3D parametric Yacht Design

Hi Rich

Yes we are getting of the original path of the thread. But as I have already doodled my ideas I am able to draw a hull in ProLines very quickly which also calculates my hydrostatics I can then refer to ABS rules or any other construction rules for the basic scantlings, plating thickness, frame spacing ect though they may change as we get further into the spiral but that is not really a big issue at this stage I also know in a steel sailing yacht that the structure around the mast will require a bulkhead of some sort to take the compression loads which I assume as the same thickness as the bottom plating and later I will look at lightening holes access holes and thining the plating. It also helps a lot to look at other similar vessels a combination of these will very quickly get you close to a suitable structure. It is pointless to calculate the stresses on a hull to the inth degree based on a rig that may need to be redesigned because of the weight of the hull is a 5% heavier than expected, you need a starting point and I find that a basic calculation and observation of similar vessels is the key. For say a 13m medium to heavy displacement ketch with a full keel I would be looking at 12mm keel plating 6mm bottom 3mm topsides frame spacing of 750mm to 800mm with 5 full bulkheads which all but the forward and aft would have major cutouts, frames and stringers would be 6mm x 50mm T section the web being 30mm ofcours this would be a lttle on the heavy side but it give you the option of sheding weight if needs be which is easier than trying to figure out how to make it stronger because you went to light. I am assuming also that this is a cruising yacht that you are designing.

I use the contour comand in Rhino for drawing sections ect... but dont forget to offset thes lines the thickness of the hull plating otherwise the boat will be a little bigger than expected and will effect the hydrostatic calculations.

Regards Garry

Garry,

Thanks, I'm downloading the demo versions of Prolines and a couple of the other tools, not sure what the limitations on them are. I did my hydrostatic calculations by hand using data from the Rhino model, but I would love to run it through Prolines and see what it comes up with. Would you be willing to help if the demo version won't allow me to run the hydrostatics?

It's a 52m radius chine hull, yes it is a cruiser, but according to the calculations I came up with for the hull, it should be capable of some pretty good speed. So far I haven't found much detailed information on other vessels of a similar size to get an idea of materials. I'll keep looking though, all I'm looking for is a starting point, any rough estimates for a 52m as you gave for a typical 13m?

Where should I get a copy of ABS rules for reference?

I don't want to go off topic any more in this thread though, so can I send you a private message about this if I have more questions?

Thanks,

Rich

3D / 2D

Today it is hard to build 3D-models from the early beginning and to keep them through the whole shipbuilding process, because of the missing interfaces between the different 3D CAD-Systems, the missing 3D-equipment models from sub suppliers(all you can get are normally 2D-dxf files) and the missing ability to handle very complex and large 3D-models in a smooth way.


But never the less before Detail Design begins the following work has to be carried out:

Ship design
Specification
Loading conditions
Intact and damage stability
Manoeuvring and Seakeeping
CFD analysis
Powering and speed
Cost estimation, budgets
Time schedule, budgets for work units
Steel scantling plan
Calculation of weights
Bill of material and schedule
Block assembly plan
Machinery layout
Piping diagrams
Current one line diagram
Equipment list
Painting plan
Outfitting plan
FE-Calculation
Noise and vibration

After delivery:

Hull Condition Monitoring
Ship Operation Monitoring

All these activities have to take the same ship and the specific conditions at the shipyard into account. These plans are often made too late, are incomplete, faulty, contradictory or too inaccurate. The reason for this is the fact, that everybody must work independently and there is no common product and production model to guarantee the transparency of the information. These partly incompatible plans finally lead to considerable disturbances and much higher costs than necessary.

The EDP development on most shipyards has gone into the following direction:

The amount of different software packages has increased
The number of data files has increased
The number of inaccurate plans has increased.




As a new starting point we are trying to build up a 3D-model store under

http://www.boatdesign.net/gallery/showgallery.php/cat/3054

As an enclosure you find a picture how to the handle the 3D-interfaces between the CAD-systems in the best way. For the Rhino people: You should work normally via Step, except for the export towards Autocad. Use here Acis 4.0. If you have the models in the three formats Parasolid (.x_t), ACIS (.sat) and STEP (.stp) available you can act with them in most CAD-Systems like native files. With .igs you get normally a lot of problems.

What a great idea, I had been drawing very crude blocks to deal with the issue of engineering equipment generally made of a selection of boxes and cylinders of the diamentions gleaned from 2D drawings that I was able to download or find in catalogs. I will be using your site in the future when I can.

Garry

tartanski


Tribon has up to now the most professional 3D model database, with an extremely amount of models. But the main parts are missing, the service is very expensive, and they have the problem to update their models. We prefer for the long run the distribution direct via sub supplier.We are starting to cooperate with MAN ( the most important engine supplier in shipbuilding). You can configured and download their models via their extranet.

