Thought to Hydro to Cad to Paper and Beyond.

Interesting discussion. At IBEX in October, there will be a panel of naval architects discussing this very topic--What software do you use and why? I will be on the panel, which will be Session #202, 1:00 PM to 2:30 PM on Tuesday, October 2, 2012, in Louisville, KY, in case anyone is interested in showing up.

I follow a routine similar to others posted here. Sketches come first, either on paper or in AutoCad (I have had AutoCad for years, and I am very used to it). Ultimately, what gets drawn in AutoCad like the profile line, sheer line, and deck line in plan can be imported via dxf into my 3D software, ProSurf. I have had this for years and am also very used to it. It is very easy to use when manipulating surfaces, and it has built-in hydrostatics and stability software so that I can check hydro and stabilty on the fly. All my 3D modelling for technical accuracy is done in ProSurf. When I am ready for renderings, I export to Rhino via iges and continue with fine-tune modelling there, such as adding colors or materials, windows, the rig, etc. Unfortunately, there is no other reliable way other than iges, messy as it is, to transfer between 3D modelling programs. At least, going from ProSurf to Rhino is messy--there is a lot of junk linework that gets transfered, but this is relatively easily deleted. Once in Rhino, the iges transfer going back or to other programs is much cleaner. So, to summarize, technical 3D in ProSurf to get the shapes, hydro, and stability correct, and Rhino for rendering. Then onto AutoCad with exported 2D shapes for all technical drawings.

One unfortunate problem with Rhino is that by the time the file is finished, the size of the file is huge, 10s or 100s of megabytes, so it cannot be emailed to the client--has to go on a disk. Actually, I learned through this forum of the 3D viewer in Adobe Acrobat is pretty cool--lets the client manipulate the 3D image in apparent 3D space with the mouse--but I have yet to buy it, I think the price is US$95.00.

Once the ProSurf model is complete, I create a lines plan with the a few key-strokes. This can be exported in 2D or 3D via DXF to AutoCad. I use 2D. All my drawings are 2D, it is just a lot easier to work in 2D.

Somewhere along the line in the design I will do powering calculations through NavCad to get the engine and propeller specifications correct. I don't use any aerofoil software to calculate things like rudders, keels, or rigs, and the reason why is because I know enough about proper shaping to calculate what I need for the design for the overall shape, size, and volume. So many other factors go into keels, rudders, rigs, that whatever ideal shapes come out of software, they are going to get modified, guaranteed, simply for practical considerations of design restraints or construction. For example, the ideal keel may be an 8' draft, but the client wants a 5' draft. The rudder may ideally be longer than the keel, but you never make the rudder longer than the keel, it should always be a bit shorter. I know the size and shape of the rig, but the sailmaker knows a lot more about sailmaking to fine tune my basic requirements so that the sails are built with all the proper bells and whistles.

I also use Excel spreadsheets a lot for engineering scantlings, weight estimate, mast design, and anything else that might be needed.

All the engineering work goes on more or less in parallel with drawing. In AutoCad, I draw in model space with 3 orthogonal views simultaneously, rather than in 3D. It is just a whole lot easier, particularly when you are putting notes and dimensions into a drawing. So what I draw in profile gets projected into a plan view above and an end view to the right or left. I also do a lot of cut/copy and paste, going from one drawing file to another. Any one drawing file may have anywhere from one to 30 or more drawings in it. Hull frames is a good example. ProSurf gives me the frame shapes in 2D, and I line these up in order frame by frame to create the actual frame shape, complete with hull skin thickness, frames, flanges, cutouts, etc. On my Globetrotter 66 that I am designing now, there are the hull lines, 4 copied drawings from preliminary structure and general arrangement drawings, and 27 frame drawings. From these frames I also copy and create the patterns for the cut frames in the same file. These cut shapes have to be closed loops for the cutting machines, so taken directly from my architectural pattern, I make sure that the shape of the pattern is a complete polyline closed loop on every frame.

