//1bridge.fe (by Rob Kusner, 2 June 1994, at Geometry Center Solder Workshop)
// (minor modifications to script by RK, 25 April 1996, at NIST)

/*test for optimal solder bead parameters for a pair of pads*/

/* this file gives a pair of solder beads connected by a bridge which
will evolve to a nice (symmetric) disconnected pair of beads if the volume
fraction and gravity:surface tension fraction are correct; by varying
these fractions, as well as the other parameters, optimal configurations 
can easily be obtained: note, my gravity has negative (pendant) sign*/

square_curvature 0 /*to allow some smoothing - turn on later!*/

/*pad radius*/
PARAMETER RR=.8

/*wedge angle for the array*/
PARAMETER TT=pi 
/*pi/6: hexagonal; pi/4: square; pi/3: triangle; pi/2: linear; pi: dumbell*/

/*half interpin distance*/
PARAMETER DD=1

/*volume fraction*/
PARAMETER FF=.17

/*gravity:surface tension fraction*/
PARAMETER GG=1


constraint 1 /*the pad*/
formula: z=0

constraint 2 /*the pad rim*/
formula: x^2+y^2=RR^2

constraint 3 /*mirror through wall*/
formula: y=0

//constraint 4 /*mirror through wall corner*/
//formula: x=0

constraint 5 /*the wall*/
formula: x=DD

VIEW_TRANSFORM_GENERATORS 2
//reflect through y-axis
1 0 0 0
0 -1 0 0
0 0 1 0
0 0 0 1
//reflect through wall x=DD
-1 0 0 2*DD
0 1 0 0
0 0 1 0
0 0 0 1

vertices
1 0 0 1 	constraint 3 /*constraint 4*/
2 1 0 1 	constraint 3 constraint 5
3 1 .5 .5 	constraint 5
4 1 0 .5	constraint 3 constraint 5
5 RR 0 0	fixed constraint 1 constraint 2 constraint 3 
6 0 RR 0	fixed constraint 1 constraint 2 /*constraint 4*/
7 -1 0 0	constraint 3 /*4*/ constraint 1 constraint 2
8 0 0 0		fixed	/*display green board*/
9 3*DD 0 0		fixed
10 3*DD DD 0		fixed
11 0 DD 0 		fixed

edges
1 1 2		constraint 3
2 2 3		constraint 5
3 3 4		constraint 5
4 4 5		constraint 3
5 5 6		constraint 1 constraint 2
6 6 7		/*constraint 4*/ constraint 1 constraint 2
7 7 1		constraint 3 /*4*/
8 8 9		fixed	/*display green board*/
9 9 10		fixed
10 10 11	fixed
11 11 8		fixed

faces
1 8 9 10 11		density 0 /*display green board*/
2 1 2 3 4 5 6 7


bodies
1 2 volume FF*TT density 1

read

P 9
P 8
transform_expr "2a2b"

col:=set facet color brown where id=1 or id=3 or id=4 or id =5
col

inf:={printf "volume fraction"; print FF; printf "gravity:surface tension fraction"; print GG;printf "number of bridges"; print pi/TT;printf "1/2 interpin distance"; print DD;printf "pad radius"; print RR}
inf
doit:={G -2*GG;r;l .2;r;V;u;V;u;g;t .06;w .003;V;u;V;u;V;{g5; l .2;t .06; w .003; t .06;V;u}2;V;u;U;{g5;l .1; t .04; w .002; t .04;u}10;g10;inf}