fix(hero): export smoothing groups; give the facade real collision

UE export hygiene (unreal-export skill checklist) plus a gameplay defect the new
probe caught:

- FBX export now uses mesh_smooth_type="FACE" (was OFF, which is why every import
  logged "No smoothing group information was found"), and the round parts are
  shaded with shade_smooth_by_angle(35 deg) before export, so columns and
  medallions read round instead of faceted.
- SM_HeroFacade had complex-only collision, so capsule sweeps and line traces
  passed through the wall: the player could walk through the hero facade.
  auto_generate_collision was tried and rejected (coarse hulls bulged into the
  street; the QA wall probe went 0/35 -> 2/35). It now uses UseComplexAsSimple,
  saved on the asset, like the terrain.
- New -qaselftest facade occlusion probe: 40 m traces sideways from the road
  centre at walking height, required only where a building is staged (explicit X
  spans mirroring ue_build_demo_map). Result 0/9 -> PASS, alongside transect
  0 holes and wall probe 0/35.

Docs: release-checks records the probe and both collision attempts; Tools/README
lists the new phase; MEMORY records the smoothing/collision lessons.

Docs/release-checks.md

@@ -95,6 +95,15 @@ Run on the packaged build (`GigLineQA`, Development, Vulkan SM5) with `-qaselfte
 - **Invisible-wall probe:** horizontal traces 30 m long, grounded at 160 cm above
   the local ground, along the road and both seam rows. Result **0/35 blocking hits
   inside 21 m** — no invisible walls or misplaced blockers in the street envelope.
+- **Facade occlusion probe:** from the road centre, 40 m traces sideways at walking
+  height toward each frontage, required only where the map stages a building (the
+  spans are listed in `AGigLineCharacter` and mirror `Tools/ue_build_demo_map.py`).
+  Result **0/9 directions without a blocking wall** — the player cannot walk
+  through the hero or the frontage. This probe found the hero façade had **no
+  simple collision** at all (complex-only, so traces and capsule sweeps passed
+  through it); it is now `UseComplexAsSimple`. Auto-generated convex hulls were
+  tried first and rejected: on a 95-part, 26 m façade they bulged into the street
+  (the wall probe went 0/35 → 2/35).
   (First pass used a fixed Z 160 start; the street is at Z ~366, so the probe
   started inside the earth and reported every row as a dist-0 blocker. Grounding
   the probe fixed that measurement bug.)

