Hi Xavier,
First I have to say I am super impressed with your work.Your GH model looks really great! My CAD skills are comparatively pretty limited, but I do want to comment on your exploration of Pythagorean ratios for fretting. Basically you are correct in that these ratios will give a truer, more accurate string vibration frequency for a given chord-the problem comes when you have to play multiple chords that will require subtle shifts in fret location for the strings involved to adhere to the “perfect” ratio. If you are playing an unfretted instrument you can make the small compensations by ear, but with fixed frets this is not possible. The answer is what is called “equal temperament” for fret placement, which uses a mathematical ratio to average the slight variations required so that each chord will be within an acceptable tolerance. The bridge placement with moveable saddles allows for some compensation for string diameter, action height, etc. but unless you will use moveable frets to adjust for the dominant key (like the tied frets of a lute) you will better off with the fixed mathematical progression of equal temperament. For more you can check out Equal temperament - Wikipedia
Now we just need some eto Framworks for doing these dimensional and geometrical constraints 
Hi,
This is sound advice from Abraham, I can’t believe someone is advocating Pythagorean tuning when it was already pretty much done away with by the 1500s especially for fretted instruments. Unless you want to sound high Gothic 1300s? Even Monteverdi advocated his singers to sing mostly in equal temperament. If you wanted to get more sweetness you could try just intonation but that leaves out many keys especially E major which is a stock key of the guitar will sound horrible. Check you tube for many great videos and examples on musical temperaments. The Chinese are still arguing how to divide the octave some 5000 years latter. And the oldest Chinese temperament is equal 12 tone which they found out when the discovered an ancient tomb that still had all the holy bells for their rituals intact and playable. It wasn’t until a few eons that the pentatonic was adopted from Arabia.
I would build a test guitar first using lesser materials instead of using all your precious materials in one go in hopes of perfection. Experiment with that and make sure all is well then you’ll know where things might go wrong. One thing that you could try is not to fret your instrument and use fishing line/lute frets tied onto to your neck to hear the differences in intonation.
Check out these vids the first one reveals why you don’t want Pythagorean tuning for a fretted instrument.
Pythagorean vs Just Intonation | A Paradox of Playing in Tune - YouTube
This is spot on and very informative for guitarists.
Major 3rd Problem of All Guitars in the World - YouTube
This person is doing incredible research.
The Concise History of Chinese Musical Temperament - Episode 1: Formation of Tones - YouTube
RM
Thanks for the encouraging comments! And thanks very much for the info on temperament. I will stick to the scales measurements then.
Thanks RM, I will add those links to my watch list!
Building test necks (and later, hollowed bodies) is in the plans! Im sure the neck fitting to the body will be a first challenge!
Since I already encoded the length for a scale I will try this first.
Thanks 3D Synergy. Your input and that those of everyone are really helpful and motivating to dig deeper in the rabbit hole!
What I love about this GH project is/was such nice incremental build - 8 months later it’s an organized macaroni kind of!
But i have started to make jump points, big red labels, better notes along the references to the original model (the logic sizing too).
Still I have still to learn how to make my guitar gently weep! And find a way to do this without glue or screws? Possible?
So far…
So here a description of the program workflow above…
Far top left the body and the to the right is the ‘start’ with the body building (Pun intended)
Then comes to the right the pickup(s) and bridge cavitie and cable channels.
Next to the right are nut point, fret board, neck-body interface and the neck.
There’s the neck profile choices also and the head.
The head is, like the body, curve independent (copy paste your shape).
middle-middle are the fret boards, scales, fret board definitions.
Lower right are the neck-head interfaces and head definitions. 4 choices for neck definition styles (still not perfect)!
On top with big red big labels are all the CAM ready objects (for body, fret board, neck) to be baked for RhinoCAM strategies. Careful naming of layers and MOPs/strategies is important here to keep some sanity!
Bottom left are ‘parts’ like pickups, tunners which are inserved into modules that go where mapped on the different body parts (like tuners are mapped to the holes in the headstock - 3 different kinds found so far, 2 modeled so far.)
The workflow works organizationally so far. Not sure the logic of the bridge placement is right. The pickups can be moved anywhere also and you can add 2 or 4 pickups if you want anywhere (humbuckers or normal coils). The neck can be made any size but the scaled are fixed length (improvising left for later)…
Still a lot to model in terms of parts - the bit issue with this is where are the screws going to be pre-drilled at. None of them (different parts) follow any standard distances or screw diameters tolerances (inches, mms etc)!!! Im sure architects, engine builders, mechanics, surfboard builders among us can indentify with this… 
Still 1-2 months away before i can carve this IMOHO… Crossing fingers!
Im more worried about how it will sound.
and because
Well done! 
Can you provide a continuous tutorial?
Thank you for the compliment - I saw you do violins - woah!
Unfortunately I’m not planning a tutorial. Not while it is in such a state of spaghetti code. Not while it is such a criss-cross of parameters.
The workflow is quite straightforward working out from a 2D draft plan of the guitar. I drew the body, the neck, the head, the fret-board, the scale for fret positioning. It’s the flattest guitar design possible so it just couldn’t be simpler.
Also Im not a pro-designer - or a guitar player or a musician - I do know music, i can tune the guitar by ear and I know my CNC stuff. But I cannot recommend my design or guarantee it will sound right despite using tonewood etc. The customer who commissioned this will be my tester…
I started about this guitar design the wrong way (because translating plan vs translating guitar logic) - so the center of the universe (the nut) - i got pretty wrong - i used hte middle top of the guitar instead because the plan measured all from there… Im fixing a lot of small issues top to down level in the model since 2-3 months on my hobby time so it’s painfully slow.
