Substance Source: Edit and Study Graphs

The idea behind releasing the .sbs files in Substance Source is that texture designers should not be limited by the presets available within the .sbsar files. The graph’s fully adaptive structure gives you the opportunity to make any changes and transformations you need beyond the original setups. From modification of a few nodes to making new textures from a graph template, you don’t have to create new materials from scratch.

You can find more on the open source initiative here.