Having owned a laser cutter for nearly 10 years , I have found that most old hand drawn plans are inaccurate and a lot of the old die cut kit parts are not only inaccurate but in most cases the bulkheads for instance are asymmetrical.
When making a model you have to first correct the bulkheads etc (not difficult using Corel) and then cut a prototype to determine what further errors there are. Back to the drawing board to correct those, and then a further test cut etc. In the early days it would take about 6 versions
to correct all the errors , but with experience have now whittled it down to about 3 as areas likely to have errors can be anticipated. There is also the difficulty of for instance "3mm" thick material that can vary from about 2.7mm to 3.4mm and that can mean parts don't fit.
Having said that I have cut most of the EezEbilt models
from the site and the errors are minor besides being balsa they are easy to correct especially using water-resistant quick drying PVA glue. With enlarged versions
you have to correct the slots etc so its easy enough to check on Corel for any inaccuracies. (That is one of the beauties of digital plans - you can produce a model at any size you choose). Most Lasers
use dxf CAD files which Corel converts for you either way importing or exporting. One of the drawbacks my partner and I see is that in CAD drawings a curve is represented by a large number of straight lines which makes for a very large file. In Corel a curve is simply a curve and hence a much smaller file.
PDF files are very problematic for most modellers as for instance two files imported from the same source can vary in size dramatically and you then have parts that don't match. The same applies to printing pdf plans in parts on an A4 printer
- the pages very often don't line up. JPG files are much less of a problem as sizes go.
My personal feeling is that the mismatch of parts is probably due to the use of pdf files with their associated problems. Some printer
s unfortunately do not allow you to adjust sizes other than in a rudimentary fashion.