I take my drafting skills very seriously. A well done drawing tells a story right to left and top to bottom, invites the eye to examine the detail, and is easy to read. Don't forget to leave a little bit of white space on the printed drawing to give the eye a rest. And don't, for gawds sake, us all caps in writing text. There is nothing harder to read than notes and descriptions written in all-caps. Best to use a nice simulated hand-drawn font with normal capitalization as one would find in a book. Draw a border and title block around every bona fide drawing, and keep a record on the drawing of changes and dates, including the date when the drawing was originally issued, Rev. 0. I see a lot of bad drawing in this business, from people who don't now how to dimension properly or can't figure out how to control the sizes of arrows, text, and units. 3D drawings are mostly useless for proper analysis of details, areas, centers, dimensions. They cannot be easily copied or manipulated when necessary to generate other drawings.

I also work on a black screen background, both in Prosurf and in AutoCad, but a gray or pastel color in Rhino. Colors of different lines and features show up much better against a black background than a white background. In AutoCad, I use the color codes to assign lines widths so that when the drawing is printed out, there are 5 different line widths for various features and drafting technique as required. Each width is created by multiple colors which gives me variety in drawing. I know that some people can draw with the different line widths directly on a white background on the screen, and that's fine. I am just used to drawing in color--my brain understands what I am drawing intuitively as the colors mean different line widths. I used to have my own very expensive HP plotter (was the price of a small automobile) but I found the cost of maintaining was more than it was worth for the amount of plotting that I actually did on it. I had to literally throw it away to recycling--wasn't made anymore and no one was available to service it. Most clients have access to a printing service, so I now print to pdf files, D-size (24" x 36") for the client, and tabloid size (11" x 17") for my in-office file.

I had the opportunity years ago to switch to Solidworks which incorporates 3D modelling (in general, not necessarily keyed well to designing boats) and technical drawing. I found it a totally different philosophy of modelling and drawing, and way too interconnected. I am used to 3D surface modelling and 2D drawing in AutoCad, and I did not want to spend the money to learn something new that would not necessarily give me any advantage. It was just different, and I could see the potential of creating too many problems when trying to do good drawings. You don't need to draw all details in 3D, 2d is fine in the vast majority of the cases. On the shop floor, anyway, the drawing that is used by the workers is a 2D piece of paper, not a 3D box or space. 2D is the end result, so I kind of just shoot straight for that.

Again, interesting discussion, and maybe we'll see some of you at IBEX.

Eric

 

Eric, thanks for the description of how you work and some of the rationale behind it. I'll be at IBEX.

How do you provide the hull shape to the builder; table of offsets or electronic mathdata (CAD files) ? Two designers of custom sailboats in Maine told me several years ago that the builders they work with (builders of higher end pleasure boats) want math files which can be used as the basis for CNC cutting and milling, full scale plotting, etc.

 

Hi David,
It varies. Sometimes they want full-size printed patterns, others want me to make the patterns and send them electronically by email (which I prefer doing so that I control the joint detail, particularly with metal boats) sometimes they want the 3D surface model so that they can make their own patterns. As long as you have the 3D surface model, you can supply whatever hull form format is requested. I have found that the traditional lines plan and table of offsets are the most useless and archaic forms of hull design definition these days. I produce a bona fide lines plan, typically, but don't bother with a table of offsets. Everyone is somewhat computer literate so that manipulating a 3D model is actually quite easy for a lot of them.

When I did the hull design for Nick Hake at Hake Yachts for his Seaward 46' sailboat hull, he described to me what he wanted for overall shape, I shaped it to his liking and approval. We then discussed how to make the plug, getting into the nitty gritty detail of the precise laminate makeup and thickness. I had to offset my hull surface lines that distance inward so that the plug, once finished, was at precisely the right original hull shape. Once the plug laminate and thickness were decided, I talked with the people that were going to actually cut the plywood hull stations and made the stations, with fairing and alignment guides and notches, to their liking. I created the patterns in AutoCad in a single drawing file, and outported that to an EPS file format. From this EPS file, they were able to drive their cutting machine. They still had to set the cutting head path on the file that I sent them. These cut plywood stations were then sent to Hake Yachts where they built the plug, then the mold, then the boats. You can see the story on my website (last story in the long article): http://www.sponbergyachtdesign.com/Patterns.htm.

