He brings his own "luck" by repeating the same goofy mantra that is not
just wrong and easy for a lazy guy that can't spell and suffers poor
grammar, like me, to argue with, but silly, which adds to my entertainment.
I *respond* to anything that gives me entertainment. The quickest way
to stop my fun is to stop saying stupid things. Other than that, you
need to wait until I get bored, which will be somewhere between soon and
never, my choice.
Using FREE News Server: http://Motzarella.org
Hardly! Unless what you are saying is comparable to saying buying a
table saw is a waste of time because it is not a complete wood shop, and
it only cuts straight lines like they used 1000's of years ago.
I have no problem at all with CNC tooling. But, I could care less if SU
interfaces with Robotoys $30,000 CNC router.
No more silly than disparaging a piece of free software because it
doesn't interface with a $30,000 CNC router.
Talk about silly?
And yet only a short time ago woodworkers had no access to a free 3D
drawing program as capable as SU that they could use to draw up projects
that have been made by wood workers for hundreds and even thousands of
No need for me to look up your specific project. Not one person has
ever said SU is the perfect tool for every one, or every project. I've
built enough stuff, and looked at enough stuff others have made, to know
SU is more than adequate if not over kill for most of the stuff I make,
and most of the stuff I see others make. Swingman found it good enough
to design kitchens he's built, and $200,000 home he is building. The
internet is plastered with all sorts of stuff SU was used for designing,
much of it pretty dammed complex.
OK, you made me look at that, and see I've looked at it myself before.
Doesn't look like something that would give SU much of a problem, and
I'm not sure why a CNC machine, or much more than standard tools most
wood workers have on their shop would need to build it. The Vikings
built boats fancier than that with out computer software. Are you saying
one can't draw that up with SU or even w/o CAD program at all? I'm no
SU expert, but sure looks like straight and curved lines, same as have
been used to build wood stuff for 1000's of years, with and w/o SU,
computers or heaven forbid, even electricity?
I'm pretty sure SU uses a lot of techniques not available 2300 years ago
and a ton not even available free to wood workers ever before in the
history of mankind. Your point is unclear to say the least.
Yes, exactly. Also that SU meets and exceeds the needs of most hobbyist
and small shop woodworkers most of the time. Goody for all of us.
And I still don't see how a wood worker that normally would not use any
CAD program would be "dumbing down" by learning to use a free design
tool. About the only problem I see is they might end up having more fun
designing stuff than actually building it. This actually happened to
me. I got into computing so I could use it to draw up stuff I was
building. This was in the early 1980's and I got a copy of design cad,
and I spent about 100 times longer figuring out how to use the program
than I would have just using a pencil and paper for a shed I was
building. I ended up becoming obsessed with computers and programing.
Prior to that, I was obsessed with wood working. I found computing met
most of my "creative" needs, I could "build" programs that did all sorts
of things, mistakes along the way cost nothing, no lost material, no
lost fingers and so on. Wood working slipped into the background, and is
still there for the most part...
For those that use SU as a "stepping stone" to expensive CAD programs, I
hope they don't get pissed off if they find SU met most of their needs
as it was. For those that learn SU and find it is not suitable for all
their needs, I hope they are not so dumb as to think SU is the end all,
be all in CAD programing, particularly when EVERYONE has said it is not,
and not meant to be a fancy expensive CAD program that interfaces with
$100,000 CNC machines, yet, it still is the perfect design tool for most
wood workers with a hankering for computer design.
Using FREE News Server: http://Motzarella.org
I do that all the time. I doodle a lot. Very relaxing. It is my
version of a 'game'
I get to make silly doodles too like: (Notice that it is a true
When I looked at SU, I asked several questions.
Will it do this? Will it do that? When the answers came up negative, I
decided not to waste my time.
Somehow, you decided that my decision of not wasting my time
disqualified me from making a judgement whether or not SU filled my
It didn't do what I wanted it to do. No need to look further. "This is
a pretty good band, but all they do is play Cat Stevens songs."
I discovered SU's limitations by investigating its capabilities. It
seems that Google also figured out that it came up short for many
others. They padded the project with LayOut, for a price. That covered
some of my needs, but still there was no reason to drop any amount of
money on capabilities I already owned and learned.
