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 Post subject: Re: Free CAD Program
PostPosted: Sat Jun 18, 2011 9:08 pm 
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I am slowly chipping away at this software. The learning curve is steep (almost vertical!) and I have only 10 more days on my "free trial" before making a decision on whether to fork the $100 or not. That said, I have been able to make some simple shapes, though I'm still not sure how to manipulate them.

One point of frustration is that to really learn the software I get the idea you have to buy the tutorial CD. Obviously, I don't want to do that until I'm sure I want the package - something I am leaning toward, by the way.

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 Post subject: Re: Free CAD Program
PostPosted: Sun Jun 19, 2011 3:51 pm 
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Location: Corvallis, Oregon, USA
noplate,

You can find a tutorial here for an older version:

http://forum.designcadcommunity.com/ind ... 5#msg17575

The basic 3D design procedures haven't changed. Some new features have been added since this was written, but the general ideas you need are there.

The problem I have with tutorials is that they tell you how to do something you really aren't interested in, and don't tell you how to solve your particular problem. If you want to know how to do something specific, just ask on the Forum. Also, look through the "Tips and Tricks" section for a random assortment of problem solutions.

IMSI has kept the price of DesignCAD low - very low compared to everything else on the market. Consequently they don't put a lot of cash into the tutorials. What is available goes into adding features requested by users and fixing the inevitable bugs that pop up, especially when Microsoft changes something that breaks the program.

It is a steep learning curve - I have been there, back when the program didn't work as well as it does today. But if you keep at it suddenly one day satori! You understand the program and you know what you are doing. The only way to learn is by doing.

Phil

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 Post subject: Re: Free CAD Program
PostPosted: Mon Jun 20, 2011 7:24 am 
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Here are two surveys -- CAD popularity contests. One samples rc (primarily aircraft) CAD modelers, another CAD boat designers and modelers.

http://www.rcgroups.com/forums/showthread.php?t=1175257

http://www.boatdesign.net/forums/design ... 31058.html

In reading over the rcgroups poll, note that there are several variants and generations of widely used programs like AutoCAD and TurboCAD. To get an overview, pencil up totals for all the different AutoCADs, all the different TurboCADs, and all the different DesignCADs. Six program types account for 71% of the usage, as follows: AutoDesk (all AutoCADs, Inventor, etc), 24%; Solidworks (including 2D, etc., 19%; Rhino3D, 11%; SketchUp, 9%; the many TurboCADs 7%; and the DesignCADs, 2%. The remaining 29% of the votes are widely scattered across many different programs.

The most commonly used programs are AutoCAD and Solidworks. Vastly expensive seats -- but free to the people who use them, because they have access to them at work. Similarly, in the boat CAD hull design survey, several of the programs cited are specialized professional packages dedicated to hull design. The respondents have free access to these programs at work.

Independent hobbiests probably gravitate to Google Sketchup, which is literally free, and TurboCAD and DesignCAD. If you are a student or have a student in your family, you can purchase CAD software, including full featured Rhino3D, at pretty reasonable prices. I learned this morning of another free 3D, possibly intended as a rival to Sketchup, this one from Autodesk:

http://www.123dapp.com/about

In general, be a little careful with norminally free CAD software, since some of it turns into a pumpkin at midnight some months hence. Read the fine print, is all.

I have used DesignCAD3D (a prehistoric DOS version with a BASIC language scripting feature -- loved this). TurboCAD, AutoCAD and Rhino3D.

TurboCAD is cheap and many people swear by it but I was never able to "get it." To me, the value of its very low cost was that I didn't feel bad about abandoning it in the search for something I could actually learn to use.

The one I use everyday is Rhino3D. If I had it to do over again in 2011, I would probably start with Google Sketchup (free, with plenty of free video tutorials and a well established support group online to learn from). Then, with basic skills in hand, try out some free trial downloads for various commercial CAD programs.

Nothing is wasted. What you learn in one program language will apply, sometimes very directly, in another program.