Introduce yourself to me at IBEX, it would be good to meet you.

Eric

 

Great input everyone.

Eric,
I was very interested to hear that you draw in 3 space. Am I understanding that you are drawing 3 dimensionally so that changing your view orientation will allign the elements properly for your selected view? I had been drawing in 3 space (model space) for years, but in a different manner, I believe. My profiles and planes and stations will typically intersect based on the plane or section where the view would be taken from. If I understand your method correctly, you have taken it a step (or ten) further if your view port selection gives you a 2D projection from your 3D "model".

My limited ability 3D cad was horrible at modeling, so I had essentially thrown in the towel on that part of my boating designing ability. The DXF output from Freeship was suitable enough. I could/can built a fairly accurate model and design in enough suitable structure that most planar surfaces within the model were/are defined in the export file. Unfortunately, my software currupted file files one too many times and I'm now trying to figure whether a new system is needed of if I should continue with the old, but with new software.

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I find it very curious that there is not an export function in to industry that allows for a direct and complete transfer of a model for one software to another. Some recent reading reveal that when data is converted to a tranfer format, in many ways the model is deconstructed and often(always?) degraded from it's original format. I know little of the specifics of transfer formats. Mostly I am aware ony of what works for me. The DXF from Freeship is the only format my current software accepts from this source. It renders nicely and the polylines can be converted. The mesh output, I am finding out, is only good for it's multitude of verticies that can be selected for creating splines for lofting and skinning.

I have two CAD packages that accept IGES as an import format, but neither accepts the IGES export from Freeship. Somewhat frustating as I can export a DXF from Freeship, import this into a CAD package #1 and export it again as an IGES. The IGES from CAD #1 can now be imported into CAD package #2. The IGES file in CAD #2 is brought in as a surface and I have had varying luck in getting this surface to thicken into a solid. I get dizzy doing this at times, but #2 CAD has the potential to bring in a surface directly and convert it to a solid. A direct IGES import would be ideal, but I'm afraid the second generation surface is causing some kind of conflict or the original DXF conversion has degraded any surfacing aspect of the hull. The point being, I am starting to pull out my hair that isn't already falling out.

I believe that Ineed a Hydro package (I've been starting to look at ProSurf) that can comminicate more directly to my CAD package, or vise-a-versa. Ideally, I won't have to reconstruct the entire hull that has already been constructed elsewhere.

An aspect that hasn't been mentioned, yet is the modification of a design and the downstream drawing changes that must occur and whether they can happen naturally as a function of the software in use. I believe that the whole/primary reason for modeling a vessel is for a fairly automatic creation of drawings through a systematic selection of section views. Any changes in the model then flows downstream and is immediately incorporated into the ships prints.

Thoughts?

 

LP,
I operate in only one viewport. See the screen shots that I made of my Globetrotter 45 design which show two views of the same thing. G45-01 is with the "drafting" layer turned on to show my construction lines for projecting from one view to another. From a point on a plan view, for example, I draw a line to the cross-hairs (orange "X"s throughout the drawing) and then project down into the cross-section view which is located on the same design waterline as the profile so that the height of that point is correct. The hull cross section is copied from the hull lines, imported from the lines plan which was created in another drawing (copy/paste). The second screen shot is the same thing with the "drafting" layer turned off.