Why are you having such a problem with that, Jack? Or are you just an
What made me decide you were posting drivel with regards to SU was you
saying SU doesn't to X and Swingman would explain that it would do x or
post links that showed it would do X.
Again, I have no problem with SU not doing what you want. Some people
think using SU will degrade expectations and abilities of many. I think
your constant complaining about it's perceived limitations might
discourage some from learning it.
Even though I only heard them once on the radio...
Perhaps, but most of it's limitations you noted where shot down by those
that actually wasted time learning what all it can do.
No one ever said anything about you dropping what works for you.
Everyone has said SU is not, nor claiming to be, a full blown CAD
program. If I needed a full blown CAD program I guess I would spend a
ton and a half of money on AUTOCAD... Few common woodworkers need
AUTOCAD, or anything near autocad.
Well I am an asshole but that's not the problem I have with you trotting
around bashing SU. I'm one, like so many others that tried SU, thought
it a toy, tried it again, thought it was screwed up. Tried it again, and
found it was much much better than I first thought, and decided to put
in some time to really learn what it could do for me. Happily, I found
it did about everything most hobbyists and small shop owners would need,
and then some.
What made me keep pushing on with SU was not some dick that never
"wasted" his time learning what it could do, instead, it was some guy
who actually did "waste his time learning it", who's opinion I had come
to respect (Swing) touting it's abilities.
Now, if you think that's a problem I have, tough cookies. I admit I
enjoy the banter back and forth, and considering it's a subject that
also interests me a good bit, I see no "problem" with my participation
in the thread even though it is getting a bit long in tooth,
particularly since it's likely to erupt again, next time you say
something silly about SU.
So, let me ask you: Why are you having such a problem with that, or are
*you* just an asshole?
Using FREE News Server: http://Motzarella.org
Give it a try. It's a simple parabola with a curve length of 48.000" and
with the focus exactly centered between the two edges. It's an optical
device, and it seems to work acceptably with points calculated every
0.010" and cut with an accuracy of +/- 0.001".
It's symmetrical, so you'll only need to plot one side (2401 of the 4801
The trough I was working on when this thread started positions the 4x8
mirror crosswise to produce a temperature above 1400F, and it'll need
9601 points for the full width.
FWIW, even the primitive MS-DOS (pre-Windows) drawing/design software I
first used was capable of handling the job.
A bandsaw can make the cut. The question is: can you cut the entire set
of ribs with a bandsaw within the +/- 0.001" tolerance? You'll want to
use a /very/ sharp pencil.
You're right, we've done a lot without computers and software - but I'd
bet long odds that we've been able to produce more new design solutions
since the introduction of computers than in all the time before them.
It's a good tool technology - so why not use it as well as it can be used?
I hear you wanting to make a distinction between commercial activity and
hobby activity, so let me respond to that by saying that my immediate
interest doesn't fall neatly into either category. It's simply a
woodworker's attempt to produce a real solution to a real problem, with
the knowledge that a good solution can make a /lot/ of lives better.
Then let me clarify: 2300 years ago Euclid worked only with straight
lines and circular arcs; today SketchUp works only with straight lines
and circular arcs. The only difference is that the SketchUp user doesn't
need (and almost certainly doesn't have) anything approaching Euclid's
understanding of geometry.
A lot has happened since Euclid's time. His work in geometry led others
to use symbols to represent frequently-used values, and that developed
into algebra - which when applied back to Euclid's work resulted in
trigonometry and what we now call analytical geometry - which eventually
motivated calculus so that we could apply all of the above to non
I think our disagreement grows out of the types of woodworking we do.
I'm understanding that you see it as a fun toy and are interested in
appearances, while I'm looking as it as a design tool for producing
constructs that /do/ things - and I care a lot less about appearance
than I do about function.
"Free" is nice, but not as important to me as being able to do a good
job - and although you seem
determined to make "free" a justification for ignoring two thousand
years of advances in geometry and mathematics, I actually do use that stuff.