Game/GigLine/Source/GigLine/GigLineCharacter.cpp

@@ -416,6 +416,81 @@ void AGigLineCharacter::StartQASelfTest()
 					TEXT("GigLine QA: wall probe %d/%d traces with blocking hit inside 21 m -> %s"),
 					Walls, WallSamples,
 					Walls == 0 ? TEXT("PASS") : TEXT("FAIL"));
+
+				// Facade occlusion probe: walkable street is only half the story —
+				// the player must also NOT be able to walk through the buildings.
+				// From the road centre, fire 40 m sideways at walking height toward
+				// each frontage and require a blocking hit. A miss means the
+				// building has no collision (or only non-blocking collision) and the
+				// player would pass through the wall.
+				// Expect a wall only where the map actually stages a building.
+				// Spans below mirror the actors placed by Tools/ue_build_demo_map.py
+				// (frontage + hero) and the two north buildings; update them if
+				// that list changes. Gaps between buildings are legitimate misses.
+				struct FSpan { float Min, Max; };
+				static const FSpan SouthSpans[] = {
+					{-24276.f, -17700.f}, // 6922
+					{-17749.f, -14591.f}, // 6902
+					{-14638.f, -12034.f}, // 6840 hero
+					{-12082.f, -8210.f},  // 6838 El Capitan Theatre
+					{-7854.f, -7252.f},   // 6822 Budget
+					{-6608.f, -3307.f},   // 6806-6820
+					{-3320.f, -1437.f},   // 6800 Lee Drug
+				};
+				static const FSpan NorthSpans[] = {
+					{-27071.f, -22799.f}, // Madame Tussaud's
+					{-22889.f, -18442.f}, // TCL Chinese Theatre
+				};
+				auto InSpans = [](const FSpan* Spans, int32 Count, float X)
+				{
+					for (int32 i = 0; i < Count; ++i)
+					{
+						if (X >= Spans[i].Min && X <= Spans[i].Max) { return true; }
+					}
+					return false;
+				};
+				int32 Facades = 0, FacadeSamples = 0;
+				for (float X0 = -19000.0f; X0 <= -3000.0f; X0 += 2000.0f)
+				{
+					for (float Dir : {1.0f, -1.0f}) // +Y south frontage, -Y north side
+					{
+						const bool bExpectWall = (Dir > 0.0f)
+							? InSpans(SouthSpans, UE_ARRAY_COUNT(SouthSpans), X0)
+							: InSpans(NorthSpans, UE_ARRAY_COUNT(NorthSpans), X0);
+						if (!bExpectWall)
+						{
+							continue;
+						}
+						FHitResult GroundHit2;
+						FCollisionQueryParams GQ2(TEXT("GigLineFacadeGround"), false, this);
+						if (!W->LineTraceSingleByChannel(GroundHit2,
+							FVector(X0, 0.0f, 3000.f), FVector(X0, 0.0f, -1000.f),
+							ECC_Visibility, GQ2))
+						{
+							continue;
+						}
+						const float ProbeZ2 = GroundHit2.ImpactPoint.Z + 160.f;
+						FHitResult Hit2;
+						FCollisionQueryParams Q2(TEXT("GigLineFacadeProbe"), false, this);
+						const bool bHit2 = W->LineTraceSingleByChannel(Hit2,
+							FVector(X0, 0.0f, ProbeZ2),
+							FVector(X0, Dir * 4000.f, ProbeZ2),
+							ECC_Visibility, Q2);
+						++FacadeSamples;
+						const bool bBlocking = bHit2 && Hit2.GetActor() != nullptr;
+						if (!bBlocking)
+						{
+							++Facades;
+							UE_LOG(LogTemp, Log,
+								TEXT("GigLine QA: facade probe miss at X %.0f dir %.0f (no blocking hit in 40 m)"),
+								X0, Dir);
+						}
+					}
+				}
+				UE_LOG(LogTemp, Log,
+					TEXT("GigLine QA: facade probe %d/%d directions without a blocking wall -> %s"),
+					Facades, FacadeSamples,
+					Facades == 0 ? TEXT("PASS") : TEXT("FAIL"));
 			}
 
 			// 7.0: verdict, then stop ticking.

MEMORY.md

@@ -440,3 +440,23 @@ Scope: facts and traps that cost time to establish. Planned work lives in [TODO.
   `review-hero-facade-front`.
 - Reminder: `.blend` is LFS read-only on checkout — `chmod u+w` or Blender fails
   with "Cannot save blend file … not writable" (this bit again here).
+
+## 2026-11-09 — UE export hygiene: smoothing groups + facade collision
+
+- **All our FBX exporters used `mesh_smooth_type="OFF"`**, which is why every Unreal
+  import logged "No smoothing group information was found for this mesh". The hero
+  now exports `"FACE"` and its round parts are shaded with
+  `shade_smooth_by_angle(35°)` before export: cylinders read as round instead of
+  faceted, and the import warning is gone (6 → 0).
+- **The hero façade had no simple collision** (complex-only), so line traces and
+  capsule sweeps passed straight through it — the player could walk through the
+  wall of the demo. Caught by a new `-qaselftest` **facade occlusion probe** (40 m
+  sideways traces from the road centre at walking height).
+- **Auto-generated convex collision on a 95-part 26 m façade is unusable**: it
+  produced coarse hulls that bulged into the street and the wall probe went
+  0/35 → 2/35. Rejected in favour of `UseComplexAsSimple` via
+  `UGigLineAssetTools.set_complex_collision_as_simple` (same reason the terrain
+  uses it), saved on the asset.
+- Probe expectations must mirror the staged buildings: the facade probe now carries
+  explicit X spans per frontage (and the TCL/Tussaud's spans on the north side) so
+  a gap between buildings is not reported as a defect.