Engine suppliers are the most important players in equipment design. In the end we are planning that the people will be able to download as a starting point a whole engine arrangement incl. main engine, gensets, propellers, shaft, gearbox, coupling, exhaust gas lines, silencers, filters, pumps, preheaters, steel foundation, engine room crane and so on and so on, because all these parts belong to the gensets and main engines. Just look into the project guides from the engine suppliers.


For boat design it will be great if you have some models to share. Please upload them towards to http://www.boatdesign.net/gallery/showgallery.php/cat/3054

Cheers

Bernd

Hallo,
I am Naval Architect with 8 years experience with different 3d software for "big shipbuilding" (Cadds5i - Trident module for hull construction, and Tribon M2 also for hull construction - only one year of experience) and also 3d sofware for Yacht designing (Rhino, Multisurf, Maxsurf). I would appreciate Your opinion about using Catia V5R16 and Unigraphics for Yacht design (Yacht design meaning not only rendering but complete structural drawings, mechanical, piping, electrical, list of materials, ...)
Thanks in advance
BRGDS

Hi,

I and some big shipyards in north germany are productively using Unigraphics NX for their Steel, Piping and Designworks. I can't comment on Catia, I think Tartansky is more competent on this subject. The important thing to consider is IO (export and import) and the capability to handle VERY LARGE ASSEMBLY, because shipbuilding is a very complex and big project. You can model any kind of surface with Unigraphics. In my opinion, if you already gatherd experience in any 3D software, then it will be more comfortable for you to use Unigraphics or Catia. Somebody, who only used 2D software will have problems accepting a 3D software.

Coordinating piping for example is actually building the ship digitaly. You can check clearence, collisions and you see "life" what other do. Everything is in 3D space.

Actualy you can use any 3D software, but most important for the project is to use a collaboration data format that can be used by any 3D software. The tricky part is, that you have to maintain the version of your data every day! Thats why it is better to use ONE software branch for all CAD/CAE process.


cheers,

JMR

unigraphics tutorial

Hallo,
Is there Unigraphics tutorial for shipbuilding and is it possible that You send it to me (pdf)?

BGRDS
dbd

I use UG NX3. But I also use Maxsurf, Rhino, Acad and pencils. Parameterised 3-D modelling was a revelation to me, once I'd climbed the learning slope. As far as final production design output is concerned, two years into NX3 the only limitations I've personally come across are the ability to interogate a hulls hydrodynamics quickly (fine tuning displacement and LCB is an example, as Maxsurf or Woolfson is still invaluable here) and the rather frustrating issue of co-existing with other companies (equipment suppliers for example) software.
As for conceptual or initial design work, I doggedly cling on to my sketching and hand-drafting ability....even though top-end computerised 'sketching' software has been available for some considerable time, the 'imagination-to-paper interfaced via human hands' aspect of creating and designing is something that I feel should never be lost.

That's also for us the most important point for the long run. As mentioned already if you have the models in the three formats Parasolid (.x_t), ACIS (.sat) and STEP (.stp) available you can act with them in most CAD-Systems like native files. For the Rhino people: You should work normally via Step, except for the export towards AutoCAD. Use here Acis 4.0.

For UGS the in and output should be .x_t, because the system is based on Parasolid, further on beside that, you should produce a .stp (AP214) file. On the internet there is an tool available to translate files between .x_t, .stp and .sat up to 5MB http://www.steptools.com/translate

Form sub suppliers we would prefer .pdf catalogs with integrated CAD and other documents. Try these two examples.


http://www.archnav.de/Sauer_Marine_compressors_Test2.PDF


and


http://www.archnav.de/MaK_Al271240_starting_air_diagram.pdf


Cheers


Bernd

Dear Davit,

Up to now it is a demonstration. But we would like to press the sub suppliers into that direction.

-Using .pdf catalogs, with embedded documents and CAD-files. It is also possible to do it in a hierarchical way. Look at the diagram example.

-Check and translate the models via an internet tool like
http://www.steptools.com/translate.

- Put all necessary documents into one .zip file.


It would be great if CATIA, UGS or SolidWorks could develop this first appoach into a complete PLM solution with automatic generation of the different documents and handling via internet.



Overall the sub suppliers will only go into that direction, if the end users are asking for this kind of documents.


