The SDM engine and renderers create the nodes and links in the grapher, but the positions of these objects may not be ideal: some nodes may overlap and there may be too many link crossings, so that the resulting diagram can be difficult to apprehend.

When a graph layout renderer is declared, a graph layout algorithm positions the nodes and labels that are stored in the grapher and routes the links.

There are several algorithms: some just position nodes, others just route links, and some do both.

You need to choose from the various algorithms available, and your choice will depend on the topology of your diagram, and possibly on your industry. The many parameters will help you to tune the algorithm to fit your specific needs. You can use the Designer to help find the best solution.