Plan Printing

* It is your responsibility to have proper virus scanners and firewalls in place before downloading and opening files from the internet, there are some mean people out there who hide viruses (and worse) inside downloaded files.

There are 4 main types of file format you will most likely come across:

Raster (jpg, gif, bmp, png, tif) - Essentially the difference is Raster files are made up of fixed sized dots called pixels, where each pixel can be a different colour and shade. The problem with scaling these files is down to the fact that it’s the dots you are making bigger, this is why a small picture when enlarged goes a bit fuzzy, and why on TV the forensic team can never recreate a full colour photo from half of a dark CCTV image!

Vector - These use a mathematical relationship between the points with lines connecting the points, so scaling becomes a matter of maths, not just making the pixels bigger and its precisely this difference that make vector images scale nicely while rasters don't.

DXF - These are proper computer aided design (CAD) files. They can be opened and edited with programs such as the high-end AutoCAD (who developed the format), the more reasonably priced DevCad ( or with one of the many viewers available for download.

PDF (portable document format) - These are proprietary to Adobe, and can either Vector PDF or Raster PDF with no easy way to differentiate between the two unless you open them and see how well they scale once opened with Adobe Acrobat. You cannot edit unless you have the full Acrobat product.

It is possible to convert between file formats. For your homework (or iStudy as my son now calls it) search the internet for information on how to do this if you are interested.

PDF Printing - PDFs are awkward to print unless you have the full version of Adobe Acrobat. Again an internet search on 'PDF tile print' will give you lots of info to keep you busy and it will also include some free tools to help.


The term 'tile print' means to take the plan image file and print sections of it on a sheet of A4 and then piece the tiles together to produce a working plan. An internet search of 'tile printing' will return too much info to discuss here (more homework) so I'll be looking at IsiPlot from Stefan Duranti. However be careful not to upset him, as he'll stop you from buying anymore of his products - as has happend to me. So no more products reviews :-(. Still glad to see business is going so well.

That said, his application is an absolute joy to use. Its strength is in its ease of use and simplicity. Simply load the image file, scale and print.

Calibrate Raster
Press the ‘Calibrate Raster’ button, draw a line between 2 points, a wingspan (or wing panel) and in the Calibration window that pops up type the value and select the units. That’s it.
Tile Example

IsiPlot - Tile Example – note the alignment marks in the 4 corners to help piece the plan together.

The registered version will allow you to print DXF, .BMP, .GIF, .TIF, .JPG files. There is no support for PDF files though.

You can download a trial version with some restrictions from the IsiPlot website at At the time of writing registration is 10 Euros which is an absolute steal when you consider there is also a good selection of plans for free download to get you going. Look for the ‘Plans and Drawings’ link in the left menu.

For the more ambitious who might like to try their hand at designing models, Stefano has other great applications, namely DevCad and DevFus. Just follow the links on his website, but heed the warning above or you could be left out in the cold.

To my mind the best bit

There are two tasks that are not entirety obvious:

First, the fact that you can put any number for the scale, which means you can print the plan out at any size. But beware of the obvious pitfalls in that wood sizes may not match and the structural integrity of the model may need beefing up if you go too big. Likewise you could take some material out if you are going smaller to save weight. Experience is the only advice I can offer here.

Secondly is the ability to select a portion of the plan and just print the selection. This is ideal for additional prints for formers and ribs etc. Should you mess one up, just print another.

Another technique I’ve used is to use standard 80g paper, cut the parts roughly and oversized. With photo mount spray, stick the parts to the wood and cut through, then peel off the print. You can keep the printing attached until the part is needed to help with identification.