Clamp Ironing Line Spacing to a Usable Minimum (#15949)

An ironing line spacing of 0 reached the fillers from a 3MF, the CLI or the per-filament override, which has no GUI guard. Concentric ironing then never finished slicing, because a zero inset never shrinks the region, and rectilinear ironing was silently dropped. Tiny positive values produced an unprintable number of lines. Top surface and support ironing now clamp the spacing to the 0.05 mm floor the process GUI guard already enforces, so these configurations iron at that spacing. Spacings at or above the floor, including every shipped profile, are unchanged. The concentric filler also returns early on a non-positive step so no other caller can hang it, and the filament settings page now resets a too-small override the same way the process page does.
2026-10-14 11:21:18 +00:00 · 2026-10-01 16:53:16 +08:00
parent 3384daa6bc
commit 92d30fbc55
8 changed files with 95 additions and 5 deletions
@@ -748,6 +748,61 @@ TEST_CASE("A region with ironing turned off is never ironed", "[Fill]")
    REQUIRE(Layer::choose_ironing_extruder(cfg, spiral_mode, /*is_topmost_layer=*/true) == -1);
 }

+// Ironing path count and total length in mm, over the whole object.
+static std::pair<size_t, double> ironing_extent(const Print &print)
+{
+    size_t paths  = 0;
+    double length = 0.;
+    for (const Layer *layer : print.objects().front()->layers())
+        for (const LayerRegion *region : layer->regions())
+            for (const ExtrusionEntity *entity : region->fills.flatten().entities)
+                if (ironing_role(entity->role())) {
+                    ++paths;
+                    length += unscale<double>(entity->length());
+                }
+    return {paths, length};
+}
+
+TEST_CASE("Ironing spacing below the minimum irons at the minimum spacing", "[Fill]")
+{
+    const std::string pattern      = GENERATE("rectilinear", "concentric");
+    const bool        via_filament = GENERATE(false, true);
+    const double      spacing      = GENERATE(0., 0.001);
+    CAPTURE(pattern, via_filament, spacing);
+
+    auto ironing_for = [&pattern, via_filament](double spacing) {
+        DynamicPrintConfig config = DynamicPrintConfig::full_print_config();
+        config.set_deserialize_strict({{"ironing_type", "top"},
+                                       {"ironing_pattern", pattern},
+                                       {"layer_height", 0.2}});
+        // The filament override replaces the process spacing, which stays at a usable value.
+        if (via_filament)
+            config.set_deserialize_strict({{"ironing_spacing", 0.1}, {"filament_ironing_spacing", spacing}});
+        else
+            config.set_deserialize_strict({{"ironing_spacing", spacing}});
+        Print print;
+        Slic3r::Test::init_and_process_print({Slic3r::Test::cube(20)}, print, config);
+        return ironing_extent(print);
+    };
+
+    const std::pair<size_t, double> clamped = ironing_for(spacing);
+    const std::pair<size_t, double> minimum = ironing_for(IRONING_SPACING_MIN);
+    REQUIRE(minimum.first > 0);
+    CHECK(clamped.first == minimum.first);
+    CHECK_THAT(clamped.second, Catch::Matchers::WithinRel(minimum.second, 1e-9));
+}
+
+TEST_CASE("Concentric fill at zero spacing returns without paths", "[Fill]")
+{
+    std::unique_ptr<Fill> filler(Fill::new_from_type(ipConcentric));
+    filler->spacing      = 0.;
+    filler->bounding_box = BoundingBox(Point(0, 0), Point::new_scale(10, 10));
+    FillParams params;
+    params.density = 1.f;
+    Surface surface(stTop, ExPolygon({Point(0, 0), Point::new_scale(10, 0), Point::new_scale(10, 10), Point::new_scale(0, 10)}));
+    CHECK(filler->fill_surface(&surface, params).empty());
+}
+
 TEST_CASE("Solid infill direction offsets every layer when no template is set", "[Fill]")
 {
    auto angles_for = [](int direction) {