blob42

  # name of the blob
  project = "blob42";  
   
  function w = f(x,y,z,c,r,e) 

   # function at origin must be <0, and >0 far enough away.  w=0 defines the surface

   w = (  0.8*abs((x-c(1))/r(1)).^5 ... 
    -((x-c(1))/r(1)).^4 + ((y-c(2))/r(2)).^2 ).^2 + 1* ((z-c(3))/r(3)).^2 - 0.09*(1+x/1000);  

   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 =2800;  # 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;

  step = 10;  # grid pitch in mm  start with 4mm to see the shape quickly.  Once you have it just right, change to 2mm for printing

   c_outer = [10,0,0];
   r_outer = [200,200,300];

   xmin = -200;
   xmax = 400;
   ymin = -200;
   ymax = 200;
   zmin = -140;
   zmax = 140;

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