The Ship Model Forum

Just a quick note to all hands who've been kind enough to lend me a hand, I've downloaded the free DraftSight for individual use, along with their "getting started" lessons. I've also picked up from the library AutoCAD 2004 and AutoCAD LT 2004 by David Frey as well as Just Enough AutoCAD 2007 by George Omura, figuring these would be reasonable approximations to get me off square one until I need a more dedicated manual. I've started playing with DraftSight, so the ball has started rolling, we'll see how productive the long dark winter turns out to be...

Thanks again for your assistance and advice.

Rob, thanks, it's always nice to know that help, tips, and suggestions are readily available. As I'm watching Olympic swimming events right now, it's rather fitting that I simply have to "jump in" myself for at least the first few laps before asking the coaches for pointers...

I think that is one of the nice things about Draftsight, if you want to read up on it, look for ACAD 2004-6 texts. I am mostly self taught on ACAD 2004 using the help file and the forums of the time. I also took a couple classes in community college on the subject. And then I spent a year and a half working for Tim, who taught me more than a few tricks. Feel free to ask questions when you need help and we'll try to help or point you in the right direction.

Leaning toward Draftside (Draftsight?) given what has been said about it, plus the freebie aspect is not to be dismissed. Will also give Blender a test spin. I also checked for accompanying texts, used AutoCAD ones can be picked up for just a few bucks, so even if not the latest edition I figure that would be an additional resource. Haven't checked to see if such are specifically available for Draftside yet, but I gather that what works in one will pretty much work in the other.

MareNostrum wrote: looks as if I may be able to tackle this thing by myself, saving a few hundred bucks in tuition fees!

So which program did you decide to go with? Do tell.

-Dean

Roscoe/Dean- Please, no apologies necessary, I was referring to my manners, or lack thereof, for being slow in expressing my appreciation to everyone for taking the time to get me more familiar with this arm of the hobby. Really, I detected nothing "untoward" in your comments, I don't think the chief of protocol will be taking any action.

We all have our particular CAD packages we like. I am a die hard SolidWorks guy, Phil is dedicated to DesignCAD, and Tim is enamored of ACAD. I have spent the last year using Inventor and I think it is representative of the fact that all CAD packages have good things and then they have things we wish they would do better. I think the important thing is to find one that works well enough for you right now and then spend the time to get really good at it. It takes 10,000 hours of practice to master something and CAD is no different. At that level, the differences in CAD packages are trifles because you have learned workarounds for all the major flaws you don't like. I say pick one and stick to it.

For the record, I have enough hours in both SolidWorks and Inventor to call myself and expert in both, and I would say SolidWorks still easily bests Inv in a number of areas that are key to doing ships (e.g. surfacing, configurations, mates versatility). But I don't have enough time in any other 3D programs to be able to compare them.

MareNostrum,

If it seemed my manners were a bit lacking, my apologies to you, Phil and everyone else. I was just trying to add a bit more insight into some of the differences of the programs mentioned. Although looking back at my response, I could have worded it better.

Take care,
Dean

Phil, Roscoe, Cadman, the Whole Gang, before bad manners get the upper hand, my thanks for all your responses, looks as if I may be able to tackle this thing by myself, saving a few hundred bucks in tuition fees!

Phil,

SolidWorks would fall under a very expensive type 2 program. It uses lines, circles, etc. in what they call sketches, to make the solids or surfaces. There are no primitives in it like some other programs to start from, every solid or surface you make is from a sketch, except when filling an open area between edges with a surface. But it's solid bodies are true solids, not just knitted surfaces, they have actual mass, to which different materials can be applied.

For those who are trying out Blender, check out Blender Swap, tons of free models to download and play with. You do have to register to download, but no biggie, that's free too. http://www.blendswap.com/

-Dean

Dean,

Thanks for the correction abouot Rhino. I haven't used it but know people who have. I wasn't sure if it was a full-fledged type 1 program or type 3. I guess SolidWorks is also a type 1 - a very expensive type 1, but with an extensive set of capabilities.