Cheers


Bernd

Re suppliers design info...
We have had some odd ones.
We requested a 3-D model of a generator sound shield...the manufacturer sent us a model of the complete, entire generator. The file was larger than that of the entire yacht it was to be fitted in.
This is promising we thought, lets ask the engine manufacturer for similar info...we got a 3-D rectangular box in return, although it was in a rather nice shade of green.
I'm quite used to the odd small components coming in with dodgy .iges info too, like a surface-drive leg that stretched to infinity and beyond.
On a more positive note, this situation is improving all the time, and from our point of view the 3-D design info currently available is already invaluable.

In UGS is it possible to produce automatically only the outer surface from a complete production model. Reintjes send us such a gearbox. The file size was reduced from 2000MB to 3MB. .iges is comfortable for surfaces but not for solids. Normally the 3D-equipment model should be a solid. MAN (engine supplier) is dealing with a software , which reduces the heavy production model into a simple 3D-solid CAD model needed by yards and designers.


Cheers

Bernd

Parametric design (by which I mean a design constrained by, and containing parameters that can be modified and edited) comes into its own when the design software updates the entire design instantly, as a whole.

This can be spectacularly effective even on the most complex of designs. (Talking UG again, sorry) If modelled in the right sequence, and with a lot of foresight, its easy to change (for example) deadrise angles, chine beam, headroom whatever, and then fully update the entire model at the press of a button. Even more spectacular when expressions are used, although its almost heartbreaking to see your latest high-lift hull design reduced to thousands of cells in a spread-sheet

So far so good....the downside is the level of competance a designer needs to achieve this. Do designers spend sleepless nights and lose their hair attempting to become profficient at this level of modelling, or do they relinquish some of their design input, passing a basic idea over to expert modellers who dont know their ass from an Arneson ? I've done both, and its tough. Frustration at both levels...spending modelling time that should be used for pure designing, vs the continual 'over the shoulder' monitoring of the modellers who misinterpret your original vision and thought processes.

In my case, the prime motive for Parameterised 3-D design being introduced into the office is to feed the 5-axis machine that machines our hull and superstructure mould tooling (GRP product). Secondary benefits are obvious and have already been mentioned by others in earlier posts. Above a certain hull length though, our mould tooling is hand built and as such the design could be hand-drawn complete with a table of offsets. As much as I miss all that however, I'm staying with 3-D. Its the future, and yes, a 30" Apple flat screen helps a lot.

Streamlining the process

You couldn't be any more correct than this statement in logic. We want zero -computer- interference as we allow our creative juices to go about emotive problem solving! I got a 21" Viewsonic Graphics monitor thinking size would help, but now I have to sit further back to avoid vertigo. (Not to mention an advanced case of tunnel-vision.)

I am completely stumped at the moment because I don't do AutoCad. And, I've enjoyed watching architects develop these skills since '81. Of course, simple planar building design can be done on some very simple software, regardless of the advantages of the associated database calculations via AutoDesk, etc.

At this time I am trying to design something that I can only equate to a combination of a swiss watch, and the belly of a whale. God does not seem to be so easily amused. The only way I know to get there is to use a pencil, and to think orthographically, but with a distant vanishing-point on the horizontal plane. Next I transfer the arrangements into 2D, and again, back to 3D with full perspective. All complelling, none of it very valuable in today's robotic Mfg. scheme.

So, teach your kids in AutoCad, and restrict their TV viewing to include plenty of computer games. Otherwise, they may grow up to be just another frustrated illustrator like me.

Hey, I feel your pain MaxResolution.

What got in my way with the modeling programs is that they demand you use a constructive approach. Make a lot of little parts and stick them together. From a conceptual angle it would be far more intuitive to start with a lump and whittle it here and there into the needed complex shape. But so far I have not heard of a modeling program that is happy with such an approach.

old dog Kelly

That's the catch

Yeah, I got that same program. So far, I made a colony of space shelters and a really bad single engine Cessna, then I put it in the 'utilities' folder after a whiplash fly-around. I went back to Freehand, and then to free hand with a scanner. Ostensibly, it's no problem doing component division and free form curves in real Cad, so there is an immediate benefit, especially in making measurable & traceable scale model parts.

On a positive note, have you done the virtual tour of the Herreschof museum? Man is it fun. They have so many hull shapes in one room it took me about a week to traverse every angle. I really got side tracked by that historic chart table. This led ne to explore some great woodworker's shops, but even the most acclaimed one of all hardly seems up to the task of focusing on the curvilinear needs on boats. They all cop out, mostly doing single plane laminated face panels and such. Sure, these laminators are into rocket science compared to the door shops, but I hardly see a ray of hope for the average needs of yachting customers.

Given a million dollars, I suppose some sellers get their money's worth by going to these traditional (housing) interior designers, who can outfit her with Chippendale for the photos, and unload it to some Vegas hot-shot with new money. Does anyone ever ask: "Is that slender bronze Modiglianni sculpture really appropriate on a boat?"