The blob in all its glory:
Nice crescent by inverting a ellipsoid on a sphere.
|Click on the snapshot to download the blob's stl file.|
# name of the blob project = "blob30"; function w = f(x2,y2,z2,c,r,e) 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 w=x.^2+y.^2+z.^2 - 1.0; 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 = 0; # 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 = [0,0,0]; r_outer = [35,75,20]; source("../octave/func2stl_v01.m"); # do all the calculationsGNU Octave