Unless something has changed - here is what I know
- the svd svl or dsz format breaks up all linework into squares of I believe 50m or 50’ - it loads 9 squares of data around the machine at all times - the machine square, one ahead, one behind, one left and one right and then the 4 corner squares. It loads and unloads data as the machine moves from square to square. This goes back to Sitevision which ran on a box with next to zero memory and so data had to be managed effectively. The map otherwise is an image I believe.
The lines are broken by TBC because that is the definition of the file types in use. However the machine knows this and will connect the lines over these breaks or it should do - if you reinsert an SVD SVL the lines are broken in tbc but in the machine this should not have any effect on line selection for guidance
Second - the machine when it reads the lines - if it finds lines that cross each other eg a Centerline Nd centerline label ticks for example - the machine breaks the lines at all crossings - same would apply to curb and contours for example. If this is the issue them you have to use eg crop crossing to break out a section of the ticks or contours either side of the lines you want to use for guidance - then the machine doesn’t see the crossings and doesn’t break the lines.
I have tested this in the past and validated with the machine simulator to prove this to be correct
Unless something changed or Unless works manager is not prepping the files correctly from the VCLs it is given then I think this is correct - however I am pretty sure that WM is not breaking out the crossings- you have to do that in TBC