Reading the drawing file from right to left, on the left side are my color codes for printing. These appear in just about every drawing file. To the left of that is the sail plan with the red border around it and the titleblock in the lower right corner of the border. Next left are two drawings, the lines plan which was created in another drawing file and copy/pasted into here, and below that, the general arrangement plan and profile. Next left and lower are cross-section views of the general arrangement. All sections were originally created on the same waterline as the profile view to the right, but when the sections were complete, three were moved lower in the drawing to create the actual drawing with border and title block. To the left of the sections is a smaller drawing (different scale) that shows construction details. Above that in the upper left hand corner of the workspace is the outside deck plan and the end views. These were created in the work space closer and in line with the general arrangement profile and plan views, and then moved and rearranged to create the drawing with the border and title block.

When I print the drawings, I print a "Window" just outside the border, and the color codes are already set in code files in the printer function so that the appropriate colors will print out most bold (red), and step down in width with green and blue, then again with yellow, cyan, magenta, and orange, then next with white, gold, and sky, and finishing off with the finest lines of dark gray, light gray, pink, light green, and dark green. I actually have two sets of color widths with these colors, one set is for printing large drawing where the widths of the lines needs to be bolder in relation to the scale of the paper, and then another set which are finer in proportion for printing at tabloid and letter size.

My hydrostatics and stability calculations are done only in the surface model program, there is no point to trying to do them in the AutoCad program. By the time I start actually drawing the boat, the hull shape has to be "cast in stone" so to speak and will not change. ProSurf can import and export either in iges or in dxf, which I can read directly into AutoCad or into Rhino. You don't need iges to draw in 2D in AutoCad, you only need dxf because mostly you are just dealing with polylines at that point, not splines. When I export the lines plan from ProSurf, I can export it as a 2D drawing so that all the linework for plan view, profile view, and body plan are all in the same plane, the 0 layer in AutoCad. I can shift them anywhere from there, but I always stay in the same viewport.

What you propose, to have completely interactive shapes and drawings, is actually available in Solidworks. From my point of view, that is too much interconnectivity. Generally, I have found that there are very few changes that get made--only one boat is built as most of my work is custom one-off boat design. For production design, my record has been that the builder pays for the first design, and then he willy-nilly goes off and makes changes, but does not draw those out, there are no new drawings. (He'd have to pay for them wouldn't he, but he already knows what he wants to do, so why pay extra money to draw it.) At least, that's the way it seems to work with an outside designer. If the designers are in-house, then there is probably more documentation created.

Also, drawings do not get created automatically. In Solidworks, if you want the table to appear in three different views, you have to create the solid model of the table first. That is, ALL the details have to be created first, and for me, that is just way too much 3D modelling that makes the drawing huge and cumbersome. I much prefer the approach I use which is to create the details separately in each view with linework, not 3d models. Then, of course, you have to add notes and dimensions, and space is required to fit that all in. Sometimes, you need to move object around the drawing space in order to fit in the notes and dimensions. Sometimes you need a blow up details off the to side. I'm not sure how all of that is done in Solidworks in 3D, but I found 2D drawing very versatile. And, by working with multiple drawings in orthoganol views in the same drawing file, I can keep track of minor changes very easily.

That's some input in a nutshell.

Eric

 

This method appears to be the electronic version of how I learned to draft on paper by tracing and using a T-square and triangles to transfer information from one drawing to another and from one view to another within a drawing.

The auto industry (or at least the major manufactuers and their suppliers) has moved entirely to 3D math modeling for everything beyond initial sketches. Initially 2D drawings were created from the 3D math which required considerable work. But my understanding is now 3D math data is the primary method of conveying information with materials, surface treatments, tolerances, and other information and annotations embedded with the math data. A major requirement for the shift from "drawings" to "math data" was that suppliers became capable of working with the math data and providing math models of their parts which required significant investment and time on their part. Once everyone was able to look at math data and became used to using it as the primary design method drawings were redundent.

Of course the auto industry is totally different than the custom or even low volume boat business, both in terms of production volume and the number of people involved in the design. An industry closer to boat building is architcture and building construction. My understanding is that industry is still largely drawing based (with paper drawings still being an essential part of everyday life) but 3D math models are beginning to make significant in-roads, particularly for buildings which are not totally rectilinear.

