FTM can export a chart as a one-page PDF file to be taken/emailed to a commercial firm with large format printers e.g. AO size or above.
Unfortunately, because FTM uses a very early version of PDF, (version 1.3) the chart size limit is 5 metres (about 200 inches). So if you go above that, then the chart will be truncated. Yes, it is disappointing that one part of FTM can produce large charts whilst another bit then truncates them. And we have had this situation for years and there is an existing solution !!%$#@
Yes, the developers know all about the issue but the supplier of the Share module that includes the PDF driver will/has not updated the PDF version. Later versions of PDF removed the 5-metre limit and in terms of FTM charts, it is “unlimited”.
Now as to the number of generations you can fit on [say] AO paper depends on how you set up the chart, e.g. font size, items includes, whether you use short place names etc. As with all charts, you have to do some trial and error fiddling to optimize them. Of course once you have done that you can save any chart for reuse and also save the template for reuse in other charts
So if you have a chart above 5 metres there are some workarounds
You can use an outside chart application called Charting Companion http://progenygenealogy.com/products/family-tree-charts/fami...
Or Family Tree Factory http://www.family-tree-factory.com/
Both can produce very large charts from FTM (Charting Companion) or from a GEDCOM (Family tree Factory)
Both programs will then convert the large chart to PDF (without the 5 metres limit). You can take the PDF file to a printing company that specializes in large charts.
Another workaround is to install a PDF creator such as Adobe Acrobat (not the Adobe Reader) and "print to PDF" from FTM. There are other PDF creators like Nitro, PDF995, etc as well to consider.
So up to 5 metres you can stay inside FTM and produce a PDF file that can be printed on a large printer/plotter. Above that you need to go outside FTM