Turns out there are plugins for Bezier splines, I'm an idiot for not
looking for that sooner. I am not sure how easy/possible it is to get
a parabola from a Bezier, but if not it's certainly possible to add
the ability to do a parabola to sketchup through ruby scripting. I'm
not even sure what all the names of the curves the plugin can do mean,
but I am guessing it can be done with the plugin.
Bezier Spline v1.2
At first I thought you couldn't move the control points again once you
commit with a double click because they don't come back up when you
click on it, but you can edit through the right click menu.
So there you go, Sketchup can do complex curves.
Of course it can, and it could be approximated closely with enough
bezier splines. It'd still be necessary to calculate the positions of
the end (and probably center) points, so I'd guess that it'd be more
practical to just connect all 4801 of those points with straight line
I could also take time out to learn to write Ruby, but the version 1
design got finished while all this discussion was going on, and I just
got a call from the manufacturer of the fin-tube component letting me
know that it's on its way - so I'll probably do the usual and just make
photos of the prototype. I figure there's not much time or effort saved
if I have to go off and learn yet another programming/scripting language.
The fin-tube stuff is kinda pretty in a geekish way. I'll post a photo
of a sample in case anyone's interested in weird hardware. See
I scaled it so it sorta-kinda looked like 48"... LOL.. I guess that
won't do for Morris, eh?
But, hey, it's a starting point, no? (The other problem with the
trace, is that it goes up and down both sides of the line.
Hold my beer, I'm going to try something....
I'm certain somewhere between college algebra and analytic geometry, I could
have calc'ed the required curve. All kidding aside for someone just itching
to get dirty with Ruby, here's the chance to contribute to the Sketchup
library of add-ons. Spin a cone and intersect it with a face describing the
curve, or just calculate the points and connect them. More generally, maybe
just import a list of ordinates from a spreadsheet and plot them. This would
be generally useful for lofting a canoe hull, for example. Is that getting
too far out of the realm of woodworking?
If woodworking is "making something out of wood", then the realm can
become awesomely wide as soon as "design" becomes part of the picture.
As far as the length of curve problem is concerned, there are at least
three ways to approach the problem:
 Set up a relation L = f(a), where L is the curve length, a is the
focal length, and f(a) is a definite integral representing the length of
the curve between limits - and work "backward" to produce the relation a
= g(L). Once a is known, all the rest is "duck soup".
 You can also set it up as a limit problem, but that's really just a
way to sneak up on the integration method without getting your hands
dirty with calculus.
 You can also "cook" the geometry (locate the vertex at the origin,
choose a convenient value for the focal length, etc) and compute the sum
of the lengths of segments of some tiny constant value (say, a millionth
of a unit). Then use the ratio of that (cooked) length to the desired
length to arrive at the focal length of the parabola you want to
produce. This method requires a certain measure of care in avoiding
cumulative computational error, but would probably be easiest for folks
who aren't comfortable with integral calculus or limit theory.
I suppose I can claim to be programming 'literate' (I've used a over a
dozen programming languages in my work and designed one one programming
language for which I implemented/published/sold a compiler). I browsed
the Ruby programming pages and decided that the benefits just wouldn't
provide an adequate return on my time/energy investment; and I attached
a higher priority to completion of the solar engine project than to
adding yet another "wart" to SketchUp.
Would your canoe hull be stronger if you used a catenary rather than a
parabola? Is there a marine architect in the house? :)
The two thoughts were unrelated. Thinking of a generalized import solution,
with the hull profiles as a further example beyond just the parabola.
Which language? AutoLisp put the bread on my table the entire latter half of
the 80's. Since then, I've more or less stuck with C++. Dr. Geisel would be
pleased, I think, with just how nicely that language can read when written
in iambic pentameter. Not in CAD systems, though. They're just part of a
multitude of hobbies. I build financial data systems by day.
PL/C (Programming Language for Compilers) was based on and extended BNF
to include output, external references, and inlining of other code. It
was a tool that could be used to produce interpreters and translators
(from any langage to any other language, including spoken languages);
and was written up in the March '84 issue of DDJ.
I've done a bit with financial systems. If you're interested you're
welcome to peruse a (somewhat sketchy) resume at
It never occurred to me to write code in a poetic form. :)
Of the languages I've used, I've liked C and APL best.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.