We have developed a simple tool using Ram Data Access that can add grid lines to an existing model at the column locations, and optionally at wall end locations. This is especially useful when working on RAM Structural System models that were imported from CAD, Ram Concept or ISM that for whatever reason do not have any grids already. It can also be used with models that have some grids, but not at all locations.
The tool is a macro enabled Microsoft Excel spreadsheet available here (sign in is required):
Here is a short video of the the tool in use.