feat(camera): third-person rig, V toggle, visible body

One pawn, both rigs (ADR-9): a skeletal body hidden in first person, a
collision-tested spring arm, and a toggle that swaps the active camera and the
body's visibility. Shipped default stays first person; -thirdperson starts the
pawn in the third-person rig so the review shot is reproducible, and the
screenshot run passes it.

Three defects found and two fixed:
- The skin material had no SkeletalMesh usage flag, so Unreal silently substituted
  the default grey. That is why the body rendered as clay.
- render_screenshots.sh still called ./Engine/... on this branch (the fix lives on
  the facade branch and never reached main); applied here so the shots generate.
- OPEN: the idle clip is bound and PlayAnimation is called - the run logs the clip
  name - but the body still renders in bind pose, arms out. Recorded with that
  evidence in TODO.md rather than called done.

Shot 5 (demo-third-person) added and documented; camera collision is implemented
but unproven, since the spawn has open space behind it.

Tools/character_anim_build.py

@@ -55,6 +55,20 @@ ELBOW = 0.18
 
 PARTS: list[dict] = []
 
+# The .blend stores the raw A-pose bind: `mpfb_character_export.py --pose idle`
+# bakes the arms down only in the exported FBX, not in the file. A clip that
+# animates only swing therefore leaves the arms out in an A — which is exactly how
+# the first third-person render looked. These are the same deltas `IDLE_POSE` uses,
+# applied as a base that every key sits on top of.
+BASE = {
+    "shoulder01.L": (0.0, -0.15, -0.03),
+    "shoulder01.R": (0.0, 0.15, 0.03),
+    "upperarm01.L": (0.0, 0.0, -1.55),
+    "upperarm01.R": (0.0, 0.0, 1.55),
+    "lowerarm01.L": (0.0, 0.0, -0.10),
+    "lowerarm01.R": (0.0, 0.0, 0.10),
+}
+
 
 def log(msg):
     PARTS.append(msg)
@@ -78,7 +92,9 @@ def pose_bones(arm):
 
 
 def key_euler(pb, frame, x=0.0, y=0.0, z=0.0):
-    pb.rotation_euler = (x, y, z)
+    """Key a pose-bone rotation on top of the arms-down base."""
+    bx, by, bz = BASE.get(pb.name, (0.0, 0.0, 0.0))
+    pb.rotation_euler = (bx + x, by + y, bz + z)
     pb.keyframe_insert(data_path="rotation_euler", frame=frame)
 
 

Tools/render_screenshots.sh

@@ -39,8 +39,11 @@ run_cmdlet ue_build_review_map.py "5/6 stage the demo shot cameras"
 tail -3 /tmp/ue-review-map-result.txt 2>/dev/null || true
 
 echo "== 6/6 capture the demo map =="
-./Engine/Binaries/Linux/UnrealEditor-Cmd "$PROJ" /Game/Hollywood/DemoMap \
-  -game -windowed -ResX=1920 -ResY=1080 -nopause -nosplash -stdout
+# Absolute engine path: this step runs from the repo, not from $ENGINE, and a bare
+# ./Engine/... failed with "No such file or directory" while every commandlet above
+# succeeded through run_cmdlet's cd. -thirdperson so the review shows the body.
+"$ENGINE/Engine/Binaries/Linux/UnrealEditor-Cmd" "$PROJ" /Game/Hollywood/DemoMap \
+  -game -windowed -ResX=1920 -ResY=1080 -nopause -nosplash -thirdperson -stdout
 
 echo "== collect the demo screenshots =="
 mkdir -p "$REPO/Screenshots/demo"

Tools/ue_build_review_map.py

@@ -308,6 +308,11 @@ try:
             # (X -22750) and look NORTH toward the mass. The old camera was at
             # X -22800 Y +2600 aiming at its own X, giving an 85%-sky frame.
             ("demo-north-buildings", unreal.Vector(-22750, 1600, 500), unreal.Vector(-22750, -5200, 350)),
+            # 0.2.0 third-person body. Stands where the pawn's own boom camera sits —
+            # 3.4 m behind the spawn point, 1 m above it — and looks at the pawn, so
+            # the visible body and its idle clip are what the shot is for.
+            # Demo_PlayerStart is at (-13336, -1150, 600), yaw 90 (facing +Y).
+            ("demo-third-person", unreal.Vector(-13336, -1750, 780), unreal.Vector(-13336, -1150, 560), 58.0),
         ]
         seq = spawn(unreal.GigLineShotActor, unreal.Vector(0, 0, 300), "ShotSequencer")
         if seq:

Tools/ue_create_input_assets.py

@@ -127,6 +127,10 @@ def build():
     ia_reset.set_editor_property("value_type", unreal.InputActionValueType.BOOLEAN)
     save(ia_reset)
 
+    ia_cam = fresh("IA_ToggleCamera", unreal.InputAction, unreal.InputAction_Factory)
+    ia_cam.set_editor_property("value_type", unreal.InputActionValueType.BOOLEAN)
+    save(ia_cam)
+
     ia_pause = fresh("IA_Pause", unreal.InputAction, unreal.InputAction_Factory)
     ia_pause.set_editor_property("value_type", unreal.InputActionValueType.BOOLEAN)
     save(ia_pause)
@@ -136,7 +140,7 @@ def build():
         (ia_move, "Gamepad_LeftY"), (ia_strafe, "Gamepad_LeftX"),
         (ia_look, "MouseX"), (ia_look, "MouseY"), (ia_look, "Gamepad_Right2D"),
         (ia_jump, "SpaceBar"), (ia_jump, "Gamepad_FaceButton_Bottom"),
-        (ia_reset, "R"), (ia_pause, "Escape"),
+        (ia_reset, "R"), (ia_pause, "Escape"), (ia_cam, "V"),
     ]
 
     mappings = []

Tools/visual_targets.json

@@ -48,6 +48,18 @@
         "Art/reference/north-chinese/01-grauman-s-chinese-theatre-by-carol-highsmith.jpg"
       ],
       "expect": "The two north-side buildings (TCL Chinese Theatre, Madame Tussaud's) seen from across Hollywood Boulevard, full height in frame, daylight"
+    },
+    {
+      "name": "demo-third-person",
+      "shot": "Screenshots/demo/review-demo-third-person.png",
+      "size": [
+        1920,
+        1080
+      ],
+      "references": [
+        "Art/reference/hollywood/el-capitan-facade-day-wikimedia-2009-10-27.jpg"
+      ],
+      "expect": "Third-person view of the player body standing on the north sidewalk, full figure visible from behind, the hero facade across the street, daylight"
     }
   ]
 }