 

This is very interesting because it leads to a direct benefit to the end user. My brother-in-law worked for Chrysler for many years in a number of engineering functions. I asked him once why, did practically all of a sudden, we were seeing cars that could go 100,000 miles before a major tune-up, and he said it was because of the 3D math models. All vendors worked to the same math model, so if you had to make valves, for example at one manufacturer, and cylinder heads at another, the same valve-head model was sent to both suppliers, and NC milling machines cut from the same 3D model. As a result, parts fit so well that they wore out a lot less quickly. Therefore, 25K or 30K mile services automatically went to 100K service milestones, and even then, service and adjustment is minimal. This works well for complex machine and molded parts. Ever notice how well automobile parts--fenders, lights, windows, handles, latches, vents, etc. fit so nicely together? It's all because of 3d modelling in a master model.

You are correct. We see some of that in boat building, for example, in the milling of a hull or deck. The designer's 3D model goes directly to the milling shop for milling the plugs out of foam. Because it is all usually plastic materials molding, and finish has to be supreme, the plug parts still require a lot of hand labor to make the final finish. There is also the matter of making the support structure for the plug and mold which all has to be "stick built" in place. Can be done in 3D, but it still requires hands-on labor and detailed drawings and specifications to actually direct the crew on how to build. But with sophisticated computer talent, a lot can all be done on the computer first, particularly with complicated shapes like deck molds, and sent to the milling shops for cutting and finishing.

 

This is somewhat limited to design type and methods of production as you noted Eric. In the case of composites it can help a lot.

In the commercial field, which I am in, you always need paper drawings.

I recall being at one yard where the DO was trying to be "sophisticated" and appearing to use "high technology". They were modelling everything in 3D...wow, looks great. Yet the poor fabricator was getting very confused. I asked where the drawing was (as I was asked to assist on some problems) and the draughtsman ran away to the office. About 5mins later he came back with his laptop in his hand and was trying to explain to the fabricator using his 3D model what he wanted.

On the one hand you may say, amazing, complex problems or resolutions can be now taken down to the shopfloor so "they" can see the difficulties. Isn't 3D great and having mobile computers that allow this to occur.

Eeerrr...nope.

This was a classic case of using a nuclear warhead to crack a nut. The poor old fabricator just wanted a drawing show him what to do. But the DO were not skilled in production drawings and understanding what is required to build a boat. All they knew, was how to drive their fancy software, they felt they did a good job!

Communication is the key. Like Eric noted above, when i review drawings from the DO (or when i do my own), if it takes me more than 5 or 10seconds to look for something which is either referred to on a drawing or is the MO of the drawing, i send it back. The fabricator wont want to spend time hunting for information or details on a drawing when s/he is being pressed by their Production Manager to finished the boat. It wastes far too much of their time to down tools, climb out the boat and go and find their supervisor and then wait to get an answer from the DO. Result is, they usually do what they feel best when no information is present, and often it is not what you intended them to do too and ends up a poor job and repaired, at more time and cost.

If you can't produce production drawings that fabricators can interpret, to ensure they build as designed, then all the 3D or even 2D software wont help you. This is slowly being overlooked by the technorati in their zeal to make everything a "one stop shop" and press a button.

 

Corrollary to Ad Hoc's story, my wife and I recently went on a cruise ship to Alaska. We had dinner one night with the Chief Engineer of the ship and the head electrical engineer. The next day, they gave us a tour behind the scenes of the main engine and machinery control room. No windows looking out into the machinery space, no large panels with dials and gauges as I was used to seeing on the Esso tankers in an earlier life. All the machinery was controlled by Linux-run computers, views being supplied all by video cameras onto television screens. At one point, the Chief Engineer expressed his concerns about the company's (and their suppliers') dependence on software, and their growing disregard for having people on board who knew how to service machinery and fix things. When something breaks, you still have to go down into the ship and wield a wrench or a hammer and screwdriver, or lift that bit out and put another bit back in. "Give me gauges and tools," the Chief said, "not this computer stuff."

