Computer Aided Designs and Computer Numerical Controlled Machines

[Andy Birko]

This should help you get started: http://www.youtube.com/watch?v=OPkv9tRuO-c

Just google "getting started with sketchup" and you'll get a bunch of results. Going through simple projects like that will get you used to using the interface and allow you to dig deeper into what you're doing. The advantage to sketchup is that you can get into 3D really quickly and learn how 3D type stuff works.

Another starting point might be Draftsight - an autocad compatible freebie by the same guys who make SolidWorks. They've also got a bunch of videos and such to help you get started drawing.

http://www.3ds.com/products/draftsight/ ... -software/ <= Free cad software
http://www.3ds.com/fileadmin/PRODUCTS/D ... -GUIDE.pdf
http://www.youtube.com/watch?v=u4YO9K6L ... 28&index=1

Niether of these is going to have the surfacing abilities of Rhino or SolidWorks but, at their core Rhino and Solidworks use a lot of 2D drawing to create 3D shapes (SW more than Rhino I think).

[David King]

Andy,
Thanks for the links to draftsight. I've downloaded it for mac.
Jamie,
SolidWorks is strict. Licenses can not be transferred except at the enterprise level and then there's a 33% transfer fee.

For mac users you can currently sign up for and download a free beta version of rhino5 for mac. They've been working on it all year and posting new revisions every couple of weeks. You're stuck with the windows version documentation and no tech support or guarantee of any kind but at least you can play with it without any restrictions in terms of saves, watermarks etc. Go here and fill out the application http://mac.rhino3d.com

The free EDU versions of Autocad products are attractive if you have edu qualifications but anything you save will have the edu watermark and trying to use it commercially will get you into a boatload of trouble according to a dealer friend of mine. He's the one who suggested I go right to Autodesk Inventor.

[Eric Baack]

i am fortunate that i use solidworks for work on a laptop and can model stuff for personal use too. i modeled both guitars that ive made so far and printed off templates in 1:1 scale. i call it printer cnc

[Andrew Porter]

There's another free CAD package, Smart progeCAD http://www.caddit.net/progecad/smart.php the free version of its big brother progeCAD professional. It's 90+% identical to AutoCAD, commands and interface are pretty much the same. Tutorial resources are included in the download. It generates AutoCAD like .dwg files.

[Art Davila]

Can CADCAM be taught to tap tune instrument soundboards ? Got ideas?

Actually using a high quality mic, and a cnc with a sub routine to listen for a certain resonance and shave off micro meters of at a time yes that would not be out of the realm of possibility.

In fact if it was a learning computer it could learn after several tops to fine tune itself to a degree much finer than any human ear could normally discern.

[Louie Atienza]

I started a thread on CNC a long time ago before life's storms hit me. Now that things are finally back on track, it's nice to see more open discussions on this topic.

While it may take time to set up some jobs, from drawing to cutting, there are many benefits. In fact I've been making more performance engine parts on my CNC than guitar parts, by far, the last year or so. But that's where the money was....

I was also fortunate to buy a used seat of a high-end CAM system, and was able to upgrade for about half of what the new system would cost. My CAM has integrated CAD, and while the learning curve was a bit steep, I stuck by it and am pretty happy I did.

If you're only cutting 2D or 2.5D parts, Cut2D by Vectric is probably ihe easiest CAM to use, ever, and cost only $149. The CAD however is very limited. 3D stuff can get a bit complicated, if you want complete control of your toolpaths.

I haven't tried it, but BRL-CAD is an open source solid modeling software that looks real powerful, and has been around a long time.
http://brlcad.org/

[Andy Birko]

This subject came up in another forum and my mind started to wander...

Here's a screenshot I got from a friend who works at a SolidWorks reseller. What's going on here is that a guitar top has been modeled and then a modal analysis was performed on the top. Now, wood is a very variable material in terms of properties but, doing something like this could at least give some ideas on how a new bracing pattern might perform. Entering the actual stiffness parameters of the wood you're using would probably come very close to predicting the actual frequencies of the modes of the top.

I believe the software can also "solve" to move frequencies where you want them. e.g. let's say you have a guitar you like with certain frequency peaks. You now want to build another one. By entering the material properties of the wood for the new guitar, the simulation software could tell you how thick to make the top and braces to get the modes where you want them.

All this said, this software is quite expensive. The screenshot is from SolidWorks simulation and I believe that software is around $15k to purchase (for SolidWorks+simulation) and, it's a pretty low end simulation package with limited capabilities and accuracies when it comes to modal analysis. Higher end packages that work to higher frequencies can run $30k to $100k+

[Art Davila]

The research done by others will someday trickle down to the common builders.
I have read in The Guild of American Luthiers magazine, some article about sound wave and acoustical properties last year or the year before.
I could not follow all of the article but what I did understand told me that we will be using data models for guitar building some day in the future may be not yet but in 10 years who knows.
Seems to me that the data your talking about is already being gathered and papers are being written.
The young builders will most likely be building better instruments based on this knowledge.
Who knows it may well be that no mater how high tech the approach, there really is no better mouse trap just different ones.