Tools/README.md

@@ -57,7 +57,7 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 | Command | Purpose |
 | --- | --- |
 | `UnrealEditor <uproject> /Game/Hollywood/DemoMap -game -qaselftest` | Headless behaviour check: drives forward input for 2 s, then resets and pauses. Logs `GigLine QA: ... PASS/FAIL` lines and a final `RESULT`. Runs only with `-qaselftest`, so normal play is unaffected. |
-| `-qaselftest` phases | Walk, reset, pause/unpause, a 16-row seam transect (0 holes) and a ground-referenced wall probe (0/35), plus a frame-time capture writing `Saved/Profiling/perf-walk-frametimes.csv` and logging `GigLine PERF:`. |
+| `-qaselftest` phases | Walk, reset, pause/unpause, a 16-row seam transect (0 holes), a ground-referenced wall probe (0/35) and a **facade occlusion probe** that fires sideways from the road centre and requires a blocking wall wherever a building is staged (0/9), plus a frame-time capture writing `Saved/Profiling/perf-walk-frametimes.csv` and logging `GigLine PERF:`. |
 | `gigline.SetupLogs` cvar | Spawn/input setup logging, **off by default** (`DefaultEngine.ini [ConsoleVariables]`); enable at runtime with `gigline.SetupLogs 1`. |
 
 ## Reference and concept generation

Tools/hero_facade_build.py

@@ -74,7 +74,7 @@ def cube(name, x, y, z, dx, dy, dz, material=None):
     return obj
 
 
-def cylinder(name, x, y, z0, z1, radius, material, vertices=24):
+def cylinder(name, x, y, z0, z1, radius, material, vertices=24, smooth=True):
     bpy.ops.mesh.primitive_cylinder_add(
         vertices=vertices,
         radius=radius,
@@ -85,6 +85,11 @@ def cylinder(name, x, y, z0, z1, radius, material, vertices=24):
     obj.name = name
     if material:
         obj.data.materials.append(material)
+    if smooth:
+        # Round parts must shade smoothly *around* the axis while keeping the
+        # caps creased. Without this the columns read as faceted prisms, and the
+        # FBX carries no smoothing groups at all (Unreal warns about it).
+        bpy.ops.object.shade_smooth_by_angle(angle=math.radians(35.0))
     return obj
 
 
@@ -313,7 +318,9 @@ def export_fbx(path):
         axis_up="Z",
         use_space_transform=True,
         use_mesh_modifiers=True,
-        mesh_smooth_type="OFF",
+        # "FACE" exports smoothing groups; without it every import logs
+        # "No smoothing group information was found for this mesh".
+        mesh_smooth_type="FACE",
         path_mode="AUTO",
         bake_space_transform=False,
     )

Tools/ue_hero_facade_import.py

@@ -61,6 +61,16 @@ def measure_and_place():
     if asset is None:
         log(f"MISSING {DEST}/SM_HeroFacade")
         return
+    # Collision: complex-as-simple, not auto-generated convex hulls.
+    # The facade is 95 separate parts across 26 m; Unreal's auto hull generation
+    # wraps them in a few coarse hulls that bulged into the street (the QA wall
+    # probe went 0/35 -> 2/35 after trying it). Complex-as-simple makes the real
+    # triangles the simple collision, so line traces and capsule sweeps block on
+    # the actual wall — the same approach used for the terrain, for the same
+    # reason. The flag lives on the asset, so save it explicitly.
+    unreal.GigLineAssetTools.set_complex_collision_as_simple(asset, True)
+    saved = unreal.EditorAssetLibrary.save_loaded_asset(asset)
+    log(f"collision: {unreal.GigLineAssetTools.get_collision_complexity(asset)} (saved={saved})")
     box = asset.get_bounding_box()
     mn, mx = box.min, box.max
     log(f"SM_HeroFacade bounds cm: size=({mx.x - mn.x:.1f}, {mx.y - mn.y:.1f}, {mx.z - mn.z:.1f}) "