1. A computer system for designing a floor plan of an integrated circuit (IC) design to includes a preliminary route plan, the computer system comprising: a user interface; a memory subsystem that stores a representation of at least a portion of the IC design and computer code for designing a floor plan; and a processor subsystem, the processor subsystem programmed to: generate a floor plan having multiple blocks of logic and channels comprising portions of one or more layers of metal extending between the blocks; determine a supply of routing resources that is available for one or more selected channels of the floor plan for routing electrical signals in the selected channels between the blocks; generate a preliminary route plan in the floor plan for the selected channels based on the supply of available routing resources, the preliminary route plan comprising electrically-conductive routes, each selected channel including at least one of the routes; determine a demand on routing resources for each respective selected channel based on the preliminary route plan; determine whether or not the demand on routing resources for each respective selected channel exceeds the supply of routing resources for each respective selected channel; and a display system comprising at least one display device, wherein if the processor subsystem determines that the demand on routing resources for a respective selected channel exceeds the supply of routing resources for the respective selected channel, the computer system causes a visual indication of the excess demand to be displayed on the display system.