There is no best program, although there are best choices for specific design jobs.

I found Rhino3D to be the easiest to pick up, but I was coming from AutoCAD, and Rhino was originally an AutoCAD plugin, so the commands are similar. I was a student so Rhino was very reasonably priced.

CAD isn't drawing. It is programming a computer to draw something. You don't draw a circle. You type the command word, Circle, plus an origin and a radius -- and a circle appears.

Learning CAD means learning to use a programming language: entering command words or touching a succession of command icons. If you learn 20 or 25 basic command words of any one CAD language, plus "snaps", you'll begin to have a feel for doing CAD. At that point you can start evaluating different trial programs. At the basic level they all do the same thing using slightly different commands.

Michael


Last edited by mcg on Tue Jun 21, 2011 6:39 pm, edited 2 times in total.

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 Post subject: Re: Free CAD Program
PostPosted: Tue Jun 21, 2011 12:05 am 
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Location: Corvallis, Oregon, USA
Michael,

I do not want to be too argumentative - and I do agree with what you say. But, if you are using a program that requires you to type "Circle" and then type in an origin and radius you are working in the dark ages. You might as well be drawing with a hammer and chisel in stone.

AutoCAD worked that way in the 1980s and that is why my company dumped it and switched to ProDesign - now DesignCAD. To draw a circle you press "O," then click a mouse button to set the center, then click again to set the radius. You can left click to set a point at the cursor or right click to "gravity snap" to an existing object. If you want to set a specific coordinate for a point you can set absolute XYZ coordinates, relative coordinates, or polar coordinates. But in most cases all this extra typing is unnecessary. DesignCAD has seven different ways to draw a circle.

Every key stroke, mouse movement or mouse click is work. I rate programs by how much work you must do to accomplish a task. Using your example, typing "circle" and then two sets of coordinates (in 4 place precision) could take as many as 20 or more keystrokes to accomplish a single task. In DesignCAD it would take only three actions: "O", click, click. That is 1/6 as much work to accomplish the same task!

DesignCAD commands can be executed in five ways, depending upon how you like to work (and not how some programmer decided you should work). You can enter commands on a command line as you mentioned, or open a menu, or click on a command icon in a toolbox, or just press a key. And if you want you can record a multiple command sequence as a macro command and then assign it to a key combination - or to an icon in a custom toolbox. You can also create very complex macro commands with a basic-like macro command language. It is this extreme flexibility that allows an experienced user to customize the program to get work done very quickly.

This is why I like DesignCAD. It has the only intelligently designed user interface I have seen in existing CAD programs. After using it for several hours you expend much less work to accomplish a task, and get the job done faster. For me this is far more important than some of the esoteric features of more expensive programs.

I have worked with people who are very experienced users of other CAD programs, and I have been surprised at the lengthy rituals they must go through to get those programs to do even simple tasks. At least they are pretty simple in DesignCAD.

As you said, most programs have a full set of features for CAD design. But they are not all easy to use. Even if they are free they may not be much of a bargain!

Phil

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 Post subject: Re: Free CAD Program
PostPosted: Tue Jun 21, 2011 12:40 pm 
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Hello Phil,

Actually I did not say typing the command word “circle” was the only available method for putting a circle on the screen. In any contemporary CAD program there are many quick and quicker ways to communicate a command to the computer. We could do a circle with 3 clicks.

My point was that the word “Circle” is in fact a word you can type -- a verbal command. Command words are elements of a command language. Learning CAD is learning a command language. However you choose to enter a command, it is a word.

Learning to enter the right command words isn’t the same thing as learning to sketch. People come to CAD with an artistic impulse – they want to draw something. It leads to frustration.

You want to draw the dreadnought? Great. Here’s a command dictionary (thump) to get you started.

A completely free program like Sketchup (as opposed to any free trial program) is perfect for beginners because it has no deadline. You can take as much time as you need to learn a basic CAD command language. Free Sketchup is by now a mass movement. There is a fat catalog of free tutorials on YouTube. If you are just getting started – and necessarily struggling to identify and memorize the first 20 odd essential words of a new CAD language -- why pay more than $0.00?

