1. 3D Heart model

A heart described as implicit function by the equation

\[ (x^2 + \frac{9}{4}y^2 + z^2-1)^3 - x^2 z^3 - \frac{9}{200} y^2 z^3 = 0 \]

reference: https://tpenguinltg.wordpress.com/2014/02/15/representing-the-heart-shape-precisely

!ngscxx -c implicit_surface.cpp; ngsld implicit_surface.o -lngcore
!source ~/.zprofile ; a.out

from netgen.stl import STLGeometry
from netgen.webgui import Draw

geo = STLGeometry("heart.stl")
mesh = geo.GenerateMesh(maxh=0.1)
mesh.Curve(3)
mesh.FaceDescriptor(1).color = (0.73,0,0)
Draw (mesh, euler_angles=(-75,-3,2), radius=1.2);