I often print at 1:1 to a physical printer and use the print by taping or gluing it onto material I need to drill or cut - works very well for small parts…
Recently I noticed that in actual fact the print is off by about 1 to 2 mm over 250mm.
I at first suspected rhino might be the culprit – Autocad (which I no longer use) apparently has calibration command which can be used to fix or minimise this kind of thing.
Anyway, I was getting the same kind of results from other cad software, so it wasn’t rhino.
I found after a little research online that it seems to be a common problem with many differing CAD software and printing, and there were many differing suggestions and ideas, but very little in the way of conclusive solutions.
A possible work around is to scale every 1:1 output from the cad software to adjust for the individual printer’s variation…
However, “all” it is is the actual printer itself. I was fortunately able to access three differing (brother) laser printers to test, feeding them all the same test file direct from rhino, and two of them were off by slightly different amounts (1.5 or so mm), and one of them was spot on.
For what it’s worth the one that worked well in this context was a brother HL-3070CW, although manufacturing tolerances probably mean its unlikely that all machines of this model printer will be this accurate.
Unfortunately, if the printer you have is not printing accurately, but otherwise fine, there seems to be little you can do to fix it, since it is not actually broken…
Of course for many users this kind of accuracy is not necessary, but if you are looking at buying a new printer, and it is important that it be capable of printing to scale accurately, I’d suggest running a test file on it, and measuring the output to check it is acceptable.