Re: Easy way of creating frames and stringers?

DELFTship forum Hull modeling Easy way of creating frames and stringers? Re: Easy way of creating frames and stringers?

#35071
otaku
Participant

HiHampus,

You may also want to do this:

– Create stations at places where you want watertight bulkheads

– Create stations at appropriate (if you go by Class rules for a given region/flagging) or convenient to you (fictional or notional designs) distances so that you later have them in place. Know that sometimes, either DS or your CAD program may “twist/kink” up some lines but you won’t know that until you try sweeping a line down a one-rail curve in your CAD app. Out of some 320 stations in my models, I sometimes have 3 or 4 stubborn, wanton, craze-inducing lines that don’t behave, and even regenerating them in the CAD app does no good. It sometimes takes convertion the line into another type.

– Create two faces of the bhd by creating two stations where bulkheads exist, the distance being the plate thickness of the bhd. This could later help you to avoid certain trimming issues that might be specific to a particular CAD vendor

– Create waterlines at locations of your deck plating — assuming you’re designing MODERN vessels in which “design for manufacture” is your rule, and thus your deck plating is horizontal, not sloped

— Turn on the wls and stns

— in Layers, create names for the watertight subdivisions (major watertight compartments) in your hull. Turn on meshes and assign them as convenient to you. This way, later in your CAD app, you can vastly more conveniently get out of the way any piece of the hull that is confounding your CAD activities as opposed to your (DS-based) HYDROS activities.

As for the bhds, when you export them, and when you look at a profile in D/S, the bhds will be easier to locate by eye.

Now, as for those meshes and waterlines, turn off the meshes. Now, select each waterline of interest, and CREASE that/those waterlines. What you end up with is plates or panels at each waterline and intersecting station. This might be nice if you assume you are designing a hull made of flat pieces rather than curved pieces. If designing a type of stealth ship, or just a very cheaply built ship, flat panels used extensively, as you probably guess, require probably no rolling, meaning all that attendant jiggery and press equipment is not part of the construction process, lowering some costs, probably significantly. But, that is beside the main benefit here:

You can arrive at better weight estimation/calculations if your hull is more conveniently broken down in logical places. Why try to estimate weight of a compartment if the sideshell and decks and stringers in that compartment are running the full length of your DS model? Also, the stations then are pretty much already broken down by deck and waterline, meaning you can build sub-assemblies in CAD if that is your fancy. But, the pain in this is that rather than having a limited number of stations from gunwhale to center of keel at bottom, you have that times whatever number of waterlines you choose to crease, +/- other modified areas.

Note: It can be quite time-consuming. The biggest most demoralizing part of doing it my way is that CAD and hydro vendors have very few if no two-way plugins, which otherwise could vastly speed up incremental changes or fixes when errors are discovered in finer-grained work within a CAD app. It is a major, major bummer that DS, Freeship/Hydronship, and ViaCAD and other CAD vendors don’t get together. If they did, a lot of vexing work could be streamlined, and poorer ship designers could avoid paying thousands of dollars per seat for CAD-design modules that they’ll hardly use regularly, but must pay for to get SOME utility out of the CAD app. (Imagine free-form designing the general hull in CAD, then importing to DS the various preliminary stuff, and assigning by layer the functions of those pieces and having the hydros further enhanced by the presence of those tiny little inclusions. Overall, it might not make much of a difference in this regard.)

Hopefully, this is useful information.