A few days ago I started to learn Altium Designer 17 and immediately stumbled upon some strange behavior. I created my first component and decided to see how it will look on paper. So I added this component to a schematic sheet, set the sheet size to A4 (look at the screenshot below), tried to print it, and… got not what I expected.
I began to look for the causes and noticed that the sheet on my screen has the wrong proportions! Approximately 0.66 instead of 0.707 for A4. When I ticked "Use Custom Style" and set all the sizes manually, the problem was solved. Okay, that's good, but why the standard style called A4 doesn't work? I tried to do the same thing in Altium 18 and got the same result.
It is interesting that in the "Tools->Schematic Preferences" dialog you can set the default sheet size. If you set this size to A4, the parameter called "Drawing Area" becomes equal to 292x193mm, which gives us this weird 0.66 ratio. So… This is not a bug. But what is it?
To make it more clear I made a screenshot. Here is my schematic sheet. In the document settings, the size of the sheet is set to A4 (see the first picture in my question). According to the standard, A4 has 0.707 height/width ratio, but neither A/B nor D/C equal to 0.707!
Best Answer
Printing is different from the (virtual) document size. The schematic document size sets the proportions and the mapping from the symbol size to document.
The printed page dimensions and scaling are set by File->Page Setup. You probably would want to set the two the same. The default is probably 'letter' (215.9mm by 279.4mm) not 'A4' (210mm by 297mm).
Edit: You can see the print area by right-clicking in the preview pane and selecting appropriate options. The available area changes with the selected printer. It does appear that, for whatever reason, they've chosen to make the aspect ratio a bit different from that of the paper, leaving a few mm more space top and bottom.
Of course when you make your own template (which you would definitely want to do, to include your company logo and your custom title block) you can alter it if you want.