IMHO the Free trial downloads have a different purpose. If you already know a CAD program, a free trial is a good way to take a look at competing or more advanced CAD programs.

Michael


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 Post subject: Re: Free CAD Program
PostPosted: Wed Jun 22, 2011 1:06 am 
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Location: Corvallis, Oregon, USA
Michael,

You are right. Sorry for preaching!

Your point about wanting to be creative and having to beg the damned program to do what you want is right on. It is frustrating trying to learn the new "language" that any program understands.

You are also right about free trials. They are an obvious attempt to "set the hook" and get the user to buy the program later. Most are good for 30 days and you really can't learn much about any program in that time.

Maybe the most important thing is whether you have free, unlimited help available. If the sleazeballs want to charge you for answering help questions, or for access to user forums, avoid the program!

Phil

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 Post subject: Re: Free CAD Program
PostPosted: Wed Jun 22, 2011 4:43 pm 
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If you were teaching CAD 101, what would be be 1st day of class command set? Those commands that will be used constantly and have to become second nature? In my program I would guess maybe: line, move, copy, mirror, trim, delete and for fun of it, offset and revolve. These commands, or something very like them, must be common to a lot of CAD programs. Before things progressed very far, and to make these commands useful, it would be necessary to show How to Select stuff, and to introduce snaps.


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 Post subject: Re: Free CAD Program
PostPosted: Thu Jun 23, 2011 1:49 am 
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Michael,

That is a good question. I would take an entirely different approach.

First I would consider the things you need to do to set up the program for the type of drawing you want to make, 2D or 3D. This would be things common to both types of drawings. Then I would tell how to get different views, move the cursor to specific points, save files, print, etc.

Then I would discuss what it is you are trying to do. 2D and 3D CAD are entirely different in this respect. This is a real problem because there is very little in common between creating a 2D drawing and a 3D object. In fact, what you learn about 2D drawing can become a real handicap for learning how to work in 3D. I see this with almost every newbie on the DesignCAD Forum who is trying to learn to use the 3D features. If someone wants to work in 3D only I wouldn't even mention 2D drawing until after the 3D techniques are mastered.

In 2D CAD you are basically creating a drawing on virtual paper. Most people already have some idea of how to do this with a pencil and an eraser, so they just need to know how to use the program to draw lines and curves, basic geometric shapes, etc. Then the basic line editing functions would be introduced, like intersections, trimming, mirroring, rotating, etc.

With 3D CAD you are creating virtual objects, almost like working in a virtual machine shop or sheet metal shop. Almost every 2D "drawing" technique that you have learned is useless in 3D. So the first thing to do is get people to think in 3D, and not 2D. Show how to move around and view your work in 3D space. Then introduce 3D construction techniques (additive and subtractive). Then explain how to create the basic solids and edit them (solid Boolean operations). After that show how to disassemble solids and reassemble them. Then explain how to create solids from individual surfaces.

Phil

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 Post subject: Re: Free CAD Program
PostPosted: Fri Jul 01, 2011 9:24 pm 
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I don't know that these programs would be up to what users in this forum would expect, but when it comes to really free CAD software (as in "don't have to pay at all for the full version, ever") the options I know of for 3D modeling are:

BRL-CAD
http://brlcad.org

This program has a steep learning curve and a rather different style of modeling and working compared to most other CAD programs, but it is freely available and actively developed.

Ayam
http://ayam.sourceforge.net/ayam.html

Not a true "CAD" system but it works with NURBS primitives, which are what most modern CAD systems understad - may be useful.

FreeCAD
https://sourceforge.net/apps/mediawiki/ ... =Main_Page

This one will look more like what you would expect from a CAD system, but is still in early stages.

For 2D, you might try LibreCAD http://librecad.org/cms/home/features.html


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