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Learning how to convert from 2D plans to 3D CAD build


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I have been so impressed by the wonderful quality of the CAD builds on this site that I have been trying to teach myself how to convert the 2D plans to 3D in TurboCAD. I've been doing this by using the 2D plans of the longboat on the Cutter Alert based on the Anatomy of the Ship book.

 

I had been using the 2D plans to make the longboat in wood, and that is taking its own course. However, I am stuck in the CAD programming when trying to figure out how to obtain the 3D hull shape from the verticalised sheer plans. So far I have been able to flip the sides and move them together with the horizontal waterlines and body plan to obtain a box, but I can't quite fathom how to form the hull from this point.

 

The instructions for using CAD on this site refer to 2D lofting (as far as I can see), so if anyone can point me in the direction of instructions on how to move to the next step of 3D creation from plans I'd be very grateful.

 

The essential reason for my interest is (1) to be able to continue to do some form of ship building in a practical way while I am travelling (something which I have to do for a very large proportion of my time) and (2) to visualise plans in a new way.

 

Any pointers most welcome for this two-fold 3D novice!

 

Tony

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Hi Tony, Does the software you are using have any surfacing commands like "lofting" or "boundary surface"? Such commands should do the job. The following figures show the process of using the "boundary surface" command in Solidworks to generate the hull form from a set of station lines and some other assisting curves.

post-142-0-49523800-1363308438_thumb.png

post-142-0-97210300-1363308439_thumb.png

post-142-0-45346500-1363308441_thumb.png

Edited by ppddry
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Tony,

 

What version TurboCad do you have? I have V17. The manual implies that lofting is only available in the TurboCad Pro (read $600.00) version.

 

I believe you can get the information you need without surfacing. But I'm only beginning to learn the ins and outs of TurboCad and its relationship to developing ship's plans. So I'll be watching what you learn.

 

BTW, have you looked at Wayne Kempson's article "Drafting Ship's Plans in CAD" in the articles/downloads section? I've been following that and it's very helpful.

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Thanks, Jingyang. I can render and shade surfaces of enclosed spaces. What I'm stuck on is how to get the 'assisting curves' stage you show in your first picture. Attached is where I am so far.

 

I can then make the keel, stem and stern with no problem. Oh, and I've just noticed from my own picture that I've put the stern section at the wrong station line. Still, you'll get the idea!

 

I can't quite figure out how to mould the sides of the sheer plan to the central line of cross sections. I reckon it must have something to do with tracing the waterlines from the half breadth plan as those are the lines that I can see on your first picture but I still haven't attempted that. However, now I've seen your pictures I'll have a bash later today.

 

Also I don't understand what the top curved line over the boat on the body sections represents in the plans since it is an open boat.

 

Thanks also 'capnharv2'. Yes, I've studied Kemp's article but it presumes you're using the CAD to generate plans from which to make a wooden model. It doesn't go into the 3D creation. I'm using TurboCAD Pro 18 which I got by chance for almost nothing from a friend who gave up on it. As you can see it has the rendering facilities, but I thought all versions of TurboCAD had them as well.

 

Thanks again for so much help so quickly!

 

Tony

post-229-0-77325000-1363346138_thumb.jpg

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Hi Tony,

 

TurboCAD is not the best software for producing a 3D hull.  In Pro there is a lofting function that I have used to create a hull or two from the waterlines, but there is a bit of a problem sometimes due to the logic of the lofting function.  This becomes especially problematic when trying to shell the hull.  In Deluxe, you can use the prism tool and a close set of waterlines to approximate a smooth hull.  Again, TC is not the best tool for creating a hull.

 

Here is a launch I did in Deluxe with the prism tool.  You can see the hull is not smooth.

 

post-24-0-30757400-1363359538.jpg

 

post-24-0-24191600-1363359560.jpg

 

And just for fun, here is the hull of Euryalus.  You can see some of the limitations that adhere to my skill level and, to a certain extent, to TC.

