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Everything posted by francoisdenis

  1. David, following my experience, the way you work is too approximative to convince, for example we do not agree about the measurement of the easiest arc to measure !! for me the black circle is the better one. Why do you persit to prefer the red circle against the evidence? Is it because that match your theory of the "cremonese traditional geometry" ? It is not a correct approach for me. Again, my conviction is that circles has been used rather than ellyps but it is difficult to prove. May be I miss something It seems to me that your geometrical method of research could generate more approximations than the original outline itself! My opinion is that the best way to know what is the value of this technique (bendind) is to try it. I have asked to Marty to give me the process to draw the strad guitar and until now the only response I get is that it is better to use a carbon rod.... For me I understand that the quality of the shape will depend of the quality of the material. How I can manage the quality of the rod with the form- we will see What I know for sure, it is that the setting of the main dimensions done, the drawing of the shape with a compas take me less that 60 seconds (I can easily give the demonstration of that) How many time it will take with the carbon rod? We will see if the supposed efficiency of the method can be accepted as a good argument against the use of the compass. Using the most accurate method to research the centers , their measurements are less that the third of the width in the both sides
  2. Absolutely Yes David, exactly the same way you think to "prove" the use of integers (Except that I will not say "prove" in the two cases )
  3. Wonderful, so we do not have the same readings! What is certain is that I do not allow to have the beginning of an opinion about the bank act of 1694 related to the formation of the bank of England (and unfortunately I have no vids suitable to share with you on this topic) jezzupe receive the light from you.Thank you David
  4. You will understand I think that everything that is done in this world since the beginning of mankind is dependent on access to three types of resources that are: materials, storage of information, and calculus possibilities. To understand something about how the world evolves, you have to consider only these three factors. If none of them change the society remains static (and the forms too), but if only one of the accesses to one of these three resources moves then the human society is unbalanced and will start moving towards the search for a new balanced. Any social, technical, scientific, technological or political evolution depends on the level of access to these three types of resources. The answer to your question is here. Something happened after the Renaissance, Something happened at the turn of the XXI° century , did you notice? Regarding Strad's or Amati's non-existent notebooks it is typically the sort of argument used by those whom this idea suits because it simply reinforces that it is not useful to spend time reading and question themself. Have you once in your life, tried for weeks to understand a single paragraph of an old treaty? What have you read and understood from Hans Schmuttermayer, Mathias Rorictzer or Arnault de Zwolle? Yet here are people who have left notesbook which you imagine that it would give you a ready made solution ... You did not read them and it is certain that if you did it you would understand nothing of it. It is a pure illusion to believe that writing it conveys a truth simply accessible by a reader centuries after it was written. Zwolle is a perfect illustration of this, in another area Vitruvius ceases to be intelligible at the beginning of the 17th century when the long tradition of commentators of the text begins. I published a comprehensive and in-depth analysis of Zwolle's text did you read it, did you understand it? I'm sure not. To convince yourself of this, it is enough for you to imagine the number of terms you use without requiring it to be explained. These implicit meanings nurture understanding and if they are not passed on any recipe becomes difficult to understand The "Librem segreti de buttegha" is an illustration that understanding of a writting can be very confuse
  5. What is the diameter of Saturn for you ? Do you consider that the moon is part of the earth? You chose the first ring and another one will prefer the second one because the match is better with his theory etc... If you introduce this kind of variations as parameters, you can demonstrate whatever you want and force the reality to your hypothesis The answer is: the "hole "- what establishes the relation between the full and the empty , the inside and the outside etc.. the same than in architecture I know that some irrational relations could have been used hurt you because that doesn't fit with what you imagine to have been "the cremonese tradition" But the used of these irrational and the role played by their approximation has been widely demonstrated by scholars. some biblio GROS (Pierre), Nombres irrationnels et nombres parfaits chez Vitruve, in « Mélange de l’École Française de Rome, Antiquité », 88, 1976, p. 669-704 FREY (Louis), « Données architecturales et hypothèse sur la mathématique pré-euclidienne », in Bulletin Antike Beschaving (BABesch), 1989, pp 90-99 TOBIN, R, « The canon of Polykletos », in American Journal of Archaelogy , 79, 1975, p. 307 sq.
