Thoughts on CAD

[toastydeath]

Toasty, the whole point of these newer 3D cad programs is for designing equipment from start to finish, thats what they excel at. You might sketch out an idea on a napkin but the whole design is done in the cad program. The Boeing 777 was designed on one from start to finish, no paper and pencils or other methods and sent to production without any mock ups or other preproduction work, it's to expensive to do that anymore.

I am just conveying my experience in a production environment with SW, regardless of the what advertised point of the program is.

My own experience and other people I've spoken with in other companies, solid modeling is not the space to be working out the top level design of something in most applications. It's possible, but it's cost prohibitive for many businesses from a time standpoint. I have heard of more people at home doing this than I have businesses, because hobbyist time is relatively cheap compared to an hour of time for an engineer.

Feel free to disagree with your own experiences, but that's my position on the current state of solid modeling no matter what they claim on the box.

[Stepside]

I would have to say this has been a discussion where I agree with most everyone. It boils down to what you want to get done, how you approach a problem, how much you want to learn as well as available funds and output devices with their needs/requirements.

I just finished a lighting device for our kitchen--sketch on the back of an envelope and a rendered Rhino drawing for the wife. built it from the sketch.

Needed some cams for a mechanical timing device--draw in Rhino as a 2-D drawing and sent to the laser engraver for acrylic parts.

Building a Side Lever Steam Engine from HSM ---draw 3-D metric in CAD insert it in a "inch" drawing and scale 1-1/2 to 1. Then adjust fasteners to fit the enlarged model and machine with RhinoCam.

Building some machine parts for an important customer -- redrew his drawing with CAD to find his error and then machined part on a manual Bridgeport.

Drew a 3-D drawing of a foundry pattern-- had it printed with a 3-D powder printer and sealed it with epoxy resin and painted. Rammed up the pattern in green sand and cast in aluminum.

My point being -- Use what you have to solve your problem with the ammount of effort you wish to expend. There are a multitude of different software programs available but they are just tools just like the lathes, milling machines, welding sets ect.

So play safe and play often.

[oldtiffie]

Where's my caddie?

There are a lot of "problems" that some have with geometry and trigonometry as well as "shop math" that can be solved very quickly and intuitively with the simplest of CAD systems.

Solving for settings, angles or sizes are pretty quick and easy as well as giving you a very quick visual picture of everything without any (or not too much) formal "math".

Angles for off-sets for taper turning is a prime example. So is sketching for a "3-wire" thread measuring set-up where the formulae and variables in the tables that come with the "3-wire"set can be a real PITA and "slips" too easily made. Just sketch it in CAD and extract the sizes/dimensions you want from the sketch.

Very quick assembly sketches can be made to ether see that - or how - part do (or don't) fit together - or what options you have to make of fit something in an assembly.

This is the electronic basic "back of an envelope" stuff.

All too often all that is needed is a "2-D" sketch/concept without dimensions at all as they can be "picked off" as and if required.

Many associate it with being an electronic "drawing board" (which in many cases it is - but not always) which suggests a fully formal drawing. I use it as I would a bit of paper in the shop.

But I can sketch faster and better by hand in most cases.

That is all going to change when I have to "get my finger out" when I start delving into CNC!!!

[BillH]

This is for hobby, for my own pleasure. To me, the whole point of using CAD is so I don't need to use a pencil and paper.

[lazlo]

+1 Bill. Once you get hooked on 3D assemblies, you'll never go back

Like Bill, Toasty, and others have said, the interface and creation flow on SolidWorks is superb -- it's really is like virtual machining of the part.

[gellfex]

I'm with the "no pencil & paper" crowd. I've used Designcad for 18 years, played quite a bit with Solidworks and currently am a fan of Sketchup. What I like about Designcad and sketchup is that I can design the way I think. Stretch a piece here, or there. move this feature, scale down that. While Solidworks was amazing I found the workflow of design clunky for me. If I was doing a part for a production run, there no doubt it's superior, but even costs aside, it wasn't my favorite.

I still use Designcad for 2D sketching, but have moved most of my 3D to sketchup. There's certain ways in Sketchup to emulate some of SW parametric features by using the "component" and mirroring commands.

[Nick Carter]

I love Rhino, best piece of software I've ever bought.
One of the great things is their newsgroup. If you ask an question, even a stupid one, you'll get a bunch of helpful answers. Support is very important.
There are usually multiple ways to do the same thing in Rhino, which means that you can develop a workflow that is comfortable for you.

[3jaw]

I'm a big fan of AutoCAD but I must admit that I haven't used any of the other CAD packages so I don't have anything to compare it to. At one place I worked we used AutoCAD solids to design checking fixtures for automotive components. We did not have parametric solids so changes were a little bit of a pain (you get used to it though).

I feel the real secret to AutoCAD is to learn to draw using the command line instead of trying to use the menus. I can fly through and design a simple part almost as fast as I could freehand sketch it with pencil and paper. My left hand is typing commands and my right is driving the mouse.

Somenone complained earlier that they had to know beforehand what the length of a line had to be. Not so, the "OFFSET" command is your best friend and can be invoked simply by typing in the letter "o", enter the offset distance, pick the entity that you want offset and the side you want it on, and voila'. This is just one example of many shortcuts that can be used in AutoCAD that can speed up the design process.

I guess the point to this whole thread is to find a CAD package that works for you and you are comfortable with. I don't think there is an absolute "Best" CAD program that works for everyone.

Greg

[Bruce Griffing]

I'm interested in Rhino, but don't want to bother with the download trial if it does not meet some basic reqirements. These are difficult to discern from their website. Does Rhino support assembled parts? Can you move them relative to each other? In other words, can you do fit checks? Also - does it link up with a reasonable CAM package?

