Numerical representation: Seung-Nelson lattice
![](slide0005_image023.png)
deform lattice by constraining
some node positions
![](slide0005_image025.png)
minimize elastic energy of k springs and G springs
using conjugate gradient method
Altering resting metric: adjust
unstretched lengths lij
energy = k (1
- á )
![](slide0005_image027.png)
energy = G (|ri - rj| - lij )2
i
j
accurately represents elastic
material for small lattice spacing