 

post-24-0-02388900-1363359874_thumb.jpg

 

post-24-0-60508600-1363359917_thumb.jpg

 

post-24-0-20164500-1363360002_thumb.jpg

 

One of the problems you may have with TC is the size of the files.  If you are using a 32-bit program (which I think v18 is) then the render times can become quite long.  I have been using TC19 Pro 64-bit and the render times are significantly faster.

 

Wayne

Edited by wrkempson
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Wayne, that's still pretty cool. I reckon I can approximate this with a series of 3D polygons, which I guess are prisms. Anyway, I'll have a bash. Your suggestions and your pictures have given me much encouragement -- I especially like the boat as that gives me an idea of what I should be aiming for. I'll have fewer seats and no cannon on mine, though!

 

Thanks very much

 

Tony

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Wayne,

 

I have to talk with you sometime. You're doing what I've been trying to do in TC for a couple of months, and thought I hit a dead end. Now I think I'm at my wit's end :P.

 

Are there any good TC tutorials out there? I've been using the manual and it hasn't been of much help. Complicating it that I've used CATIA for the past 20 years (and CADAM before that-and Computervision CADDS3 before that). So I'm used to building something in 3-D in a (seemingly) very different way than TC.

 

I would appreciate any suggestions you have.

 

Thanks,

 

Harvey

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There is a lot of videos on YouTube for TurboCAD. The ones by Paul Tracey gave me the initial kick-start for the 3D side. His list of free training videos can be found if you click here. They are very easy to follow and they certainly eased the learning curve.

 

In terms of the manual, I agree the web links can be confusing. The pdf version is a little easier to navigate. You can choose to read the pdf version if you go to 'General' in the 'Options' tab and choose 'Use offline help' in the menu.

 

I've also just downloaded the free version of SketchUp. This is a very much simpler programme to get the hang of, more intuitive and has a much cleaner and nicer interface. Although SketchUp clearly does not have quite the range of TurboCAD, you'll see from the modelling done on the site with SketchUp is quite fantastic. The only limitation I have found so far in experimenting with SketchUp is that you can't load pdf files into it. You'd have to convert pdf to jpeg for importing (unless someone more knowledgeable tells us otherwise).

 

So my advice would be that if you feel TurbCAD is too much, switch to SketchUp for an easier ride which may well give the same results. As for me, I'm still undecided -- having invested so much time in learning TurboCAD!

 

Looking forward to anything you produce in any programme,

 

Tony

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Harvey, as already mentioned TC is not the best program for creating a ship's hull.  Mine is the result of a lot of frustration and a number of work arounds.  Especially frustrating is the stern.  But, if you are going to keep going in TC, I used beziers for the waterlines and then lofted the hull using them.  The key is to make sure all the beziers have the same number of nodes.  Shelling will be a problem at any rate.

 

There is a very helpful forum for TC users at forums.turbocad.com where this topic has been discussed at length.  Just do a search (in the box in the upper right corner) on "hull" and you will find quite a lot.

 

My experience with 3D software is confined to TC (with only a glance at Sketchup and a frustrating trial offer with Alibre and AutoCad).  Thus, it really pains me to say TC is limited in this area.  It is a very robust program for the money, in my untrained opinion.  I think the 3D model with the keel, frames and deck timbers shows that.

 

Tony, keep at it.  You just might be the person who makes a simpler hull in TC!

 

Wayne

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I second Wayne's comment about nodes. At first I was tempted to use too many as it is so easy just to follow the path and click. But the trick of a smooth outline is to use as few as is possible -- two if possible (one at either end).

 

As for being the first person to make a simpler hull in TC, I've already done that. The only trouble is that it's not quite watertight as it has no planks. Still, Wayne's right -- you only get there by sticking at it.

 

Tony

 

The key is to make sure all the beziers have the same number of nodes.

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One point that needs to be made to those of you considering Sketchup is that the program, as downloaded, does not have the tools to work efficiently with curved surfaces.  However, there are a number of plugins that can be downloaded separately to help with this.  Curviloft is a package that includes a few different types of lofting tools.  Joint Push Pull is another package that includes a few different tools to extrude a curved surface out (to give thickness to planking, for example).  Finally, bezierspline is a set of tools that allows you to draw a variety of splines and curved lines.  In general, any plugin authored by Fredo6 (including the three I've just listed) tends to be very useful.

