CAD

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I know there are a few CAD users on here and I'd love to get some info on it. I have no experience with CAD but keep thinking that I should dive in as it sounds like you can do some great things with it. I can imagine lots of applications in my life where it could come in handy but at the moment I've been playing around with designing my own canoes and am looking for anything that could help in that process. I like the thought of using it to design thwarts, seats, deck plates, etc as well. I've also read of people importing the entire hull into CAD after the design is complete for the final fairing and shaping of the forms before printing.

I guess I'm looking for a little CAD sales pitch. What can it do that can't be done easily with other software? What's it good for? What's it not good for? Specific software recommendations? What's the learning curve like?

Thanks,

Alan
 
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Hey Alan, I've been using CAD (both 2D and 3D) for a very long time, but have also drafted the old school way too. You know, drafting board and t square type stuff.
Anyways, I'll write up a blurb and post, but it may not be until tonight
 
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CAD might be a good application for designing canoes. They can be represented by equations with gradual curves.
I used it in landscape architecture school for a year and absolutely hated it. Taking the sweep of the arm in complex curves and putting it through a key board made me crazy. I quit and started my last career at age 50 as a landscape designer instead of an architect. I made plans for people but did it with a pencil and a drafting board.

edit- Good information here. I would just point out that for a traditional group like most folks here, the dark recesses of autoCAD can be very unrewarding. Some like to embrace modern technology. Some like to build traditional and elegant designs in wood and use a pencil. If you can make "a paddle with an axe", you can draw plans for a canoe with a pencil.
 
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Alan,
I will try to make this as simple and as clear as I can, but please don’t think I’m in any way talking down to any of you…not my intent. There are some of you out there that may have more experience than I do, so please add if you feel you can.

I started out using the drafting table and was introduced to a new thing called AutoCAD R14 way back in the 80’s. Yep, that makes me that old.
Here’s my $0.02 worth…

USES- Let’s talk about what you can do with them. You name it, you can design it. Any and everything can be designed using CAD software. I have designed items as small as a 1/8” O.D gasket up to an entire building. They are obviously very versatile. One of my colleagues even built a 3D model of the Apollo Lunar Module, down to every last fastener. The one item I have not used them for though, is designing a boat. I have never had a need to.

PROGRAMS- There are 2D programs, and 3D programs.
2D drafting is just that…2 dimensions (x, y coordinates). Some programs only have this capability, so if, for example, you were designing a canoe, you would have a top view, side view, end view, and multiple cross sections to detail the item.
3D drafting on the other hand allows you to draw in 3 dimensions (x,y,z coordinates) to develop a model. That model is then “sent” to the 2D paper layout on screen to develop the views that you want. You can still have top, side, end, and section views, but you can also add multiple orientations of your 3D model.
One of the features about a lot of these programs is that they are parametric. Para…what? Parametric is a term used to describe the ability to change a few PARAMETERS (that’s where the name comes from) within a chart or as a variable on screen to adjust the item. As an example, if you changed the length of your canoe from 16’ to 17’, a parameter could be set up so that all of the station molds adjust in spacing, or even the addition of another one. Your length of strips could then also change to accommodate this. In theory, you could just change that one parameter (length of canoe) to have every other part on the boat change to suit it. Pretty powerful stuff.
Among other things, 3D programs have the ability to export the data to other programs for use in rapid prototyping machines, CNC milling machines, injection molding machines, and many more. NASA is developing machines to take into space with them to “3D print” parts in case of failure, instead of carrying multiple spares. All they need is the 3D file in a hard drive.

LEARNING CURVE- One can learn to perform basic functions within a 2D program in a matter of hours This would allow you to draw basic shapes, dimensioning, page layout (so you can print something out or save as a PDF), etc. I would recommend taking a basic course to start with. If you don’t want to take the time or money to do this, then at least invest in a text book for the program you will use. Higher functions will of course require more seat time. A 3D program will take much more time and a great deal of patience to master. I would not recommend anyone learning these programs on their own. I have spent hours and hours trying to figure out a function when all it would take is 2 minutes of an expert’s time to teach me. Programs like Sketch-up are certainly user friendly to learn, but there seems to be a trade-off here. The harder to learn programs, are the ones that are more robust for designing with. There are some models that will fail in some programs that won’t fail in others because there isn’t sufficient mathematical software support built into them. Take a course, and buy a text book. Even better if you can find someone who uses the program regularly to mentor you.

