Guitar Design User Guide
Overview
Guitar Design is a Java application to aide in the design of guitar
body shapes. Body designs are specified with control points which indicate
the general shape of the design; as the points are dragged to new positions,
the body shape changes in the same direction. By moving (and adding and deleting)
control points, a body design can be refined until it has the desired shape.
The design can be printed full size for use in making templates for guitar
construction.
Starting
To start Guitar Design, either double-click on the GuitarDesign.jar file
(Windows or Mac OSX), or type
java -jar GuitarDesign.jar
in a command-line window. When the Guitar Design application is opened,
a blank design screen is displayed. To begin a new design, select "New Design"
from the "File" menu. The application will then be waiting for you to place
the control points for the design; the points will be displayed sequentially
wherever you click the mouse. When finished, select "Sketch curve" from the
"Edit" menu. The curve corresponding to the control points will be drawn,
along with the control polygon consisting of line segments connecting the
control points and the matching half of the design if symmetry is selected
in the Graphics dialog (discussed below). The design can now be refined by
dragging the control points; as a point is dragged, the region of the curve
in the vicinity of the point will change to follow the movement of the control
point.
Notice that when a control point is clicked on with the mouse, it becomes
highlighted; this is important when adding, deleting and altering the wieght
of points (see below), as the operation will apply relative to the currently
selected point.
Some general design principles
- It takes relatively few control points to create a pleasing design.
I generally use only 9 for symmetric acoustic designs.
- The curve will always pass through the first and last control points.
- At the endpoints, the curve will be tangent to the control polygon;
thus, to get a symmetric design to meet at the ends without a cusp, the
end two control points should be on a vertical line, as in the design above.
File Menu
The file menu contains items for opening, saving and printing designs.
New design
Select this to start a new design. After this item is chosen, the application
will be waiting for you to click at the position of each successive control
point, which will be drawn as a circle on the design. When finished placing
control points, select "Sketch curve" from the "Edit" menu; the control-point
addition process will be ended, and the curve and control polygon drawn
on the design.
Open design
Self-explanatory
Save design, Save design as
Self-explanatory; however, it's worth noting that the design parameters
are saved as an XML file. This file is plain text, and can be inspected
with a text editor if desired.
Print design
Select this item to print a design out. This brings up a dialog asking
whther the design should be printed either on a single page, full size,
or just the left or right half (useful for symmetric designs). This is
followed by a dialog asking for the page orientation (landscape or portrait).
For the full size and left/right half printouts, multiple pages will be produced
which overlap slightly so that they can be pieced into a single sheet for
use in constructing a template.
Edit Menu
The "Edit" menu contains items for displaying and altering the design.
Sketch design
The "Sketch design" item simply causes the design to be drawn onscreen;
this is usually only used to stop the addition of control points and cause
the design to be drawn when "New design" has been selected from the "File"
menu.
Add point
This item is used to add a control point. This is useful for refining
a design; adding a control point gives additional flexibility in specifying
the shape of the design curve (though too many can make it difficult to
create a smooth curve, resulting in unappealing lumps). It's necessary to
select the control point that the newly added point will follow before choosing
the "Add point" menu item:
- Select the control point that the new point is to follow by clicking
on one of the existing control points
- Choose the "Add point" menu item
- Click at the position for the new control point; the new point
will be drawn at this position, and the curve will be altered accordingly
The newly added point can be dragged to refine the curve shape.
Delete point
This item is used to remove a control point. It's necessary to select
the control point to be deleted before choosing the "Delete point" menu
item:
- Select the control point to be deleted by clicking on one of
the existing control points
- Choose the "Delete point" menu item; the selected point will
be deleted, and the curve will be altered accordingly
Alter weight
This item is used to affect the amount of influence a control point
has on the curve. The default weight of a control point is 1: if its weight
is increased to 2, the curve will be drawn more closely to the point; if
the weight is increased to 3, the curve will pass through the point, and
may even forma a cusp (sharp corner) at the point. Increasing the weight of
a point can be useful when defining a cutaway for access to the higher frets.
It's necessary to select the control point whose weight is to be altered before
choosing the "Alter weight" menu item:
- Select the control point whose weight is to be altered by clicking
on one of the existing control points
- Choose the "Alter weight" menu item; a dialog will appear in
which you can select the point's weight
- When the dialog is closed, the curve will be redrawn to reflect
the control point's new weight
Display Menu
The Display menu contains items that affect the display of the design
Control points
When checked, control points will be displayed. This will usually be
desired, except possibly when a completed design is being printed.
Control polygon
When checked, the sequence of control points will be connected with
line segments.
Curve
When checked, the curve will be displayed. This will usually be left
checked.
Show display dialog
This item brings up the display dialog, with the following items:
- Units: allows quantities to be specified in either inches or centimeters
- Grid: selects whether a rectangular grid should be drawn in the
display window
- Grid width: specifies the spacing of the grid, if any
- Symmetry: specifies whether the design should be symmetric about
the centerline; this is often desireable for acoustic guitar designs
- Design window scale factor: specifies the fraction of actual size
used for the onscreen display
- Souldhole: selectes whether a (round) soundhole should be drawn
on the design
- Soundhole diameter: diameter of soundhole, if any
- Soundhole center: the location of the center of the soundhole
from the edge of the design grid
- Outline: selectes whether a rectangular outline is drawn in the
design window; this is useful for keeping a design within a specified length
and width
Show geometric parameters
This item brings up a dialog with geometric parameters for the current
design
- Length: gives the length of the curve; note that if symmetry is
selected, this gives the length of only one half of the curve
- Area: gives the area of the design
Comments/questions: jsevy@cs.drexel.edu
