CAD in creative design, problem solving
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From: Tim Wescott on 17 May 2010 13:37 Existential Angst wrote: > "Jim Wilkins" <kb1dal(a)gmail.com> wrote in message > news:aab5b24b-db71-4514-ac2a-8e4332af606d(a)q23g2000vba.googlegroups.com... > On May 17, 12:41 pm, Tim Wescott <t...(a)seemywebsite.now> wrote: >> Existential Angst wrote: >>> ... >>> Ito of the actual function/design of mechanical parts, has anyone >>> actually >>> solved a "design problem" using CAD? > > http://en.wikipedia.org/wiki/Finite_element_method > > Funny, how calculus (the integral) is in fact the result of FEM, in the > limit as x --> 0, but done analytically (power rules and all that). FEM is > kinda like calculus in reverse, when analytic solutions are not possible. > > > http://www.youtube.com/watch?v=Bt6Q_pVxwl0 > > Nice. But I would distinguish CAD from this type of analysis/animation > program. I guess that depends on what word you assign to the 'D'. If you think that 'CAD' means "computer aided drafting", then yes, it's different. But if you think that 'CAD' means "computer aided _design_" then this sort of analysis program is nothing other than a fulfillment of at least a small part of the promise. I will grant that -- strictly speaking -- it's still not design: analysis is an aid to telling you whether your design process is on the right track, and in the right hands it will even put up road signs telling you where to turn next. But I've yet to see a program that can come close to successfully carrying out the order "check these ten possibilities and tell me which one I want*", much less "I want to increase the speed of my wire brush assembly machine without losing product quality". But I would make the -- entirely semantic -- claim that 'CAD' means "computer aided design", and that in a limited sense we have just that. * With scripting you can check ten possibilities, but you still have to look at the results and figure out what they mean. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
From: Jim Wilkins on 17 May 2010 17:52 On May 17, 1:26 pm, "Existential Angst" <UNfit...(a)UNoptonline.net> wrote: > "Jim Wilkins" <kb1...(a)gmail.com> wrote in message > On May 17, 12:41 pm, Tim Wescott <t...(a)seemywebsite.now> wrote: > > Existential Angst wrote: > > > ... > > > Ito of the actual function/design of mechanical parts, has anyone > > > actually > > > solved a "design problem" using CAD? > > http://en.wikipedia.org/wiki/Finite_element_method > > Funny, how calculus (the integral) is in fact the result of FEM, in the > limit as x --> 0, but done analytically (power rules and all that). FEM is > kinda like calculus in reverse, when analytic solutions are not possible. > > http://www.youtube.com/watch?v=Bt6Q_pVxwl0 > > Nice. But I would distinguish CAD from this type of analysis/animation > program. > -- > EA > > jsw Take that sample truss and adjust the element dimensions until all areas are the same color under load. I've been using electronic design CAD programs for ~25 years. Simulation, analysis and rules checking are essential components of them. jsw
From: Kirk Gordon on 17 May 2010 21:28 Existential Angst wrote: > Awl -- > > In a pointless response to the Village Idiot (Jon Banquer, unemployed > ex-thief of Qualcomm, in his absurd notion of him asking difficult Qs), I > brought up the notions of CAD being more for communication than the design > process itself. > Bonkers of course confuses "difficult" with "rancorous". > > Some refinements of the design vs. communication notion. > > In "art" type design, like, say, for a new car body, certainly CAD could be > useful, as a simple curvature of a line can alter the visual effect in auto > design.. > But this is more of an "illustrating" context than say a parts/machining > context. > > Ito of the actual function/design of mechanical parts, has anyone actually > solved a "design problem" using CAD? > And by design problem, I don't mean radius blends, geometry problems, etc, > for which CAD can really shine, but rather the solution to a "how do I do > this" engineering-type problem. > > For me, the problem is always solved on paper, the essence of the design > clearly present on a napkin. > CAD, for me, is just for telling other people where the holes go, or for > keeping track of the history/evolution of a design.... > > Now admittedly, for things like carburetors, these holes can get perty > complicated, and mebbe CAD would be useful in doping a few things out in > something like that, but I would think mostly it's a tool for > communicating/building, not really thinking per se. > > After all, some perty complicated carburetors were built before CAD, and I > don't know that CAD really improved them. > > But mebbe they did. > > Opinions? Experiences? > Think really big napkins. Endless, boundless napkins, if you like. Think about being able to draw a perfectly straight line, or a perfectly round circle, with just a flick of your wrist. Think about being able to undo a doodle that looks wrong; but without having to scribble over it and mess up the whole deal, or without losing time and train-of-thought when the napkin's full of ink and you need to start over. Think about being able to pick up one of your doodles, right off of the napkin, to turn if over and see if it still looks right. Think about having all your napkins saved in one drawer, so you can easily find an old one and compare it to something new you just thought of. Imagine that, almost by magic, all your doodles and scribbles are done at the same scale, or can be made to scale the same, so that any collection of doodles can be put onto the same napkin for comparison, brainstorming, or thought experiments about the project or problem. Think about this, too: The first step to solving any problem is to state the problem accurately and effectively. I find that having the immediacy of napkin sketching combined with the precision of a CAD drawing can make the problem itself more visible, which often makes it more soluble. What's important is not to let the drawing become a source of delay and distraction that messes up your thought process. The reason most CAD users, including me when I was new at it, have trouble "thinking" with a CAD system is that the mechanics of using the system get in the way of dreaming and imagining and squeezing thoughts out of your brain. When a thought appears in your mind, you want to CAPTURE IT, not go looking for the right command icon, then trying to make up numbers or mouse-clicked positions that you don't even have yet, and then extending and trimming