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Once you have found in interesting design inspiration for your guitar, you need to reverse engineer the basic shape of the existing design before you can begin to make the changes that give your guitar its unique shape and style.
Once you have found in interesting design inspiration for your guitar, you need to reverse engineer the basic shape of the existing design before you can begin to make the changes that give your guitar its unique shape and style.
When we trace imported data using AutoCAD, we stay away from splines, polylines with control points, NURBS, and such model the outline and important landmarks (e.g., nut, High E saddle, 21st fret, etc.) using points, arcs (trimmed circles), straight lines, and object snaps. #OldSchool
A Google search (malinoski rocket specs) yielded a Reverb.com listing of a former sale that contained the string length (25.5") and the number of frets (24).
A Google search (malinoski rocket specs) yielded a Reverb.com listing of a former sale that contained the string length (25.5") and the number of frets (24).
Using the "imageattach" command , a screen shot of the guitar was brought into AutoCAD and points were placed (nut , 24th fret, high E saddle) to provide sufficient data to (a) orient the guitar's centerline vertically and (b) scale the guitar. The image was then placed into an "image" layer and locked.
Using the "imageattach" command , a screen shot of the guitar was brought into AutoCAD and points were placed (nut , 24th fret, high E saddle) to provide sufficient data to (a) orient the guitar's centerline vertically and (b) scale the guitar. The image was then placed into an "image" layer and locked.
FYI:
FYI:
Point Style
Point Style
AutoCAD defaults to a single pixel point or node. It is all but invisible & essentially useless.
AutoCAD defaults to a single pixel point or node. It is all but invisible & essentially useless.
Use the "ptype" command to bring up the Point Style dialog box and set the display of points to something visible & useful.
Use the "ptype" command to bring up the Point Style dialog box and set the display of points to something visible & useful.
To ensure that the image to be traced has an orthogonal centerline,
To ensure that the image to be traced has an orthogonal centerline,
- Purposely rotate any drawing off the (near) vertical or horizontal,
- Establish the guitar's centerline using carefully placed points and lines,
- Establish an orthogonal line off the centerline
- Use the Rotate command's "Reference" feature to snap the centerline onto the orthogonal reference line
Scaling Guitars from "Body Shots"
Scaling Guitars from "Body Shots"
Stewart McDonald's online Fret Position Calculator is a very handy tool for reverse engineering guitars from photographs of guitar bodies (i.e., incomplete necks). All you need is to be able to model a few frets... the further away from each other, the better.
Stewart McDonald's online Fret Position Calculator is a very handy tool for reverse engineering guitars from photographs of guitar bodies (i.e., incomplete necks). All you need is to be able to model a few frets... the further away from each other, the better.
- Let's say your photograph is cut off just above the 12th fret (i.e., the one typically with two fret dots). Model the 12th fret (a line down the middle of the fret ) and then the last fret (in this case, the 24th fret the same way... smack down the middle of the fret).
- Plugging in the appropriate data—number of frets and string length in inches for an electric guitar—yields a matrix of fret positions, lengths from nut, and fret-to-fret distances. In this example, (12th and 24th frets) the positions from the nut are (12th) 12.750" and (24th) 19.125".
- The mathematical difference is: 19.125 - 12.75 = 6.375"
- Using the Dimensioning tool, measure the length between the two frets of the imported AutoCAD drawing. Let's say the dimension (to 6 places) is 1.662917"
- Calculate the appropriate scaling ratio. Since 1.67 is smaller than 6.4 , well need to enlarge the photo: 6.375 / 1.662917 = 3.83362489
- Use the SCALE command to expand (or shrink) the photograph and fret different dimension by the correct ratio.
- Once you confirm the correct length between frets, the photograph is now nominally at full (1:1) scale within the drawing. Trace away.
Once the imported image has been appropriately oriented and scaled, place points around the periphery of the guitar body.
Once the imported image has been appropriately oriented and scaled, place points around the periphery of the guitar body.
Use a series of 3-Point circles in conjunction with the Object Snap "Snap to Node" & Snap Tangent" to recreate the image shape. Trim the circles to create a complete set of Ogee-ed (tangent) arcs defining a first-pass traced body.
Use a series of 3-Point circles in conjunction with the Object Snap "Snap to Node" & Snap Tangent" to recreate the image shape. Trim the circles to create a complete set of Ogee-ed (tangent) arcs defining a first-pass traced body.
CNC controllers think in terms of straight lines (G01) and arcs (G02 & G03).
CNC controllers think in terms of straight lines (G01) and arcs (G02 & G03).
My advice*?
Stay away from splines, NURBS, and polylines with control points. Creating Ogee-ed arcs takes a wee bit more time but the effort is worth it in increased productivity from continuous, offset tool paths. #NoHardStops
Nominal shape of the traced "Rocket" (left) & the various arc segments comprising the joined polyline (right)
The traced "rocket" body can now be exported into a new AutoCAD drawing for further development.
The traced "rocket" body can now be exported into a new AutoCAD drawing for further development.
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