I need to draw an array with variable step.
@Anonymous wrote:
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I am drawing the guitar fretboard.
The image is attached.I need to draw an array with variable step.
There is no special function in array command.How do I achieve the desired result?
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The frequency relationship between adjacent half-tones, and therefore the ratio between fret positions, is based on the 12th root of 2 [an octave is a 2-to-1 frequency ratio, and it's 12 half-tone steps]. See the attached drawing. It's with the string length from Bridge to Neck end being 1 unit, not an actual guitar's string length, so you will need to scale the whole thing to your actual string length. And the width of the neck and string spacing are arbitrary, and not specific to a guitar or anything else -- it's just the fret spacing in relation to the open string length that's relevant. But the principle for fret spacing is applicable to any fretted instrument [mandolin, bass guitar, banjo, ukelele, lute, viola da gamba, etc.].
And no, I'm not aware of any capability built into AutoCAD that can do this for you directly in anything like an Array command. But it might be possible to draw some curve that you could divide regularly in some way and project from the divisions to get the right fret positions.
Kent Cooper, AIA 
@Anonymous wrote:
....as far as I understand I should create function which will distribute frets.
Could you advise me on tutorial?
I even don't know what is the name of the language used for programming in autocad....
I could put together a routine that would go through the steps for you automatically and lay out all the fret lines in one command, using the code in the Text in my drawing, but I already did lay them out [at least for the number of frets on the guitar in your picture], and since the relationship will always be exactly the same in terms of spacing between the ends of the open strings, you can just take the fret lines in my drawing and copy them, scaling them collectively to match the open-string length of whatever you're drawing, no matter what instrument or size it is. Use somewhere on the Bridge line as the base point for Scaling, and since the open-string length in the drawing is 1 drawing unit, you can use the distance to the Neck-end line directly for the scale factor. [Or the other way around -- Neck-end line as base point, distance to Bridge line as scale factor.]
AutoLisp is the main language for making this kind of custom routine in AutoCAD [there are other ways, too], and the code in my drawing is written in it. If you want to look for tutorials and sources for learning how to use it, do a Search in the Customization Forum for things like "Learning AutoLisp" or "Lisp tutorials" or similar wordings -- there are many threads asking for such sources, and many suggestions and links.
Kent Cooper, AIA