help with correct scaling set up

[TravelingMan]

Hi everyone, Scaling has always totally confused me. so here is what I want to do. I am redisigning my dashboard in our motorhome. I want to draw the rectangle that is the instrument area and measures 550mm wide and 210mm high so that it will print on a A4 piece of paper. I need to be able to draw various size circles for the instruments etc.

I cannot work out the maths for setting a scale in document properties that will work. I know that is probably so elementary but sometimes the brain just refuses to work.

Would appreciate any help please

[Moini]

Okay, so you want 550 to become 297 (which would be the exact height of A4), and 210 to become 297/550 * 210 (=113.4). So you'd be scaling by *0.54 .

I don't understand why you want to set a scale, though. What do you need that for? Can't you just use a larger page size? You can export two pictures and print them separately, or just move your picture before printing. Only the page area will be printed. Or you can print to A4 and tell your printer to shrink the drawing to fit the page.

The more common way to scale a drawing to fit the page would be to just hold down Ctrl, and use the selection tool to scale the item in the drawing until it fits on the page (maybe in conjunction with snapping to page corners). It can be scaled to any other size later, whenever you need to. You can enter numbers for width and height in the tool controls for the selection tool. You can lock the width/height ratio by clicking on the lock icon.

Anyway, I think there's some important detail missing here that tells us what exactly you want, and why you want to change the drawing's scale.

[brynn]

Anyway, I think there's some important detail missing here that tells us what exactly you want, and why you want to change the drawing's scale.

I think she means, for example, do you need to send the file to a digital cutter or plotter, or maybe 3d printer or other special printer (other than what's connected to your computer).  If so, see this:  https://inkscape.org/en/learn/faq/#inkscape-092-my-drawings-are-just-quarter-their-original-size-when-i-open-them-program-xyz

Assuming you mean that you want to print on the printer connected to your computer, then it's lucky for you that you want to work in mm (because Inkscape is now set up to use mm natively) (causing all sorts of confusion and problems for all sort of user groups who don't want to use mm) (unnecessarily, imo).

Here's what I would do.  Look in Edit menu > Inkscape Preferences > System, and find out where your preferences.xml file is located (User Preferences).

Close all instances of Inkscape, go to that location and delete the preferences.xml file.  (This will get rid of any and all changes you've previously made.)

Open Inkscape, and don't touch the Display Units or Scale options, in Document Properties.  It's already set for mm.

Draw a rectangle of some specific size.

Print it out and measure the printed rectangle, to find out how closely Inkscape and your printer are matching.  As far as I understand, printers can have their own resolutions, which....  Well from the last time I tried to print something from a computer, the printer's resolution was different from Inkscape or my computer screen.  From what I've heard this is not just common, but pretty much expected.

Anyway, after you do that, then post again, and tell us the results of the test.  Then someone else can tell you what to do. 

I have no idea, but I'm pretty sure the solution is not going to be changing the Scale setting in Inkscape.  Maybe you would adjust your printer's resolution?  Or maybe you would just scale the objects in Inkscape, since now you can figure out the needed scale factor.

[Moini]

@brynn: if it was smaller, that might be due to the printers unprintable margins. The picture that will be printed is shrunk until it fits into the print margins of your paper sheet (if you choose 'fit to margins' or whatever your print software supports).

[TravelingMan]

Thanks for the replies. I might not be doing things the right way. Ok so its not printing thats the issue its me being able to accurately plan the layout. So if I draw the board whatever i use to size it, must represent the real world size. And if I draw a guage of 52mm dia it must also be accurate in scale, so I can move the various guages around until I am happy with the layout.
Then by using dimensions I can measure in both vert and horiz from edges to pinpoint centres in order to create the holes. Or use a grid perhaps.
I think this used to be easier with graph paper, ruler and pencil. Lol (guess what generation I belong to lol)
However in saying that, printing a full size drawing even over a number of pages could be very useful. I hadn't even though of that.
Told you I am not used to this stuff.

[brynn]

Oh don't worry, I'm with the pencil and graph paper generation too!  Typewriters, books, I probably even have a slide rule somewhere (although to be honest, it was my dad's and I never used it).  (omgoodness, and don't get me started how computers have massacred spelling and punctuation!)

The biggest change that you have to get used to, is that with pencil and paper, you typically start measuring things before you start to draw.  In Inkscape, you draw something first, and then make it the right size.  If there's some reason you need to measure first, there are ways to do it, but they aren't obvious for beginners.

So let me just clarify this.  At first you said you needed to print on an a4 paper.  Are you saying now that you don't need any output.  You're not going to print, or send it to a cutter, or 3d printer or anything.  You don't need any physical object as a result, and it will all be on the computer screen.  Right?

In that case, does it really matter if the whole area is precisely, 550 mm x 210 mm in real world units?  As long as everything is in the correct proportion, you can get what you need without the headache of creating real world sizes.

Given all the changes you mentioned trying earlier, it sounds like you might have changed something that would cause trouble.  So I still suggest the process I outlined above, about closing Inkscape, deleting preferences.xml, and opening Inkscape again.  Then don't touch the Display Units or the Scale settings.  Everything is perfect for you already.  The canvas and rulers, and all the tools are set for mm.

Then, just start drawing.  Actually....did I already say this?  I would suggest looking at Help menu > Tutorials > Basic.  And also the 2nd one, Shapes.  And maybe even the one titled "Advanced" although it really isn't all that advanced.  It's a beginner's introduction to paths.  Those 2 or 3 will get you familiar with most everything you will need.

Or you could also look on the Home tab (our huge lists of links to tutorials all over the internet) in the Beginner Skills block.  Some videos there, if you prefer.