Add lift_min: minimum height to travel between objects

Also change other behaviors to be compliant:
 * At the first move don't split the travel
 * At the first move, if start_gcode_manual and no layer_gcode, don't lift the nozzle so the printer won't "z-dance", whatever where the nozzle is.
Note:it's a hack, please redo it properly when reworking gcode-writer.
 * retract_lift_first_layer is gone back to the old simple behavior (revert b16ecbfc)
 * removed auto extra lift for first layer, now that lift_min exists.
 * with complete_object, don't unlift at object/first layer change, to avoid Z-dance
 * lift_min will be used between brims, skirts, objects but not between object-skirt, object-brim and their object
supermerill/SuperSlicer#1783
supermerill/SuperSlicer#1775
supermerill/SuperSlicer#1575
supermerill/SuperSlicer#599
supermerill/SuperSlicer#429
supermerill/SuperSlicer#395
supermerill/SuperSlicer#241

1 files changed, 1 insertions, 1 deletions

diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 9db946043..0e3375df3 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -2965,7 +2965,7 @@ void TabPrinter::toggle_options()
 
         // retract lift above / below only applies if using retract lift
         vec.resize(0);
-        vec = { "retract_lift_above", "retract_lift_below", "retract_lift_top" };
+        vec = { "retract_lift_above", "retract_lift_below", "retract_lift_top", "retract_lift_first_layer" };
         for (auto el : vec) {
             field = get_field(el, i);
             if (field)