# Laplacian smoothing

Laplacian smoothing is an algorithm to smooth a polygonal mesh.[1][2] For each vertex in a mesh, a new position is chosen based on local information (such as the position of neighbors) and the vertex is moved there. In the case that a mesh is topologically a rectangular grid (that is, each internal vertex is connected to four neighbors) then this operation produces the Laplacian of the mesh.

More formally, the smoothing operation may be described per-vertex as:

$\bar{x}_{i}= \frac{1}{N} \sum_{j=1}^{N}\bar{x}_j$

Where $N$ is the number of adjacent vertices to node $i$ and $\bar{x}_{i}$ is the new position for node $i$.[3]

• Tutte embedding, an embedding of a planar mesh in which each vertex is already at the average of its neighbors' positions

## References

1. ^ Herrmann, Leonard R. (1976), "Laplacian-isoparametric grid generation scheme", Journal of the Engineering Mechanics Division 102 (5): 749–756.
2. ^ Sorkine, O., Cohen-Or, D., Lipman, Y., Alexa, M., R\"{o}ssl, C., Seidel, H.-P. (2004). "Laplacian Surface Editing". Proceedings of the 2004 Eurographics/ACM SIGGRAPH Symposium on Geometry Processing. SGP '04. Nice, France: ACM. pp. 175–184. doi:10.1145/1057432.1057456. ISBN 3-905673-13-4. Retrieved 1 December, 2013.
3. ^ Hansen, Glen A.; Douglass, R. W; Zardecki, Andrew (2005). Mesh enhancement. Imperial College Press. p. 404.