  6. I'm afraid that you are may be not joking .... Are you a troll here?
  7. Et merci à vous de me faire partager ce grand moment de culture cinématographique...
  8. The Ancient believed that the regular polyedre with only one diagonal (triangle, square and pentagone) played an important role in the nature with the idea that any canon should be found on this. (see TOBIN, R, « The canon of Polykletos », in American Journal of Archaelogy , 79, 1975, p. 307 sq.) for the triangle the diagonal equal the side and the proportional relation is just 1 to 1 (The VP is one its illustration) for the square and the pentagone the proportional relation is irrational (that means that you can't exactly mesure the side and the diagonal with the same part) but you fine integers close to these relations. -for the square it is the harmonic and sub-harmonic serie 1-1-2-3-4-5-7-10-12 etc..and for the pentagone, the geometric serie 1-1-2-3-5-8-13,... For a while, people were only focus on the second, completly ignoring the first one (a long story) Anyway these harmonic proportionnal relations appear when you rotate a square. `` in all the figures above each terms M-S-L d can be replace by an interger of the serie and produce rationnal ratios PS: If you are really curious to known how the ancient originated their measurements I can provide you a selected bibliography
  9. If you want to find other ratios close to the strad guitar 16 for the width is not a good number 10 would a better one lenght 16,5 (+1,5) width: 10 waist: 6,5 upper bout: 8 rose 3 With these guitar , measurements come from the rotation of the square (as it is often the case) if you want to change all the ratios you have to change your approximation of root of 2 shifting 7/5 to 10/7 But that it is not an easy think to grasp...but anyway we are 100% sure that worked like that The drawing of the rose made on the same principle was a way to symbolise and evoke the "art of the measurement" (square, circle rotation, symmetry, division 12 etc...)
  10. Depends of what you call right or wrong... If we are speaking of the Strad Guitar 1700 Rawlins coll (and I think that we are !) the values 25, 16, 8 , 12 + 2.5 and 4.5 are wrong or less accurate if you prefer (next time, please check we a calculator before asking)
  11. Hum...May be are you also a violin maker ? I can explain another way, something like..." how to do" rather than "why" To make your template give : - 23 parts to the length, -14 parts to the maximum width, -9 parts to the waist and -11 parts to the upper part add 2 parts to the saddle of the table and give 4 parts to the rose that way you will get a good approximation of all the ratio and measurement (even if you the "why" is not important to you, you can at least keep in memory the way how geometry originated the measurements by the means of a process called "commodulation" )
  12. I just called Strad, he's not using his, and he's willing to lend it to me
  13. I forget a detail... The outline The outline appears to be partly draw by a serie of circles. A serie R1=NP : R2=NP/3 and R3= ½ pp’ draw the lower bout The serie R2= ¾ of NQ and R3=qq’ draw the upper bout) The waist could have been draw by a circle equal to ½ pp’ and to straght line (or simply bendding a thin stripe of wood)
  14. How I work My final analysis ot this outline ANALYSE OF A GUITAR OF ANTONIO STRADIVARI Measurements in px horizontal measurements maximum width of the lower part LB pp' 246 maximum width of the rose aa' 70,7 maximum width upper part UB qq' 194,7 minimum width of the middle part MB ee' 157 vertical measurements length body and saddle PQ' 440,1 length of the body PQ 402,1 length tangency OQ 73 length tangency PM 84,2 length tangency PN 234,3 bridge PMbr 80,1 length NQ 167,9 length NQ' 205,9 Surface relations possible ratios for the relation between the width (pp’) and the length PQ and PQ’ (including the table saddle) pp'/PQ 0,612 pp'/PQ' 0,559 The quotient 0,612 matchs the ratio 8/13= 0,615 The quotient 0,559 matchs the ratio 5/9 = 0,555 But a better relation can be found. Actually we notice that : pp'+qq' 440,7 pp'+ee' 403 and we find these ratios even more relevant pp'/pp'+ee' 0,610 pp'/pp'+qq' 0,558 it appears that the both length PQ an PQ’ equal the sum of the widh pp’+ ee’ and pp’+qq’ Other relations in the length The bridge (distance PMbr) is set with a ratio ⅕ of PQ PMbr/PQ 0,199 The waist (N) is set by a ratio 5/7= 0,714 NQ/PN 0,717 The ratio 5/7 sign the use of number (fig left) or the use of a square (fig right) Relations in the width The quotients 0,791 et 