blob39

  # name of the blob
  project = "blob39";  

  function w = f(x2,y2,z2,c,r,e) 

    x  = (x2-c(1))/r(1);  # do some simple scaling
    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

    w = x.^4+y.^4+z.^4-1; # <<<<<<<<<<<  THE BLOB FUNCTION

  endfunction;

  # do the scaling
  c_outer = [15,0,0]; # center of ellipsoid for outer surface
  r_outer = [60,180,39];# x,y,z radii for ellipsoid for outer surface
   
  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

   xmin = floor(-75);
   xmax = floor(175);
   ymin = floor(-120 );
   ymax = floor(120 );
   zmin = floor(-50 );
   zmax = floor(50 );

  # 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;

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