mesh import fit ignores far-off stray pieces (with hint), project load warnings with readable names, edit projects of imported levelbuild wads load again (header runs applied to original values), -0.0 kept in saved arrays; start cameras checked in game on the test world and a village 2 base

src/main/java/com/eliasmueller/llamamod/editor/io/NodeCodec.java

@@ -20,6 +20,7 @@ import java.util.Map;
  */
 final class NodeCodec {
     static final int INLINE = 64;
+    private static final long NEG_ZERO = Double.doubleToRawLongBits(-0.0);
 
     private NodeCodec() {}
 
@@ -54,7 +55,9 @@ final class NodeCodec {
     }
 
     private static Object doubles(double[] a) {
-        if (a.length <= INLINE) {
+        // JSON numbers lose the sign of -0.0 (imported models have it; it changes the built bytes)
+        if (a.length <= INLINE
+                && java.util.Arrays.stream(a).noneMatch(x -> Double.doubleToRawLongBits(x) == NEG_ZERO)) {
             List<Object> l = new ArrayList<>(a.length);
             for (double x : a) {
                 l.add(x);

src/main/java/com/eliasmueller/llamamod/editor/io/SceneDiff.java

@@ -7,6 +7,7 @@ import com.eliasmueller.llamamod.editor.model.NodeKind;
 import com.eliasmueller.llamamod.editor.model.NodeList;
 import com.eliasmueller.llamamod.editor.model.Prop;
 import com.eliasmueller.llamamod.editor.model.PropType;
+import com.eliasmueller.llamamod.editor.model.ReadableNames;
 import com.eliasmueller.llamamod.editor.model.Scene;
 import com.eliasmueller.llamamod.editor.model.TexturePage;
 import com.eliasmueller.llamamod.editor.model.cmd.Values;
@@ -15,6 +16,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 
@@ -154,6 +156,8 @@ final class SceneDiff {
         Map<String, Object> nodes = (Map<String, Object>) json.getOrDefault("nodes", Map.of());
         // 1. removals, 2. create added nodes (all kinds, so references resolve), 3. set values
         List<Map.Entry<Node, Map<String, Object>>> fill = new ArrayList<>();
+        // per-node problems, named once the level order is final (readable names are numbered by it)
+        List<Map.Entry<Node, String>> nodeWarn = new ArrayList<>();
         for (NodeKind k : Scene.LIST_KINDS) {
             Map<String, Object> d = (Map<String, Object>) nodes.get(k.prefix());
             if (d == null) {
@@ -162,7 +166,7 @@ final class SceneDiff {
             for (Object id : (List<Object>) d.getOrDefault("removed", List.of())) {
                 Node n = s.node((String) id);
                 if (n == null) {
-                    warn.add("removed " + id + " does not exist in the base level");
+                    warn.add("The project removes " + aKind(k) + " that is not in the base level – ignored");
                 } else {
                     s.remove(n);
                 }
@@ -171,7 +175,7 @@ final class SceneDiff {
                 Map<String, Object> m = (Map<String, Object>) o;
                 String id = (String) m.get("id");
                 if (s.node(id) != null) {
-                    warn.add("added node " + id + " already exists – skipped");
+                    nodeWarn.add(Map.entry(s.node(id), "the project adds " + aKind(k) + " in its place – skipped"));
                     continue;
