After a few failed attempts in the past I am back onto my track project.
I have started from scratch again & have pretty much got to the same point as before.
Hoping that autocad would help with the sections' info/data (radius,length,curvature) I find that it doesn't (really) help!
I traced the centreline of the track in cad & created the sections accordingly. As mentioned, sadly cad didn't miraculously solve the gtk side & the end doesn't meet the start of the lap.
I am using gpltrk as I cannot get the background image to load/work in gtkmaker (neither on win7 32 nor xp sp3)
I have overlaid an image of my gtk onto a map of the track & can see the problems but I don't know how to adjust whichever section to correct the layout.
Is it a question of adjusting the curvature of a section (by trial & error) then zeroing the following sections until it looks right or is there a way to calculate the required change?
any advice welcomed