In boatbuilding, the shop floor is where it all happens, that's where the workers are using their hands to put the boats together. They have to be shown what to do with well-detailed drawings. The drawing is a 2D format, it can show perspective views that suggest 3D which can be helpful. But 2D with notes and dimensions is an essential necessity.

 

I see the need for 2D printed material. That is one of the themes to this thread. One of my struggles right now though is a transition in software and maybe my design process. I'm trying to take my designs to a point where I can say "I'm done." I don't feel I can can do this until I can print a copy of the plans to give to someone and reasonably expect them to build said design. Some of my drawing processes are similar to Eric's so that gives some confidence that I have not gone completely astray in the partial drawings that I have accomplished so far.

I am also evaluating my piece-meal drawing process vs. what could be accomplished through modeling. With my previous software, the modeling accuracy was not such that I could section a hull and expect that representation to accurately protray the true hull section. Adjacent parts would not be truely adjacent. Colinear parts would not truely be colinear. A representation of the section cut would be the best that I could expect. Today's (low end to moderate?) software packages have progress over the years and may now have the accuracy and ability to make modeling a reality for a person that designs on my level.

I would like to move beyond piece-meal drawing if it is at all possible. I'm not implying that piece-meal is inadequate by any means. I've done enough of it and changes can be a bear if it is something major. Definitely something to be avoided. I feel like I should be able to model a countertop, a frame or a bulkhead as quickly in 3D as I can draw it in 3 separate views in 2D. I may be horribly deluded, too. Ironically (?), I almost never get that far in the model. Since interior componentry is predicated on hull geometry, I fall down before I ever stand up. For lofting and skinning of a hull or deck, my softwares deal with rectangularisms reasonably well, but triagularisms poorly. The stern section, the sheerline and the keel to bow line make a hull triangle that I have difficulties in modeling. Meshes work great up until the keel line transitions to the bow line and the X component turns into the Y component. The deck centerline, sheerline and stern deck edge form a similar triangle that causes me difficulties. I feel I should have a better grasp of these modeling concepts, but I stopped trying to work them years ago and have only attempted them recently because I have recently acquired new software. Needless to say, it's hard to model the interior if you can't even get the exterior modeled. Once the hull is finally modeled, it can be the cutting tool for the interior componentry.

Ideally, I shouldn't have to model the hull, or at least define it's shape, as I already have a hull definition in the hydro software. I've come close to this solution. Compatible softwares that can export/import the same format directly is a step worth persuing. Importing a functional model that can be manipulated directly would be the ultimate in compatibilty. This is the point I am approaching right now. I am able to import a cutting surface as an IGES file. I should be able to apply thickness to this surface to get a solid, but the IGES file has gone through a DXF conversion first and I think this is effecting the condition of the IGES file. This fits in well with Eric's regarding the hull shape be lock in before before any kind of drawing work begin's. This approach would not manipulate or modify the hull in any way other than to add a thickness component to make it a solid.

It looks like MaxSurf and ProSurf have direct data tranfer with Rhino. I see dollar signs starting to pop up. ProSurf looks affordable. MaxSurf doesn't post a price. If anybody that is following this thread is using either, I would be interested in a simple IGES hull export to see how compatible it is with my current CAD software. Nothing elaborate. Just a simple hullform. Even the default hull that is typically generated with the new model generation.

Suggestions on techniques for hull modeling is welcome also. I'm afraid this statement my be too broad generalities.

 

LP here is a hull I use for a starting point for a yacht hull which was done in maxsurf and exported out in iges. I found it will import into most cad as either nurbs surface or meshed.

 

LP, what 3D software do you have experience with? It appears that many of your comments about current shortcomings of 3D modeling may be a consequence of the software you have used than being true for all 3D software.