                 }
                 BrushKind bk = k == NodeKind.BRUSH ? BrushKind.valueOf((String) m.get("brushKind")) : null;
@@ -183,7 +187,7 @@ final class SceneDiff {
             for (Map.Entry<String, Object> e : ch.entrySet()) {
                 Node n = s.node(e.getKey());
                 if (n == null) {
-                    warn.add("changed " + e.getKey() + " does not exist in the base level");
+                    warn.add("The project changes " + aKind(k) + " that is not in the base level – skipped");
                     continue;
                 }
                 fill.add(Map.entry(n, (Map<String, Object>) e.getValue()));
@@ -198,6 +202,12 @@ final class SceneDiff {
         for (Map.Entry<Node, Map<String, Object>> e : fill) {
             Node n = e.getKey();
             Set<String> known = new HashSet<>(List.of("id", "brushKind"));
+            // array runs are relative to the base value: read them all before a setter clears one
+            // (setting a model's vertices clears its header)
+            Map<String, Object> before = new HashMap<>();
+            for (Prop p : n.props()) {
+                before.put(p.name(), p.get(n));
+            }
             for (Prop p : n.props()) {
                 known.add(p.name());
                 if (!e.getValue().containsKey(p.name()) || !editable(p)) {
@@ -211,17 +221,17 @@ final class SceneDiff {
                         && pm.containsKey("png")) {
                     byte[] png = assets.get((String) pm.get("png"));
                     if (png == null) {
-                        warn.add(n.id() + ": page image " + pm.get("png") + " missing");
+                        nodeWarn.add(Map.entry(n, "page image " + pm.get("png") + " missing"));
                         continue;
                     }
                     v = Images.pagePixels(png, pg.width(), pg.height());
                 } else {
-                    v = NodeCodec.decode(p, j, s, p.get(n));
+                    v = NodeCodec.decode(p, j, s, before.get(p.name()));
                 }
                 try {
                     p.setRaw(n, v);
                 } catch (IllegalArgumentException ex) {
-                    warn.add(n.id() + "." + p.name() + ": " + ex.getMessage());
+                    nodeWarn.add(Map.entry(n, propLabel(p) + ": " + ex.getMessage()));
                 }
             }
             for (Map.Entry<String, Object> f : e.getValue().entrySet()) {
@@ -254,5 +264,20 @@ final class SceneDiff {
         for (var st : s.strats()) {
             st.setTypeName(s.catalog().nameOf(st.code()));
         }
+        ReadableNames names = ReadableNames.of(s);
+        for (Map.Entry<Node, String> w : nodeWarn) {
+            Node n = w.getKey();
+            warn.add((n.scene() == s ? names.nameOf(n) : ReadableNames.name(n)) + ": " + w.getValue());
+        }
+    }
+
+    /** "an object", "a tile model". */
+    private static String aKind(NodeKind k) {
+        String l = k.label().toLowerCase(Locale.ROOT);
+        return ("aeiou".indexOf(l.charAt(0)) >= 0 ? "an " : "a ") + l;
+    }
+
+    private static String propLabel(Prop p) {
+        return p.label() == null || p.label().isEmpty() ? p.name() : p.label();
     }
 }

