First, select a graph

Random (1K edges)
US Airlines (1K edges)
US Migrations (10K edges)
GraphML file:

Then, bundle!

Bundling criteria

Sigma

Step

Edge smoothing

Initial separation

Repellence

Finally, adjust rendering

Invert colours

Weight edges

Edge alpha

3DHEB - 3D Histogram-based Edge Bundling

by Daniel C. Moura. Built with Processing and Processing.js

Simplified version of the 3DHEB bundling algorithm described here.
If you use this software or images generated by this software, please give me credit by citing the following work:

@ARTICLE{moura2015_3dheb,
   author = {{Moura}, Daniel C.},
    title = "{{3D} Density Histograms for Criteria-driven Edge Bundling}",
  journal = {ArXiv e-prints},
   eprint = {1504.02687},
     year = 2015,
    month = apr
}

Also, check out this video created with 3DHEB: vimeo.com/danielcmoura/3dheb!