Mare Nostrum,

Some programs allow you to import a bitmap image, and some allow you to scan images into the program, but this is not common to all programs. I have a friend who uses AutoCAD and at least a few years ago it couldn't import bitmaps. I don't know about the latest versions. The DesignCAD program I use will work with bitmaps. It has a autotrace function, but like everu other autotrace program I have seen it is almost worthless. You can manually trace over bitmaps but this is a bit tricky.

You should remember one very important thing - there is little compatability between CAD programs. You can transfer simple things like lines and such, but colors and material properties may be lost in the translation. Further, each program has it's unique way of representing 3D objects and they may become scrambled in translation. Once you start using a program you may have to abandon everything you have done if you want to switch to another program. At best, after you translate program A's files for use on program B you will have to do a lot of cleanup work.

Phil

rtwpsom2 wrote:Ask Tim what I was able to do with that.

Rob, my minions still marvel at the fully rendered 3D solid models with realistic textures that you created while you worked with me. Most of the early work that became the Dragon Buchanan was done in AutoCAD 04. I still laugh when the salesmen call and argue with me that AutoCAD is not a 3D program. You just need to know how to use it.

I'm with Rob about Draftside, it's free, and basically an AutoCAD clone, so there's no investment to make. Plus that training course (if you decide to take it) will translate almost to the tee. I use it to tweak laser cut files before I send them out, basically converting splines to polylines, which the laser likes much better.

Like any CAD program though, it won't "fill in the blanks" of missing geometry, but can be used to best guesstimate what you don't have, so some "eyeballing" will still be used. And going off of vague drawings and pictures just compounds that. There is no magic wand CAD that I know of.

-Dean

Many thanks for all your replies and suggestions, sure is a wealth of information in all that. Let me pass on why I'm interested in these programs: there are model subjects, both ships and aircraft, that most likely will never be kitted, or for which not especially good plans exist, if they exist at all, which means scratchbuilding them will have to be the way to go if I want a model. When I say plans are not especially good, by that I mean generally the length and width dimensions are provided in side views and top/bottom views, but cross-sections for either bulkheads or frames can be quite sparse, leaving a lot of guesswork to extrapolate (or is that "interpolate"?) what the missing sections would look like. I figure that an AutoCAD-like program would allow for accurate calculation and depiction of what those missing frames would look like, and I can then be off and running.

In a somewhat related way, I am guessing that AutoCAD and its kin would allow one to scan a photograph of a subject for which there may only be the most basic of dimensions available, but by plugging those in, and then translating certain coordinate points from the photograph into the software, one can then follow contours and get other dimensions, again from which to lay out a good working plan to scratchbuild the model. This would be somewhat like working off a set of incomplete plans, only one or two steps back, having an image but then relying on the software to do the number crunching to give final dimensions, shapes, and to maintain proportions, better than "eyeballing" it.

Just a note to chime in from a diehard SolidWorks user, Solidworks has released a free program called Draftsight which is a clone of AutoCAD 2004(ish). All the commands and tools from ACAD '04 work the same in Draftsight and it saves in native dwg formats from r12 to r2010. It will also open all existing versions of dwg files. The main reason that I like it so much (besides the free part) was because I thought 2004 was the best version of AutoCAD. It was the easiest to use and customize, had the most functionality, and was pretty fast. It also introduced me to 3D with it's limited 3D and rendering functionality. Ask Tim what I was able to do with that. If anyone wants to do 2D and basic 3D I would encourage you to go to http://www.3ds.com/products/draftsight/overview/ and download it. It's only 76 mb's and works on a lot of older computers.

Phil makes a good point, every program is somewhat different, but the type 1 programs like he mentioned, will have similar functions when it comes to drawing lines, circles, arcs etc., that's where that training will come in handy.

The Solid modeling/parametric programs still use those same principles (lines, arcs, etc.) to make the solid bodies, but with extra features to link those items and/or solids so that by changing one dimension, it'll change other features of the part or assembly along with it. It can get very deep and sometimes frustrating when it comes to using those type of functions, you need to plan carefully. And they usually have a decent rendering program included.

