Simplify3D User Forum

I cannot find anywhere where things like retraction distance, retraction speed are measured. Is 1mm retraction 1mm at the filment side or the nozzle side? If you have 1.75mm diameter filament and 0.5mm nozzle, then retracting the filament 1mm at the incoming (fat) side retracts it about 12mm at the nozzle (skinny) side.

I'm guessing from the numbers that all speeds/distances are at the nozzle end, and the software compensates for the ratio of filament diameter to nozzle diameter to calculate how much to move the extruder (which is pushing/pulling on the raw filament where it has the large diameter).

it is not the complicated.. the gear in the drive pull the filament back the amount that it is set to.. so direct drive has the gear right over the nozzle so .5 or .8 mm works fine.. with a remote drive (Bowden) the drive is a foot or more from the hot end with the filament in a plastic tube. When it pulls back it all flexes and does not do what is needed at the nozzle end (retract), so that is why you see big numbers for retraction with some printers vs other..