0,806 recall the ratio 4/5=0,8 and the quotient 0,287 matches the ratio 2/7= 0,285 qq'/pp' 0,791 éé'/qq' 0,806 aa'/pp' 0,287 the first idea is to retain a simple proportional serie the width (pp’) minus ⅕ = the upper bout (qq’) minus ⅕ = the waist (ee’) In this case the measurements are: pp' qq' ee' real measurements 246 194,7 157 theoritical measurements 246 196,8 157,4 An other possibility worth to be study if we pay attention to the ratio 2/7 which give the measurement of the rose. In this case qq’ and ee’ simply result of the first ratio by a division two and five implying the ratio 1-1 and 2-3 (fig left) pp' qq' ee' real measurements 246 194,7 157 theoritical measurements 246 193,3 158,1 And the end, a division in 14 would allow to set all these measurements with the same unit part. (fig right) This solution solution present the advantage to correspond to what we know of the rules of the “symmetria” as they are smartly illustrated by the Henri Arnault de Zwolle luth drawing of the XV° century. The design give us the opportunity to underline one more time the role played by the serie of numbers of the harmonique section approximation (relation between the square and its diagonal). These ones corresponding to musical ratios of the harmony unisson, octave, fourth and fifth.
  15. I think that it could be a good solution use a bent splines in a way that match with our measurements (metrologique or relative following your preference. I plan to experiment that way this WE I was thinking first to a process the both systems
  16. Marty , I want to test your system this WE to draw the Strad guitar what is the lenght of the strip ? any advise for the wood, section, etc
  17. I think that I had understood that, you third radius is not part of the outline . You need it to place the fourth radius at the good place (the waist) It works as a variable of adjustment and I ask you a question about that: "Is other radius can play the same role?" I will not follow you here , that works if you keep the wrong radius for the lower bout if you take the good one (77,5 px or 5/16 of the width of the lower bout ) You have to define where is the bottom and give a measurement to this radius. How do you manage that if you don't want to define the length? What is the problem? Not copy a Strad guitar xerox do the job the process of the design is the puzzling problem to solve. You have two ratios to set the widths- why do you have this obstinate refusal to add two more ratio to set the lengths ? that will give much more possibilities to draw what ever you want with the advantage to be closer to the original Really, I'm having a hard time to make sens of this
  18. Hi Kevin , so the match with the Strad outline don't change But what is your reference ? Is it LB=246 px or the VP radius ? could you confirm? I explained previously that I alway take the measurements first If you choose to start dividing the width in 3 that means that the radius equal 246/3= 82 px That is a possibility and you are completly founded to think about it. But when the measure the radius the value appears to be 77,5 px not 82 px Obviously, the "77,5" circle has a better match it appears that it is accurately a third of the distance PN (the bottom and the waist) we have PN =234,4 px. PN/3 =78 px So, it appears that basically we have the choice to take measurement form the 1/3 of the lenght ( PN) or the width The both alternative exit- but in this specific case a 1/3 of the length have a better match OK , I understand that this purple circle is not part of the outline . His fonction is to set the the waist at the right place So the idea is to conceive the relations between the 3 tangency points as a consequence of a division of the width We have: WIdth * 4/5= Upper Bout and Upper bout * 4/5 = Middle Bout R1= 1/3 of the Width R2=1/2 of W R3=2/3 of W R4=4/5 of W R5=3/10 of W R3 is (in this case) a variable being adjusted has you want to set R4 (tangency of the waist) in the right place. Just a question: "In this method, is other radius can be used as a variable ? " I agree that, as soon a variable "R" (which is not part of the outline), is introduce to adjust the relation between the 3 tangency points (M,N,O) you can reach a rather acceptable match between these points (Note that the fact that R1 is too big in you proposition is not a problem except if the the radius of the VP is the reference of all the construction (what I suspect : the reason why I insist to ask you "what is your reference measurement) A problem to solve for me is that you the value of the length "appears" (not really known) at the very end of the process. That weird, definetly in contradiction with all the traditions (and still are doing now) It has always been a strongly recommended rule to the craftmen to start from the big and finish with the small It is true with the tools (the coarse before the finest) It is true with the measurements the large to the small (simply to divide the mistake rather than multiply them) At the end (that will be my conclusion): -I understand that it is not a problem for you to apply ratios to the width - I understand that is it a problem to you to apply ratios to the length Can you imagine one second an architect working that way? why erect this useless barrier? PS: about the letter I use to define the different parts, (that help to the understanding) I 'm not the first to do that way H.A.Z did the same in 1450 to draw a luth shape. I like the idea to continue his work I
  19. Hi Kevin, could you explain what is the difference with your previous proposition ? At this scale a proposition remains in a gray area That will help to have a clear opinion if could use letter and compare your measurement with those of the original outline Can you explain what the "exension" is ? (You don't communicate what is your first measure for example)
  20. ...Unfortunately for our ego, we rarely originate ideas. You agree that this system to produce outlines and proportion is not a magic thing but has is own "proportional" logic. If it is logic, it becomes predictable- it was one of the idea of my previous post - drawing outlines is not a big deal but: as soon as you state "this is these system which has been used rather that this other one" that means that you understand how it works. with what the can call the "bending system" what is your project? Do think to some measurements first? If "Yes", how many and how do you control these measurements ? About the question "how works outline"? We can go back to this example of the Strad guitar and study accurately what's going on with the lower part and the bridge All the historical text give the measurement of the bridge in relation with the body lenght so we can check that first the lenght PQ = 402,1 px and the distance of the bridge from the bottom PMbr= 80,1 px and 80,1/402,1= 0,2 so the bridge length is set to 1/5 of the lenght (fig 1) Now we can check what going on with the outline the 3 tangency points M,N,O are important what are there measurement PMtg (lower bout) =85,4 px PN (middle bout) = 234 px PO (upper bout) = 329,1 px so we notice that Pbr (bridge)=80,1px is not the same that PMtg=85,4 px the tangency point is higher What does that mean? let see the arcs radii measurement at the tangency point the measurement of the radius (R2) can be accurate enough we find R2= 77,7 px hum....this measurement doesn't match Pbr or PMtg and, furthermore, it is not a third of the width (pp' (lower bout) = 246 px and pp'/3= 82 px) does that mean that R2 happen by chance? No because we find PN= 234 px and PN/3 =78 px close enough of the 77,7 px Is PN could be R1 the radius of the bottom arc? if we check with the original outline we notice that it is fine And the end, we have this proposition : 1) the bridge nut is set to 1/5 of the length 2) the radii R1= PN and R2 equal PN/3 3) the drawing of the outline start from the bottom (arc R1) and Mtg is correctly placed Doing that we get an accurate measurement for every details even the bridge position and thickness. If somebody can get a better result using another way I will be obviously very interested: but, if you pretend to defend of process you must be able to share more than opinion - but a clear presentation of how accurate and well-argued it is. Kevin fails and I'm still waiting yours, give me all the instructions to make it and I will try (please, not approximate outlines and picture)
  21. Are you defending the idea that Andrea Amati form is the result of a process of try and error ? If yes, I'm curious to see your evidences
  22. Who speak of that ! Not me for sure...
  23. which kind of "calculations" you imagine to have to perform ? Are you speaking of measurements ? ( may be you should make some because 210mm for a mold is widely out of standart ...) if that bother you so much, use a xerox copy and it is always difficult to me to understand what means "absolutely geometric" for you do you think that simple measurements are not geometrique ? PS: Do you have a picture of a violin made following these dimensions and pattern?
  24. "absolutely geometric" ..What does that means for you ?