Is Slic3r support slicing certain layer with different thickness? I would like to print the screw thread of a lens hood in 0.1mm thickness and 0.3mm for the rest, I think this can maintain the details and print faster.
Yes that's possible. Click on the part on the buildplate that needs different layerheight. Then click on settings. A new window opens with two tabs. One reads "layer". There you can tell slic3r which portion of the part needs a different layer height than the default height.
