This RM Bridge FAQ: Influence surfaces example has a .pdf document and .tcl files to show how users can:
- use the influence surfaces for transversal analysis;
- use influence surfaces for the traffic load evaluation of wheel loads on grillages;
- create a mix of Macro2 and Macro3 within the generation of lanes for one surface;
- define a uniform load to be used at the influence surfaces;
- proceed if there are many load positions to be defined.
More basic information about Influence surfaces can be found at the link below:
communities.bentley.com/.../influence-surfaces