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# Patterning guitar fret positions

charles_tauber
Member Posts:

**6**✭
I used Pro/ENGINEER and then Creo for about 25 years. In that software it is possible, and fairly easy, to position/space the instances (individual elements) of a linear pattern using a formula. I've not been able to figure out a way to do that in Onshape. Anyone know how to do that?

Specifically, I want to position, say, 20 frets based on a recursive geometric series given by the formula L(n) = x(1-(2**(-n/12)), that is, 2 to the exponent (-n/12). The fret number, n, automatically increases by 1 with each fret and the scale length is x. That is, supplying a value for "x", such as 660 mm, with an automatically increasing index, n, would give me "n" correctly spaced fret positions, where "n" would be the number of instances (elements) in the pattern. Either patterning a sketched line or an extruded feature would work.

Currently, I have accomplished it for a specific scale length of 660 mm by providing a "dumb" dimension between a reference point and each fret, i.e. 20 individual dimensions, one for each fret. I'd like to automate that with the use of parameters, an equation and a pattern. Is that possible in Onshape?

Specifically, I want to position, say, 20 frets based on a recursive geometric series given by the formula L(n) = x(1-(2**(-n/12)), that is, 2 to the exponent (-n/12). The fret number, n, automatically increases by 1 with each fret and the scale length is x. That is, supplying a value for "x", such as 660 mm, with an automatically increasing index, n, would give me "n" correctly spaced fret positions, where "n" would be the number of instances (elements) in the pattern. Either patterning a sketched line or an extruded feature would work.

Currently, I have accomplished it for a specific scale length of 660 mm by providing a "dumb" dimension between a reference point and each fret, i.e. 20 individual dimensions, one for each fret. I'd like to automate that with the use of parameters, an equation and a pattern. Is that possible in Onshape?

0

## Answers

71https://forum.onshape.com/discussion/comment/85708 <-- a few different approaches you can use.