Page 262 of 339

PARAMETRIC PROCESSING APPLETS
FIGURE 12-10
AtFAB applet toolbar
assembly is defined by the exact same func-
tion. It has the same joinery, corner radius, and
linear direction of push and pull.
Constants
The only differentiating feature is that each leg
is oriented in a unique direction: north, south,
east, west. The north, south, east, west orienta-
tion of each leg is an example of a constant.
Variables
The distance between each of the three tabs is
an example of a variable. Figure 12-8 shows
how overall table length and width is the sum of
these variable distances. With a range between
10–25cm, X and Y define the distance between
the interlocking tabs at the center. N, S, E, and
W have a range of 25–75 cm, defining the dis-
tance from interlocking center to the outer tab.
The overall tabletop length is the sum of N+Y
+S, and overall width is the sum of W+X+E.
Limits
Limits are an important consideration relative
to variables. The Cat in Bag ii Table can only
grow so big before it will become structurally
unsound or won’t fit on a CNC router bed. At
the other end of the range, tabs that are too
close together might compromise a joinery
connection. Limits on the high and low end are
critical to ensuring that parametric transforma-
tions produce outcomes that are functional.
PARAMETRIC PROCESSING
APPLETS
Parametric software programs like Rhino’s
Grasshopper, Autodesk’s Fusion, and others
are indispensable for parametrically developing
designs. However, these advanced CAD pro-
grams are beyond the scope of this book. To
demonstrate parametric thinking, and how
operations work in conjunction with a design,
we used Processing to build individual para-
metric applets for customizing several AtFAB
pieces. Originally built as a proof of concept,
each app balances freedom of choice and criti-
cal constraints to yield outcomes with struc-
tural integrity, harmonious proportions,
ergonomic function, and material fit.
Explore the parametric operations in the two
projects in this section, in order to understand
the effects of limits, ranges, and interrelation-
ships within a design.
With sliders, you can dimensionally transform
the One to Several Table in length, width, and
260
DESIGN FOR CNC
    "