Substance 3D Designer is a Material and 3D Model authoring software. It generates textures from procedural patterns or by manipulating bitmaps inside a node graph as well as generates 3D models.

In short, Substance 3D Designer should be seen as the most technical, advanced texturing application available. It allows you to author content for almost any use case or scenario. It means you are not limited to a single type of output (such as a unique material/set of textures for a UV-mapped mesh) but can create content for a much more extended set of uses. For example, most of the procedural, smart content in Painter and Sampler was authored and exported from Designer. Things like Brush Alphas, Generators, Filters, and Base Materials can all be authored in Designer.