This feature is available in the submenu Extra in the context-menu. As described above, there are Additive Manufacturing machines that automatically fill your slices. If you decidedly don’t want any filling, it’s recommended to convert the contours into hatches. The contours now behave like the hatches of a filling and can’t be filled themselves again.
In the Hatch conversion dialog, you can perform the calculations either way: from contours to hatches or from hatches to contours. A high accuracy creates an exact calculation, but may lead to long calculation times.
It’s also possible to filter Contours/Hatches, which means that everything you have selected will be checked for certain parameters and those contours/hatches that fulfill the parameters will be copied. You can either preserve hatches and/or closed contours. Open contours can be retained too, but if you want to actually build them you’ll have to convert them into hatches afterwards.
Left: Part with hatches and contours, Right: after filtering with preserve hatches
The function Connect Contours is comparable to the Stitching in the Repair mode. Open edges that are lying close to each other will be connected. With Filter Small Contours, very tiny and unnecessary contours won’t be copied. You can define the Minimum Contour Area in cm³.