How to make parts:
This is how I do it....looks simple !!...and it is, just work with styreen like making a cardboard version it's exactly the same, if you look at it you see it's made up of seperate boxes.
and you can use a simple hobby knife ( I use a surgeon's knife as it has a thin blade )this parts is completely made of styreen sheet 1,2 and 3mm.
first I map out an the drawing witch parts are going to be what thickness the how the parts are going to be glued to each other.
The first basic shapes are cut and the support structure is made between it, I used the 2mm for the flat shapes and 1mm for curved surfaces, and the 3mm is used for reinforcing parts.
lots of parts are made over sized and can easily be sanded to their correct shape afterward (no need to cut exact size !!!).
for the lower part I used tubes and glued the half way in and sanded them flat.