and coloring and layering and more, just to sketch something rough and simple. By the time you've done all that, the fleeting thought that you were grasping for is gone. The solution is not to limit your CAD system to "after-the-fact" refinement or presentation of a napkin-sketched idea; but to become as fluent and comfortable with it as you are with your pencil. Then you'll be BETTER able to play with ideas, and the mechanics of CAD system will be less limiting than the inaccuracy and messiness and size constraints and coffee stains on your napkin. When lines and circles and points of intersection and tangency flow from your mouse the way doodles now flow from your pencil, you'll think better, more easily, and more effectively. To accomplish that level of comfort, you'll need two things. One, a CAD system that's easy and comfortable to use, and to get thoroughly used to. And two, lots of practice. Not necessarily structured practice; but the same kind of constant endless doodling that you now do on paper. One of the reasons I still use AutoCAD Light '97 for much of my design work (despite JB's endless rants about how idiotic I am) is that I like it's UI, and I've spent so many zillions of hours with it that I can can capture ideas using only my fingers, and without distracting my brain. The CAD system is as natural for me as a pencil, but much more effective. I don't need to think about drawing; but only about what to draw. And when I get even the roughest sketch onto my screen, it's a better sketch, more useful, and more easily played with, than anything I could do on a napkin, notepad, or drafting board. It's also more immediate and spontaneous than what I do with more capable CAD software, which still demands my attention for its own needs. 3D shapes? Fitting things together? Test assemblies that actually look like they might work? Later. First I gotta get this thing working in my head. My old and outdated AutoCAD does that for me like no "stronger" system ever has. I once attended a dinner party for a club that my wife belonged to. She knew all the other club members, but I knew nobody; and even my wife didn't know any of the spouses. While sitting around a table of 10 or 12 people, enjoying coffee after dinner, talk turned to something or other that some folks had questions about, and others offered to explain. Instantly, three people at the table, including me, reached into our coat pockets, pulled out our pens, and moved our coffee cups off of the paper napkins they'd been served on. My wife laughed out loud. "You can always tell the engineers in any crowd," she said. "They can't talk or think without a pen or pencil." And she was dead right - about the people at the table, and about the general observation. Thinking - especially the kind involved in design work of any kind - necessarily involves capturing what we "see" in our minds. We need to grasp things that would otherwise slip away, store them outside our heads so our minds are free to keep running forward, and then look at our ideas as a way to understand them, manipulate them, and begin hunting for possibilities our original thoughts had only promised; but not made clear. Getting ideas onto paper (or screen) really is a critical part of the process. Napkins have their virtues, therefore. But so did slide-rules, and for many of the very same reasons. When was the last time you used a slipstick, even for rough calculations or estimates? Pick a CAD system you can learn to use without effort, that you can play and doodle with. Save the high-powered software for later. You'll be amazed at how many napkins will be spared, and how much more robust your thought processes can become. KG
From: Cliff on 18 May 2010 05:50 On Mon, 17 May 2010 10:37:02 -0700, Tim Wescott <tim(a)seemywebsite.now> wrote: >Existential Angst wrote: >> "Jim Wilkins" <kb1dal(a)gmail.com> wrote in message >> news:aab5b24b-db71-4514-ac2a-8e4332af606d(a)q23g2000vba.googlegroups.com... >> On May 17, 12:41 pm, Tim Wescott <t...(a)seemywebsite.now> wrote: >>> Existential Angst wrote: >>>> ... >>>> Ito of the actual function/design of mechanical parts, has anyone >>>> actually >>>> solved a "design problem" using CAD? >> >> http://en.wikipedia.org/wiki/Finite_element_method >> >> Funny, how calculus (the integral) is in fact the result of FEM, in the >> limit as x --> 0, but done analytically (power rules and all that). FEM is >> kinda like calculus in reverse, when analytic solutions are not possible. >> >> >> http://www.youtube.com/watch?v=Bt6Q_pVxwl0 >> >> Nice. But I would distinguish CAD from this type of analysis/animation >> program. > >I guess that depends on what word you assign to the 'D'. If you think >that 'CAD' means "computer aided drafting", then yes, it's different. >But if you think that 'CAD' means "computer aided _design_" then this >sort of analysis program is nothing other than a fulfillment of at least >a small part of the promise. > >I will grant that -- strictly speaking -- it's still not design: >analysis is an aid to telling you whether your design process is on the >right track, and in the right hands it will even put up road signs >telling you where to turn next. But I've yet to see a program that can >come close to successfully carrying out the order "check these ten >possibilities and tell me which one I want*", much less "I want to >increase the speed of my wire brush assembly machine without losing >product quality". > >But I would make the -- entirely semantic -- claim that 'CAD' means >"computer aided design", and that in a limited sense we have just that. > >* With scripting you can check ten possibilities, but you still have to >look at the results and figure out what they mean. One might propose that design implies 3D in most cases but that simple drafting/drawing needs only 2D. -- Cliff
From: Cliff on 18 May 2010 06:01
On Mon, 17 May 2010 11:25:17 -0400, "Existential Angst" <UNfitcat(a)UNoptonline.net> wrote: >In "art" type design, like, say, for a new car body, certainly CAD could be >useful, as a simple curvature of a line can alter the visual effect in auto >design.. >But this is more of an "illustrating" context than say a parts/machining >context. Whils it is possible in some cases to have G2 surface relatonships manually it's clearly easier to compute things <g>. Plus you can then use CNC to machine the tools in 3D ... http://www.eng-tips.com/viewthread.cfm?qid=213756&page=3 Think of this in terms of the derivatives along ANY plane cutting the surfaces. WAY over jb's pointed little beak ...... http://images.buycostumes.com/mgen/merchandiser/17477.jpg -- Cliff |