How to resize vector graphics using InkScape

[Revell-Fan]

Hello fans,

this tut should explain how to resize vector graphics using InkScape. You can do the same with any other vector program (like CorelDRAW), of course, but InkScape is the most versatile free alternative but has some "oddities" which will be mentioned here.

Many paper model plans come as PDF files. Resizing allows you to change the scale of the finished model and gives you the opportunity to free your model from the scale the original creator has given to it.

First it is important to see if the file you have chosen is suitable for this operation. To do so open the file and zoom in on the graphics. If they remain clear and sharp it is a vector, if it becomes fuzzy and blurry with steps and if you see compression artifacts the graphic is a bitmap. You can resize a bitmap graphic but this is not the subject of this thread.

Vector graphic:



Bitmap graphic:



My main weapon of choice is Corel because of its intuitive and straight-forward handling but it has trouble opening PDFs created after 2002 or so. This is why I have to use InkScape despite its weird behaviour. Sometimes InkScape has trouble importing / opening PDFs as well and tends to skip layers which unfortunately changes the look of the parts. If that happens you will have to use other methods (like turning the vector into a bitmap but this should always be your last option because it deteriorates the quality of the graphic).

Launch InkScape:



File > Open > choose the desired file and open it by hitting OK. If the PDF has several pages I reommend opening one page at a time and editing each page separately. That will make the process a bit easier.





If you open everal pages at once a series of pages will pop up in a row. You can clearly see that this reduces the space to navigate and makes selecting the components much more difficult:



So let's stay with the single page.

The next step is to reorganise the parts so that they can be moved around without losing information. I have no idea why the elements are organised like this but a careful preparation is important to achieve a successful result.

If you click on an element a frame appears:



Now you have to click Ctrl+Shift+G as many times until all elements have been ungrouped:



Sometimes a group is not ungrouped. You will notice that sooner or later (see below).

Then use the select tool and draw a rectangle around objects which belong together:



Press Ctrl+G to group them:



Move the part around a bit to see if you have grouped all necessary objects. If you see that a part of the element is not moved but stays in its place you will have to undo the movement, click on the element that did not move, ungroup it and group it with the other elements of the part to combine everything again. Then try and move it to see if you have got everything. This has to be done till all elements are grouped and combined.

Now go to File > New (or Ctrl+N) to open a new file.



Select all parts necessary (click on them while holding the ctrl key or draw a rectangle around them):



Ctrl+X > activate the new file window > Ctrl+V:



Move the parts onto the page:

 

[Revell-Fan]

Now close the proportion lock in the menu band and switch to %:



Enter the resizing factor and hit Enter:



Move the parts around so that they are all on the page. If a piece is too big move it aside for the time being:



File > Save as SVG or PDF to keep the vector nature. DO NOT EXPORT AS JPG, PNG, BMP OR ANY OTHER BITMAP FORMAT or all the previous work is in vain.

 

[Revell-Fan]

Resizing does not create a problem as soon as the template is scaled down. Upscaling can produce parts which do not fit on the page though:



In this case you have to cut it into manageable chunks which have to be joined after printing again.

To do so select the part and ungroup it:



Group some elements again which fit on the page and move them around:



You may add a flap on the page or later on the print to join the segments.

If the part is still too big you will have to manually cut it into parts:



There are two ways to do it.

1) If you need a quick solution draw a separation line across the part. Move the line below the part:

select the line > object > move to the bottom:



Group everything and create a duplicate (Ctrl+A > Ctrl+G > Ctrl+D). Arrange the parts so that both halves are on the page:



You may add white rectangles on top of the parts with the lines as alignment marks to save on ink and to get some "visible white space" which you can fill with other parts to save paper. It is best to group the duplicate parts and their respective white areas so that they are not shifted accidentally:



2) A more elegant solution would be to cut the shapes into halves and move those around. This would eliminate the need to work with a white piece or a line. However, this would require more editing which would be the topic of another tut.

 

[Revell-Fan]

A few thoughts about the line thickness

InkScape provides a button which enables you not to affect the line thickness during resizing. If you uncheck the button 1 pix outline of a part will be 1 pix wide on the resized version:



However, if you have a sophisticated texture which depends on true to scale line thicknesses in order to look right it is necessary to resize the line thickness proportionally, meaning a 1 pix wide original line will be 3 pix wide on a 300 % enlarged version. To achieve that you have to check the "Resize line thickness" button in the top menu:



You can immediately see that the line on the rescaled object is much thicker now. Whereas this may be a benefit for the texture it might affect the outline of the object itself in a bad way. Slight increases may be tolerable but noticable amounts may make it look out of place and bloated. A model with too thick outlines may look cartoony and strange in the end. So it may be necessary to adjust the outline of a rescaled object before printing to improve the result. To edit the outline select (click on) the object you want to edit (ungroup it first, that may make things easier, or keep pressing Ctrl and then click on the part with your mouse), double-click on contour in the lower left menu, go to contour pattern and enter the desired line thickness value:

 

[mijob]

Thats a lot of information thanks for sharing with us.