src/main/java/com/eliasmueller/llamamod/editor/tools/geometry/MeshImportDialog.java

@@ -52,6 +52,7 @@ final class MeshImportDialog extends JDialog {
     private final Preview preview = new Preview();
     private final JLabel info = new JLabel();
     private final JLabel warn = new JLabel();
+    private final JLabel fitHint = GeoWidgets.hint(" ");
     private final JComboBox<String> up =
             new JComboBox<>(new String[] {"Y up (glTF, most OBJ)", "Z up (some CAD exports)"});
     private final JSpinner unit;
@@ -100,6 +101,7 @@ final class MeshImportDialog extends JDialog {
                 GeoWidgets.row(new JLabel("Up axis"), up),
                 GeoWidgets.row(new JLabel("Unit scale (file units → cells)"), unit),
                 GeoWidgets.row(new JLabel("Largest side"), fit, new JLabel("cells"), fitB),
+                fitHint,
                 GeoWidgets.row(new JLabel("Turn"), turn, mirror),
                 GeoWidgets.row(ground)));
         form.add(GeoWidgets.section(
@@ -196,22 +198,50 @@ final class MeshImportDialog extends JDialog {
         if (m == null) {
             return;
         }
-        double[] b = m.bounds();
-        double size = Math.max(b[3] - b[0], Math.max(b[4] - b[1], b[5] - b[2]));
-        if (size <= 0) {
-            return;
+        double us = fitScale(((Number) unit.getValue()).doubleValue(), m.positions(), cells);
+        if (us > 0) {
+            unit.setValue(us);
         }
-        double us = ((Number) unit.getValue()).doubleValue() * cells / size;
-        unit.setValue(us);
+    }
+
+    /**
+     * Unit scale that makes the largest side of the mesh's main mass ({@link Preview#focusBounds}) {@code
+     * cells} long; 0 for an empty or flat-point mesh. {@code pos} is in cells at the current {@code unitScale}.
+     */
+    static double fitScale(double unitScale, double[] pos, double cells) {
+        double size = largestSide(Preview.focusBounds(pos));
+        return size > 0 ? unitScale * cells / size : 0;
+    }
+
+    private static double largestSide(double[] b) {
+        return Math.max(b[3] - b[0], Math.max(b[4] - b[1], b[5] - b[2]));
+    }
+
+    /** Hint shown under "Largest side" when far-off pieces are left out of Fit; empty otherwise. */
+    static String fitHintText(MeshData m) {
+        double[] f = Preview.focusBounds(m.positions());
+        double[] b = m.bounds();
+        if (largestSide(f) >= largestSide(b) - 1e-9) {
+            return "";
+        }
+        return String.format(
+                Locale.ROOT,
+                "Fit ignores far-off stray pieces: main part %.2f × %.2f × %.2f cells.",
+                f[3] - f[0],
+                f[4] - f[1],
+                f[5] - f[2]);
     }
 
     private void update() {
         MeshData m = asset.mesh();
         if (m == null) {
             info.setText("(no mesh)");
+            fitHint.setText(" ");
             return;
         }
         double[] b = m.bounds();
+        String fh = fitHintText(m);
+        fitHint.setText(fh.isEmpty() ? " " : fh);
         int textured = 0;
         for (MeshData.Material mt : m.materialList()) {
             if (mt.image() != null) {
@@ -444,7 +474,8 @@ final class MeshImportDialog extends JDialog {
 
         /**
          * Bounds {x0, y0, z0, x1, y1, z1} of the mesh's main mass: per axis the vertices within 2.5
-         * interquartile ranges of the middle half (Tukey fences); the full bounds when they are not much
+         * interquartile ranges of the middle half (Tukey fences), minus a smaller vertex group beyond a wide
+         * gap (a stray triangle on a low-poly model); the full bounds when they are not much
          * larger (far-off pieces such as a stray triangle or a huge ground plane would otherwise shrink the
          * model to a dot).
          */
@@ -473,6 +504,30 @@ final class MeshImportDialog extends JDialog {
                 while (v[hi] > q3 + fence) {
                     hi--;
                 }
+                // low-poly models: a stray piece can hold a quarter of the vertices and pass the fences –
+                // cut off the smaller side of a wide gap (fewer than half the vertices of the other side)
+                for (int pass = 0; pass < 8 && hi > lo; pass++) {
+                    int at = lo;
+                    for (int i = lo; i < hi; i++) {
+                        if (v[i + 1] - v[i] > v[at + 1] - v[at]) {
+                            at = i;
+                        }
+                    }
+                    double gap = v[at + 1] - v[at];
+                    int left = at - lo + 1, right = hi - at;
+                    double keep = left >= right ? v[at] - v[lo] : v[hi] - v[at + 1];
+                    if (gap <= 0.5 * (v[hi] - v[lo])
+                            || keep <= 0
+                            || gap <= 2 * keep
+                            || 2 * Math.min(left, right) > Math.max(left, right)) {
+                        break;
+                    }
+                    if (left >= right) {
+                        hi = at;
+                    } else {
+                        lo = at + 1;
+                    }
+                }
                 robust[axis] = v[lo];
                 robust[axis + 3] = v[hi];
                 far |= v[n - 1] - v[0] > 1.5 * (robust[axis + 3] - robust[axis]) + 1e-9;