Very strange behaviour, perimeter tracking

[macua85 52]

Hi guys,

Im using Cura 15.02.1, and have been for some time now. However, a strange problem has recently developed. Whenever I print a part not, on each layer rather than taking the most direct route to the start point of the next layer, it tracks around (on top of) the perimeter. It ruining the prints, as a little plastic is dragging every time it does this. Is this a settings issue?

Thanks,

[eldrick 65]

You have probably got Combing turned on, - first item in Expert Settings.

[macua85 52]

I forgot to close this, just after I posted the question I found the combing feature. I was a little surprised that with combing off, the print time increases by 2 hours. I'd expect it to go the other way as the print head it taking to most direct routes. Is this normal?

Also, how about z hop, is it a feature worth using? When combined with combing, (or combing without perimeter), does it improve print quality and stringing?