 

A list of plugins, including a number of rendering options, can be found at the Sketchup website here: http://www.sketchup.com/download/plugins.html#ruby

A wide variety of plugins, including a number of drawing tools, can be found here: http://rhin.crai.archi.fr/rld/plugins_sections.php

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Thanks for the links, SketchupModeller. They will be really helpful.

 

At the moment I've been spending an hour or so trying to draw a perpendicular line to a 3D object in TC. I have yet to find the trick. But it'll be there somewhere.

 

Tony

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It's the bottom of the keel, as per the attached picture. It's not that I don't have a work around, since I can draw lines on the plane to which I can attach the keel. It's more that I want to find out how to put in a centre line in order to align it with the keel line I have made on the drawing.

 

For some reason, even though I try to make the workplane conform to the facet (highlighted in the drawing) I can't get a line tool or a perpendicular line to work as I would wish in relation to the drawing. I would point out that the lines are exploded and not part of any group.

 

You'll notice that in this drawing the stem has multiple nodes. I'm correcting this in a new version. Also ignore the keel on the section that is lying across the keel at the bow, since that was there only for alignment purposes.

 

Thanks, though, for looking! Any suggestions welcome.

 

Tony

post-229-0-47726600-1363444713_thumb.jpg

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I take it that the 3D is an extrusion of the keel outline.  Here I have extruded the first keel timber for Euryalus.  The outline is in red, the extrusion is in black.  I then make the bottom facet of the extrusion the workplane.  Then, using a Middle Snap, I snapped a line to the middle of the forward extruded line and the middle of the after extruded line.  This line is in blue.  Is this what you are after?

 

post-24-0-63297600-1363447614_thumb.jpg

 

Wayne

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Yes, indeed that's it. And it works fine for lines. The only trouble is that when I try to do exactly the same with a perpendicular, the supposed perpendicular falls away at a variety of degrees depending on the position of the mouse instead of to the opposite surface and it doesn't snap to anything except to the start point. The object itself as a whole is at right angles to the world view plane and is on that plane.

 

However, your drawing showed me the obvious solution -- just to draw a line down the middle of the beam using the M snap. This has solved the problem I was faced with.

 

So it's like a lot of things. It's an oddity, but luckily I have two good workarounds now!

 

If you know what I'm doing wrong, then of course I'd be glad to know. However I would hate to have you bothered by ferreting around when it's now no longer a problem.

 

Thanks a lot for the help and encouragement, as well as for solving my problem!

 

Tony

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Tony, Wayne,

 

I apologize for getting back to you guys so late. I appreciate your comments.

 

Tony, I'll look into the Paul Tracey videos. I searched for TC tutorial videos a few months ago and could only find pay sites-and I'm cheap! So thanks for the link.

 

Wayne,  I've heard more good than bad about Turbocad(in general), and I paid for the basic application, so I want to learn it. It's plenty useful for other drafting/drawing jobs around the house (although it's still easier for me to just grab pencil and paper at this time). I tried Sketchup a few months ago, but I had a compatability problem with it on my computer, so I had to take it off. I went to the TC forums, but didn't search deep enough. I'll do that.

 

Thanks again for your help and encouragement.

 

Harvey

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I have found on the web a wonderful tutorial called 'LOFTING TUTORIAL: A ship hull in 3d' which you can download as a pdf file and which answers perfectly how to use TurboCAD to loft frames.

 

I hadn't realised there was a function called 'lofting', but of course the moment I found it, a whole host of answers to my problem came at once. Thus 'prisms' are part of the lofting function. They all let you link different planes and points.

 

Sorry if this is incredibly obvious to CAD users, but I'm posting this in case it's of any use to others who like me are starting up in the world of CAD lofting.

 

Tony

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Tony,

 

I'd worked on various CAD systems for 30+ years-none of this was obvious to me :huh:

 

I find that, as I get older, that my mind becomes more "brittle". It's harder for me to pick up on something new-like a new (to me) tool like TurboCad.

 

Thanks for posting that that link.

 

Harvey

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