The model is huge so lots of time traveling to find the right component and label it (I added a lot of jumpers to help) - Im really thinking about making modules now like I did for the tuners - but i need to reduce the inputs which are all referenced to the model (which i dont/do want). Making groups/clusters would really helps remove the clutter but the clutter’s groups are really helpful to find what goes where (like point references, specific curves mid points, etc…
Im a really advanced scripter (40+ years of experience - dynamicly generated code type), Im not a coder anymore (done plenty of it though) and this is why I love GH - almost no need to debug.
A saying goes that if it was hard to code, it should be hard to decode - and any draft plan can be like that… Where is the center of the universe in the designer’s mind and for what reason - this I failed to learn early on… That’s the key to the next GH guitar design but before I can get there, I need to have at least proof the guitar model works. Once carved we will hear… Not that neck-body tolerances will come first.
Today I changed the vertical walls extruded neck model into the body into a tapered model. Finally… It’s a fine detail but really worth it. My IKEA telecaster neck base is 1mm smaller at the base than it’s top. My customer might have 1.5 mms off. This ‘part’ is ready when i can measure his ‘custom’ neck… Not my making. His is priority, I’m not sure if i will be able to test a home-made neck vs his first. This is a key feature, reason i went so much into its definition today.
I can’t make a tutorial until i take a luthier lesson at least to be honorable to the viewer. One violinist I know and another also guitar collector friend I talked to had many ideas. And it’s a new way to see how to design things - where to start from is different for each, body shape changes too… We will see where this ends tonally…
So I decided to make guitar bridge i can render…
First of a few? The many parts that make a Guitar bridge…
Not sure i did it right but I like it so far…
Lots of holes to model… The key will be putting them down in the right place relative to a main part relative to a sub part…
This begs for rewriting the whole program from scratch…
One part adds a big block there… on top - I guess i also need to reposition a lot of groups… Cluster more… And this is my new hurdle…
Yes, it’s still missing the string guides…
So here’s the last render…
Before Rhino screwed up again the render geometry. I hate how finicky this happens anytime without reason…
So, 2023 ends, 9 months of this project. Not pro focused - on a inspiration basis made. My end goal is to learn Industrial Design, the GH way. I want to thank McNeel and David Ruthen for their development of this IDE which is GH. It’s not HyperCard (my IDE of predilection/my kind of code architecture). Cast-less inteligent functions are my thing.These kind of IDEs are just a blessing for super fast solutions in scritping…
I have always gone the hard way to develop things from the bottom to the top.How often this was the wrong way, the hard way was the soft way… And this is the kind of counter-intuitive way i found this design process (for a guitar) was started - based on a ‘plan’ made in the 1950’s how every part in an electrical guitar was based/positioned.
To put this into the most obvious perspective, the sound of a guitar is first based between the length of the “Nut” to the “bridge”. This is divided into the scale of the tone of the guitar which defines 2 things: first the position of the bridge - usually 2.5 feet and the point where the string interacts with the bridge (not only but assume - there are more bridge types than you want to know), then divide this in 2 and you have the pickup/body zone and the neck/fret zone. Scales of guitars = positioning number of frets among a number of strings etc. So yes, this results into too many tones at too many string tensions which is something im working on still since i can’t say yet how harmonies work yet - not that I can claim to know how to play a guitar yet - if ever…
2024-2026 may tell… Can it be modeled down the tone? I surf on that idea!
Happy 2024!
Flippabled CAM to layer ready baking now possible!
I can CAM the bottom or the top of body, block, neck, head etc now. Useful for laser carving later…
done without planes!
And this was my way to see it before implementing planes.
flipping without planes…
I dont want to do sin/cos/tan of anything if possible…
The key is that now it’s rendered right into the right layers matched to the cam strategy - i still have to match curves to the CAM strategy… Because any new part iteration baked from GH = new curves to Rhinocam layer hence RhinoCAM issues (no longer the same curves). How to make that automatic would be key…
Um, ‘constraints’ 
For those watching this sub, I wanted to know are you interested in the RhinoCAM and the CNC pictures and tricks of the road taken?
The /model/guitar/telecaster/lespaul/whathaveyou/etc has become really complex… More than I thought it would. Trying to keep all of it into one GH file is getting silly.
I started to move parts into Clusters. Assuming their planes are in the right place (new endeavor). Next i have to bake each part in their right layer and at their 0,0,0 xyz referenced part. Relative to the tool’s and the part’s 0,0,0 (plus flipped orientation)…So this is a hard to automate generative part of the job… Im trying to guide MecSoft but they dont really listen… IMOHO… Would love to drive this… I keep trying!
As this is not my “professional” job - nonetheless a PRO level hobby (i dont want to do this half ass way) - It’s amazing how enjoyable it is, how rich the guitar culture and theory and history is - not to mention the variations like the cigar boxes or the huge bass, violins, *chinkas in the east. Honestly I still cannot play a guitar (I play flute, pianos, percs), And I love to watch Guitar how to’s (like the James Bond Theme) - Also got a few pedals (already had some before i needed a distortion pedal) but damn this is enjoyable! And 13 Synthesizers… For which i will make some serious ears, buttons, knobs one day with GH…
But why aren’t guitar parts sizes standard at all if all the distances are the same?