Omni Commons has three stories (basement, ground floor, and second floor).
The total area of the building is approximately ~22,418 ft2 (square feet) (summed by floor, respectively:
4799.84375 + 12300.6875 + 5317.25 = 22417.78125), which is ~2083 m2 (square meters).
Drawings of the Building
Below are detailed drawings by Rod Lamkey (Design Services) as of January 11th 1996. Lots of details and dimensions, but a bit hard to read in places. Here's the original file.
And cleaned up versions of the same file:
The following floorplan images have been annotated with corresponding names/numbers for the logical sections of the building. A full composite plan is provided, along with a file for each floor. The individual files should be sized 1 pixel to 1 inch.
Usage floorplan (non-architectural, draft)
Proposals of Usage
Omni Commons Calendar (Occupy) Floorplan
Draft Initial Proposal
This spreadsheet contains an estimate of the size and features of the spaces, based on name/number: https://docs.google.com/spreadsheets/d/17DINigEczGwjfTdmdxl-MpYe1KJzJJDeCHRQnMC9usg/edit#gid=1418749855
You should be able to easily edit the "svg" version using Inkscape, available on every platform (Windows, Mac, Linux).
Draft Initial Proposal - NS
Another possible plan for space allocation
Draft Name Proposal