blob35

  # name of the blob
  project = "blob35";  
   
  function w = f(x2,y2,z2,c,r,e) 

 cen1 = [50,140,0];  rx = 60; ry= 15; rz = 15; theta =1.1;
  cen2 = [50,-140,0];
   x  = (x2-c(1))/r(1);
   y  = (y2-c(2))/r(2);
   z  = (z2-c(3))/r(3);
   # function at origin must be <0, and >0 far enough away.  w=0 defines the surface
    c1 = [5,0,0];
    r1 = [60,160,45];
    w = 1./(((x-c1(1))/r1(1)).^2+((y-c1(2))/r1(2)).^2+((z-c1(3))/r1(3)).^2);  

    w = w+1./((y-cen1(2)).^2*(rx^2 + ry^2+(rx^2-ry^2)*cos(2*theta))/(2*rx^2*ry^2) ...
    + (x-cen1(1)).^2*(rx^2+ry^2+(ry^2-rx^2)*cos(2*theta))/(2*rx^2*ry^2) ...
    + (1/ry^2-(1/rx^2))*(x-cen1(1)).*(y-cen1(2))*sin(2*theta) ...
    + (((z-cen1(3))/rz).^2)).^2;

    w = w+1./((y-cen2(2)).^2*(rx^2 + ry^2+(rx^2-ry^2)*cos(-2*theta))/(2*rx^2*ry^2) ...
    + (x-cen2(1)).^2*(rx^2+ry^2+(ry^2-rx^2)*cos(-2*theta))/(2*rx^2*ry^2) ...
    + (1/ry^2-(1/rx^2))*(x-cen2(1)).*(y-cen2(2))*sin(-2*theta) ...
    + (((z-cen2(3))/rz).^2)).^2;

    w = 1-w;
   endfunction;

  # this is for distorting the grid before applying the function
  # note that the undistorted grid will be used to make the stl file
  # just set it to x3=x; y3=y; z3=z; if no warping is needed.
  function [x3,y3,z3]= prewarp(x,y,z)
    R =200;  # center of sphere is at (R+X0,0,0) with radius R (passing through (X0,0,0) ) 
    X0 = 60; # this means that parts of the blob near [X0,0,0] will stay near that point.
    # calculate the inverted coordinate of each point in the 3D grid (x3,y3,z3)
    x2 = x-R-X0;  y2=y;   z2 = z; # intermediate values
    r2 = R*R./(x2.^2+y2.^2+z2.^2);
    x3 = x2.*r2+R+X0;  y3 = y2.*r2;  z3 = z2.*r2; 
  endfunction;

  c_outer = [5,0,0];
  r_outer = [1,1,1];

   xmin = 40;
   xmax = 180;
   ymin = -200;
   ymax = 200;
   zmin = -50;
   zmax = 50;

  step = 4;  # grid pitch in mm  start with 4mm to see the shape quickly.  Once you have it just right, change to 2mm for printing

  source("../octave/func2stl_v01.m");  # do all the calculations