surfaces any smoother than those created in Rhino, assuming the user knows what he or she is doing. I myself have created some ugly things in Maxsurf; I choose not to use it because a) the student license is too restrictive and b) the user interface isn't much to my liking.