My experience with Rhino is that I can section a hull and expect that representation to accurately protray the true hull section, aadjacent parts are truely adjacent, and colinear parts are truely colinear. The accuracy level acheived depends on the care taken in creating the 3D model. (The tolerances that the software uses also need to be set appropriately.) On the molds for a 15 foot boat I was working at to an accuracy of .001 inch. Whether someone considers Rhino at $1000/copy to be moderate cost is up to the individual and their means, etc but Rhino is a bargin compared to other software with equivalent capabilities. Rhino does come with a built in set of easy to use hydrostatics but Orca3D integrates directly into Rhino and provides a full set of hydrostatics analysis and more. (It is also possible to use the analysis commands built into Rhino to determine all the quantaties needed for hydrostatics calculations. Considerably more laborious than adding Orca3D but no additional cost.)

 

LP, I, too, wonder about the sophistication of your 3D software. Your software should be able to let you generate any arbitrary cut through the model--stations, waterlines, buttocks, diagonals and through any arbitrary plane, in both 3D and 2D, and in both iges and in dxf formats. Those traces of those cuts should be of an accuracy finer than you can physically measure (less than 0.001"). You should be able to transfer B-splines as splines, or be able to convert them to polylines. Personally, when I want to generate cuts through the model for drawing in AutoCad, I always specify the cuts as polylines in 2D, because all my drawings are with normal linework in 2D. If your 3D software package cannot do these things, then you will have to find one that does, and that might mean spending some extra money.

Eric

 

i am not a professional, but i read some books and completed my own catamaran design via 3D CAD modelling, which was then exported to 2D polylines for full detailing in Autocad - just as eric sponberg has suggested.

From what i have seen, MOST 3D ship modelling software has this capability, even the free software such as freeship etc - you just need to learn how to use the software more completely.

First, Go into a viewing window that is the appropriate view to see the sections, waterlines or buttocks - depending on which type of 2D polyline, b-spline etc you want to export. So bodyplan view to see the sections, or side profile to see the buttocks etc. MAke sure the sections or buttocks etc are VISIBLE on screen by turning them on etc.
Then, goto the menu and find the export polylines etc function and export it to a file format your 2D CAD software will read, i use DXF format.

Most software ive used works in the above similar manner.

 

bhnautika,

Thanks for the file. Would you be able to do the same with a .3dm file? I also have that import ability and would like to check the function of it.

DC and Eric,

The software I was attempting to model in was an early version of TurboCad. The section cuts themselves were not the issue as much as the accuracy of the lofts. If I remember correctly, I couldn't select the sheerplank edge as a guidepath for a guided extrusion for a sheerclamp. The best I remember doing was placing a profile at specific station locations and getting an approximation of a sheerclamp. Midstation locations might have a gap or an overlap. This is all moot now as I don't use the software now except for archived designs.

I currently have two softwares that I am learning. ViaCAD Pro and Alibre PE. I haven't decided about ViaCAD Pro, but I am spending time with it to get a solid feel for it's capabilities. Alibre PE has a lot of potential, but to fully realize it's potential, I need to upgrade to the Professional version. With that being said, if I am to spend that kind of money, I would rather invest in a more standard software like Rhino.

I think that both CAD systems I have now have the tools to create what I want. ViaCAD has the ability to work with skins and develope solid models. Right now, I am having trouble in building a loft or mesh that produces a proper definition of the hull I have produced in Freeship. I have built an XY mesh from vertex points off of the Freeship DXF output. At the keel/stem transition, the XY components become colinear and ViaCAD is squawking over it. A skin loft from either the X or Y components produces some odd skin perturbations. I have to check control points to insure consistency.

With Alibre, I'm approaching the solution differently. I'm trying to develope the hull directly from the Hydro software output. I'm attempting to import a hull skin that can be coverted to a solid and used cut other components and be used as a guide for lofts and extrusions. The accepted formats for this particular option are .igs .sat and .3dm. I want to exhaust these options particularly for a direct Hydro to CAD import before submitting to modeling the hull elsewhere or continuing to work the 2D aspect.