[oldtiffie]

Just another tool

There are some here who may just want to "test the water" so to speak and try out a simple package at little or no cost so as to see how it "fits and feels".

Some have quite simple needs really and so may not need or want or be able to use any of the "high end" very sophisticated packages with all the "bells ans whistles" that go with it - not to mention the costs and "learning curves" - some of which are very "steep".

Most simple and cheap or free CAD packages will do a lot of what is wanted in the shop.

This package is free and was posted by "Steve" - many thanks Steve - as he uses it for his CNC - and he KNOWS and USES his CNC. If its good enough for him, its more than likely that it will do most if not all basic tasks that many may require in the shop. It is a simple "3-D"/"modeling" package with a very good tutorial:
http://www.emachineshop.com/

"Sketch Up" (from "Google") is very good too - especially the "free" version.

CAD is all too often seen as an end in itself, whereas it is only another tool in the shop/"armoury" and as such is only a means to the end - the "job" you are doing.

Its far too easy to "dive into the deep end" with CAD and just get over-awed or over-whelmed by it all and just "give it away and go back to basics".

Some here may not have a high order of "math" skills, but with a bit of common sense, CAD can either solve or help you either solve or by-pass that problem.

I have had AutoCAD since its very early days (25+ years ago - version 2.16 - which pre-dates "Windows"). I have 2004 on my machine as well as three other recent cheaper - and for my purposes now - even better CAD packages in many cases and they range from quite cheap, to very cheap to free. All have their uses and limitations and all perform very well. I have not "fired up AutoCAD" "in anger" for 15 years and will almost have to go back to "square one" and "re-learn it" which is not needed as the simpler cheaper packages "do it" for me now with my small shop and only occasional use.

Most of the stuff that I'd use CAD for can be done on a calculator as I like to use and keep my basic math skills. So I sketch by hand and use my calculator.

The simpler free/cheap packages have good tutorials and "help" files - use them and use them in order to as to develop basic skills and build on them is an orderly and systematic way - there are very good reasons for it.

If anyone thinks that CAD is going to entirely eliminate the manual "sketch" or "scratch" pads they are in for quite a surprise - it just won't happen in many smaller/HSM shops.

Many may have noticed that I sketch manually a lot and post to Photo-Bucket. I also use - and have used for years - my fax machine as I can sketch while I am thinking /talking on the phone and it can be on its way almost immediately to someone who wants it quickly or who (n)either has or uses a computer or a CAD package - and there are still a lot of them.

I usually don't get past the "construction line" stage in either 2-D or 3-D in CAD as my problem has been solved at that stage and "finishing-off" is only putting lip-stick on the pig.

So, its "horses for courses".

Give it a try and stick with it. It can be as frustrating as hell at times, but when you over-come the problems and find out what its limitations and capabilities are in the way you want to use it either in or for your shop - you will glad you did.

But do remember, that CAD is just another tool - nothing more and nothing less.

[BigBoy1]

Getting Into CAD

I'm one of the "old farts" that grew up doing engineering work with a slide rule and drawings with paper and pen. (I still have my slide rule on top of my computer as my "back-up" tool.) I've been wanting to get into CAD but the price has stopped me cold. I called Solidworks and asked about a CAD package and was told that they could get me going with a $4,000 software cost and $1,200 a year maintance fee.

For that kind of money, I can sure buy a lots of pencils and paper!!!

I looked on the internet and found places where you can get CAD packages for $50 but you download the software on-line. Sounds like a den of computer viruses.

The problem I have is I don't want to buy a package and find it doesn't do what I want or is very hard to use. I tried a test package CD from Alibre Software and I couldn't even get their test CD to run. In calling there technical support line and I was just blown off because I didn't have there purchased package.

Are they any reasonably priced CAD packages out there that are user friendly and where a test version can be had to try to see if they are what one wants? All I'm looking for is a package the will generate nice looking 2D drawings. This is for my own personal use, not for a company.

Bill

[RTPBurnsville]

SolidEdge has a free 2D package that is very nice. This is a professional quality software package, check it out.

http://www.plm.automation.siemens.co...2d/index.shtml

No connection, just a very happy user.....

[Michael Hall]

For the money these are hard to beat and for the "once in a while user" the learning curve is not very steep.

http://punchcad.com/products/viacad2d.htm $49

http://punchcad.com/products/viacad2d3dV6.htm $99

There are demo downloads available at punchcad.com

BTW, just a satisfied user, no connection with punchcad.


Michael

[Spin Doctor]

CAD is a tool. Nothing more, nothing less. As I stated before I like AutoCAD, but then it is what I am used to. If I got my start in SolidWorks I would most likely be saying what a kludge. But I think one thing all CAD systems need is a big enough monitor so that you can set the display setting high enough with out needing a micro scope to see what you are doing. This was done in AUtoCAD for a model ship competion I entered before my first wife got sick

http://smg.photobucket.com/albums/v1...rsenal%20Ship/

[Nick Carter]

I'm interested in Rhino, but don't want to bother with the download trial if it does not meet some basic reqirements. These are difficult to discern from their website. Does Rhino support assembled parts? Can you move them relative to each other? In other words, can you do fit checks? Also - does it link up with a reasonable CAM package?

You can group or create "blocks" that are assembled parts. Not sure if there's a way to check for fit other than by eye, although there are a ton of plug-ins that will do all sorts of FEA, etc stuff.
Rhino will output in a slew of file formats so you can use just about any CAM package, as well most will accept Rhino's 3DM file, as it's an open source format. Many people use Visualmill with Rhino.