Now with Blender, Silo, Truespace, etc., these programs are geared towards freeform 3D modeling, more for making it look right, not necessarily correct dimension wise. It can be done, but it's more like tweaking vertices, edges and surfaces to get the shape you want. There is much more to it than that of course, and there are more options when it comes to rendering.

So depending on what you want to do, I would look into the type of program that suites your desired outcome and start there.

And Phil, Rhino should be in the Type 1 list.

Good luck,
Dean

There are three basic types of 3D CAD programs:

Type 1. Basic 2D/3D CAD programs. You create things like in a machine shop. When you drill a hole it is done and you can't change it. You can also construct solids surface by surface and then combine them to create a solid. Once created the surfaces no longer exist as separate entities. This is the way AutoCAD and DesignCAD work. They are more for creating precision designs with basic 3D images, 2D drawings of 3D objects, NC machine control and 3D Stereolith. They have limited rendering capability - just enough to allow you to visualize the design with basic options like shadows and multiple lights.

These programs have a complete 2D drawing set, and have a "paper space" mode that generates 2D images from 3D designs. This is useful when you need a paper drawing of the 3D design.

You can get add-on packages or export designs to high level rendering packages, but it isn't a simple process. The more expensive programs have fairly complete rendering features built in, but they are not as complete as the Type 3 programs mentioned below.

The AutoCAD course should be a good introduction to this type of program.

Type 2. Parametric programs are very different critters. Virtually everything is dynamic. After you have created a hole you can change the radius and the program regenerates it. Virtual "solids" can be constructed from intersecting surfaces, and if you change the surfaces the solids change. These programs are very useful for designs that will change over and over. It is much easier to rework an existing design than in the type 1 programs.

I'm not sure how well the AutoCAD course would be as an introduction to parametric design.

Type 3. The third type of 3D program is more of an illustration program for creating pretty pictures. These have high level rendering capability using ray tracing and other algorithms for creating reflections and such. They have pretty limited capabilities for engineering design (NC machine control, 2D drawing, etc.) but many can generate 3D stereolith files (STL) for 3D printers. Blender and Rhino are examples.

****

No one program has every feature found in all programs. You need to decide what you want to do and pick a program that will do it.

No two programs have the same feature set or even similar user interfaces, so the AutoCAD course will not solve the problem of having to learn an entire new way to operate the program if you end up using something other than AutoCAD.

Some people use a basic CAD program like DesignCAD or AutoCAd to create a 3D design and then export the design to a rendering program to generate realistic images.

Finally, 3D design is very different from 2D design. If the autoCAD course is just an introduction to the program for 2D drafting, with little emphasis on 3D design, it won't help you much for learning 3D design.

The best way to learn is by doing, and no one but you can teach you this.

Phil

AutoCAD is still the industry standard. There are many differences in it and Solidworks and the other competitors. But the concepts are the same.

I've been following the threads on the different CAD programs and finding the discussions helpful, but one thing that concerns me is the learning curve. As I'm one who learns better in the formal classroom setting than by self-teaching when it comes to something rather involved such as CAD programming, I've found that the nearby community college offers an intro to AutoCAD ("This course is a first course in computer aided drafting including an introduction to AutoCAD, drawing, editing drawings, applications, using advanced functions, producing hard copy and customizing AutoCAD. The emphasis of this course is in developing drafting techniques using the computer as the drafting tool. Specific topics include system set up, 2-D drawing, editing drawings, multi-view, drawing, orthographic views, dimensioning, sectional views, and graphic patterns").

My question is this: would a course in AutoCAD provide a good universal basis to use just about any of the programs mentioned in this forum (e.g., Blender, DesignCAD, ModelCAD, etc.) that some seem to find particularly suitable for their modeling, or is training in AutoCAD more program-specific? In other words, if you learn how to drive one car with a manual transmission, you can pretty much drive any other car with one (the shift patterns may vary a bit), so does the same apply here? Your thoughts appreciated.

Tea Monster,
many thanks for the link, exactly what I need.
cheers all for your help.