BRANDS- 2D AutoCAD (AutoDesk) comes in many flavours, as well as diet versions of these. It depends on the primary use intended for the program. Inventor (AutoDesk) 3D program is quite robust software that is relatively easy to learn. It also comes in a light version. They have student and demo versions you can download for free to try them out before purchasing. I use AutoCAD lite.
Pro Engineer/Creo (PTC) 3D program is an extremely powerful program, with a heavy engineering bent to it. Large companies like Harley Davidson, Toyota, NASA, and Ping Golf utilize this. Very powerful, but time consuming to learn. I use this one.
Solidworks 3D program is a little bit easier to master than ProE, and seems to be the industry standard for smaller companies. It is very similar in nature to ProE. Lots of consumer products companies have had great success with it. I don’t use this one but have had training courses on it.
Sketch-up 3D program allows you to create a multitude of items. People, places, and things. It seems to be very, very user friendly. It can certainly create 3D models as well as 2D drawings, but it’s exporting abilities are a little cumbersome to get data into another program for use somewhere else. If I’m spending all this time designing and creating, I don’t know about you, but I want to squeeze every last drop of use out of it. It does have a tremendous amount of tools for a free, or nearly free program. Go check out the Halloween costume one expert created for his son. There are lots of tutorials available on line and of course lots of how to books for purchase.
There are many, many more programs out there. I have only mentioned 4 that rolled of the tip of my tongue. Generic CAD programs are in abundance online. Just do google searches, do your research, you may be sorry you did. Just kidding, sort of.

COST- Some are free to download from that interweb thingy. Others will cost you your life savings. As an example, the single license I have for Pro Engineer originally cost me $7500 USD. Pick your jaw up. I could justify it at the time because it was being used every day for business. I wouldn’t do that if it wasn’t for the business. AutoCAD was $3500 USD, but again, a business thing. I have the lite version now which is only $1200 USD. Still a lot for most people. The free programs out there are looking better and better, aren’t they? Maybe you have a friend that is not using their copy of a program??? Whatever you do, just make sure that the intended use or application for the software.

The one thing I have found, is that you will go through a love, tolerate, hate relationship with these programs. Sometimes all at the same time. My biggest issue has always been how to get the software to do what I want it to. I know that I can build something a certain way, but how do I get the software to do the same thing? I have heard many people echo the same frustration. No matter what you buy or download, your biggest investment will always be your time.

Hope this helps,

Momentum
 
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Hard for me to give an accurate answer but I'll give my experience first.

I'm a mechanical engineer and although I'm more interested in more detailed design activities like modeling (the mathematical type) and testing, CAD is major part of my job. I'm lucky enough, or maybe unlucky enough, that I work for a corporation that has dedicated designers. What are these guys and gals? They are more or less our engineering drafting lackeys, for lack of a better term. They are responsible for all the drafting work and print detailing. But really CAD is a useful tool, and I use if for all sorts of geometric calculations as well an integral part of structural design work with finite element codes.

So the long and short of it is it a really good geometric tool for calculating things like areas, volumes, center of mass, etc. It can do that way faster than I could by hand. Also the high end codes, such as CATIA, NX, ProE, etc have sketch driven constraints which, if you know how to use it, is absolutely fabulous... possibly the best and most overlooked engineering tool out there. I can whip up scenarios of very complicated geometry in seconds using that. If one had to the same thing on drafting board, analytically or even with something archaic like AutoCAD, it takes much more time.

Now the disclaimer I see above. The high end codes cost a fortune and are only practical for corporations, and even then I think software companies are the pirates of the modern world. I've used some free ones. Honestly, I'd rather use a pencil and paper. Most are pretty unwieldy and a pain to learn without very much of the functionality you get with a real CAD system. Now I really wonder how much the average woodworker/boatbuilder would use it, but I could definitely see where if you were designing boats being able to calculate volumes and areas of complex shapes would be really useful.

One that I like that used to be somewhat affordable is Solidworks. I've used only the older versions but it was an OK 3D software. I actually think it's easier and less buggy than ProE. I don't like ProE myself - I'm used to NX now and if I had to go to something else I'd choose CATIA.

I find that all these codes are more or less the same. Some have some slightly different functionality but the base is similar. Once you know one, you can pretty much do any of them with a little perseverance.

Seen as how Siemens makes NX, I'd recommend this as something to play with as a 2D code.

http://www.plm.automation.siemens.com/en_us/products/solid-edge/free2d/

I've tried it. It's archaic and kind of a pain to use, but it will help you decide if computer drafting is for you.
 
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Wow, some great information. Thanks! Don't worry about talking to me like I'm stupid, I think that's exactly what I need at this point.

After reading that and hearing about the different software and how some are geared towards specific tasks I wonder if I've already been using CAD software? I guess in my mind "CAD" has always been this mystical software I've heard about but never had explained. I always assumed all CAD programs were pretty similar and that you were basically starting with a blank piece of paper and that things were done manually, similar to drawing lines and shapes with a pen and paper, only on a computer. But it sounds like maybe there can be more "automation" than I thought?

When I designed my house and used Chief Architect software was that just a dumbed down CAD program specifically geared to that task? http://www.homedesignersoftware.com/homedesign/

What about this cabinet design software I've used? http://www.ecabinetsystems.com/

And now that I've been tinkering with boats I'm using Delftship: http://www.delftship.net/DELFTship/index.php/delftship/delftship-free

Are these essentially all CAD programs built for a specific purpose or is there a distinction somewhere?

Perhaps I have everything I need in Delftship for playing around with canoe designs but I've read many references about exporting a hull designed in Delftship into a CAD program (usually Rhinoceros) to run other calculations (like stability) and for final tweaking. But exactly how and why they're going about it I don't know. They're mostly designing things more complex than a canoe but I made me wonder what else I might be able to do and how to go about it.

I know someone locally that used to teach CAD at our community college and is recently retired. Perhaps I should see if he'd be interested in giving me some tutorials.

Alan
 
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Just to clear some things up, it's not really automated per sae. It's more or less higher order functions. It seems to me that every release they need to add some doodad to your screen to make it 'easier' to do something that usually wasn't that hard to do to begin with.

Now if you just want to draw lines and arcs like on a piece of paper, then solid edge will be your guy. There are also things like layers where you can overlay things and turn them on or off. Pretty useful tool. It would be like tracing over a print in the old days but you can do lots of them and copy things over with a click of a button.

The other stuff I consider basic, but you may be thinking automated is things that create 3 dimensional solids like extrudes (takes a 2d area and extends it into a 3d solid along a linear dimension), revolves (takes a 2d area and creates a solid of revolution about a central axis), sweeps (takes a 2d area and extrudes it along a defined guide or set of guides), lofts (creates a 3d solid by interpolating between a set of 2d areas), etc...

Then within those functions there are booleans which allow you to add, subtract, or intersect solids. You can create surfaces, add radii, chamfers, etc, etc, etc... the list goes on.

Once you've created a 3d solid you can rotate it in space and look at any angle you like. You can measure any geometric property you can think of by adding density such mass, mass moment of inertia, center of mass, center of an area, surface areas, volumes, etc, etc, etc... these are pretty useful because it's cumbersome to estimate these by hand or from a 2d drawing.

Then there are ways to create 2d drawings from your 3d solid. You don't have to define every line of a view like old days. The computer can simply extract whatever view you want from your solid model.

And on top of that you can use the math data from 3d solids to define tool cutting paths in CNC machining centers, provide inspection data to CMMs, or perform other higher order analyses such as fluid dynamics, structural analysis or motion simulations.

For management you can create pretty pictures or animations.

Again it's hard to give an accurate answer of what you need without knowing exactly what you are going to be doing. A 3D software will give you infinitely more flexibility in designing something of complex geometry like a boat. It will be much easier to calculate volume, and volume at any roll angle of the craft and do your own stability and load/displacement calculations. You'll also be able to reasonably estimate the weight of the final product.
 
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Again it's hard to give an accurate answer of what you need without knowing exactly what you are going to be doing.

It's hard for me to ask accurate questions as well for the same reasons. :)

I did some digging around and came up with what seems to be a pretty comprehensive (and free) CAD program geared towards hull design (polycad). Downloaded it tonight and have been tinkering a bit. Lots to learn. I was able to import a design I did in Delftship and then use Polycad to start producing some stability graphs that show how much righting force there is at different heel angles. It also shows the underwater hull shape as the boat is heeled as well as showing the swamping point (when the water line reaches the gunwales). This was one of the things I wanted a CAD program to do and having no CAD experience couldn't envision how to make it happen. But it turns out the software is already set up to make those calculations if you just give it a couple inputs. I guess that's one of the things I meant above by "automation."

I still need to figure out how to make it produce the desired number of stations at the correct intervals and to get them faired so I'll keep plugging away at it. Delftship probably gives me all that I need, at least for starters, but for me there's no better way to learn than being in over my head.

If it makes things any clearer I attached some files to show what Delftship looks like and the data it's able to provide. It also does what I guess I'd call 3D modeling of the hull, as well as tons of other things I can't even comprehend. I'm having fun and learning a lot though.

Alan

EDIT: I see after posting that the images display quite small. If you right click to save them and then open in another program you can get a better look.
 

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Looks pretty good. CAD is very generalized, this looks very specialized. Probably better for what you are doing because you don't need the power of CAD and even with that you still would have had to do all those calculations as a post process. I don't know of any big time commercial code that has any specific hull design modules in it, but I could be wrong... it's not an area I'm familiar with.

The only thing I don't like about certain canned packages is there may be built in limitations or errors. I'm not saying big dollar CAD is bug free but more or less that the outputs they give you are usually very well tested and they aren't going to be very specific like that.

I see a lot of bugs or incorrect calculations, or incorrect application of canned engineering software. I've also made and seen a lot of mistakes made by hand calculations or spreadsheets. Take it for what is. I often double check calculations that I deem critical, and that's how I often find errors or limitations.
 
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Delftship is definitely specialized towards hull design but supposedly you can design whatever you want with it, from boats to houses. Polycad seems much more generalized and is giving my brain a good stretch. It seems to have some things, calculations for one, aimed towards boat design but there are all sorts of buttons and commands that are greek to me and unfortunately there's not much in the way of tutorials. Thankfully, so far, the Autocad tutorials I've found, though not being identical, have been a help figuring out what some things are and how to accomplish them.

Good point about possible bugs in the calculations. Thankfully both software packages make the same calculations so I can compare.

Alan
 
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