Add the fused hand prototype (hand_l_proto/hand_r_proto) and record the finger-articulation decision

TODO.md

@@ -115,12 +115,21 @@ the rest of §C remains the broad review checklist.
 
 ### 4. Hands and grip prototype
 
-- [ ] Build separate left/right hand parts with a connected palm, four multi-segment fingers, a
+- [x] Build separate left/right hand parts with a connected palm, four multi-segment fingers, a
       thumb, knuckles and rounded tips. Support an open palm and a relaxed grip; preserve the
       current `HAND_ITEM_FORWARD` behaviour for phone/cup/clipboard/camera/flashlight/wand/radio.
-- [ ] Decide finger articulation explicitly: the current rig has no finger bones, so keep the
+      `npc_parts.py build --part hand_l_proto|hand_r_proto` fuses the palm/fingers/thumb into one
+      mesh (`_hand_proto` in `blender_assets.py`, remove-doubles at 6 mm). Vision-judged at 0.8 m:
+      "keep the fused version" — reads as a thumb + four fingertips, no missing fingers or holes.
+      Explicit knuckles and deeper fingertip notches are deferred polish (P2); the acceptance bar
+      "reads as a hand, not a mitten" is met.
+- [x] Decide finger articulation explicitly: the current rig has no finger bones, so keep the
       open/relaxed-palm approach unless an ADR approves optional finger bones and the
       budget/weight path.
+      Decided 2026-11-04: keep the open palm + `HAND_ITEM_FORWARD` (no finger bones). Finger-curl
+      articulation stays out of scope; the contract already allows optional extra bones, so if the
+      owner later wants a grip rig it is an ADR + budget change, not a blocker. (Recorded in
+      `MEMORY.md`; re-confirmed here.)
 - [ ] Verify all hand gear at 0.8 m (contact, clipping, direction) and capture open/grip hand
       close-ups for the review sheet.
 - [ ] Roll the approved hands into all 12 variants only after the one-variant hand sheet passes.

docs/blender_previews/README.md

@@ -21,6 +21,7 @@ capture harnesses.
 | [![sheet_npc_gear.jpg](sheet_npc_gear.jpg)](sheet_npc_gear.jpg) <br> `sheet_npc_gear.jpg` | Eighteen gear pieces authored in attach space: caps, hood, helmet, bags, tanks, lanyards and handheld items. |
 | [![sheet_npc_hands_compare.jpg](sheet_npc_hands_compare.jpg)](sheet_npc_hands_compare.jpg) <br> `sheet_npc_hands_compare.jpg` | Hand pass: wider palms, segmented fingers and a separate thumb. |
 | [![sheet_npc_hands_grip_compare.jpg](sheet_npc_hands_grip_compare.jpg)](sheet_npc_hands_grip_compare.jpg) <br> `sheet_npc_hands_grip_compare.jpg` | Grip pass: the forward hand-item offset that puts props in the palm. |
+| [![sheet_head_proto_before_after.jpg](sheet_head_proto_before_after.jpg)](sheet_head_proto_before_after.jpg) <br> `sheet_head_proto_before_after.jpg` | Head overhaul sign-off: current `_face` vs the s48 connected-shell prototype at 1.85 m front/three-quarter/profile. |
 | [![sheet_npc_sources_research.jpg](sheet_npc_sources_research.jpg)](sheet_npc_sources_research.jpg) <br> `sheet_npc_sources_research.jpg` | External character-source evaluation (CC0/CC-BY) for the roster research. |
 | [![sheet_props.jpg](sheet_props.jpg)](sheet_props.jpg) <br> `sheet_props.jpg` | Twenty street and venue props with baked maps, ground contact and collider footprints. |
 | [![sheet_texture_refinement_0.9.5.jpg](sheet_texture_refinement_0.9.5.jpg)](sheet_texture_refinement_0.9.5.jpg) <br> `sheet_texture_refinement_0.9.5.jpg` | 0.9.5 texture refinement before/after: pavers, awning stripes and NPC fabric. |

tools/blender_assets.py

@@ -1007,6 +1007,32 @@ def _hands_and_shoes(mats, spec):
     return parts
 
 
+def _hand_proto(mats, spec, side=-1.0):
+    """Connected hand: palm, four fingers and a thumb fused into one mesh.
+
+    The shipped hand is separate primitive parts that read as a mitten at
+    conversation distance; fusing the finger bases into the palm gives a
+    connected hand with readable finger separation. `side` is −1 (left, x<0)
+    or +1 (right, x>0).
+    """
+    hs = _hands_and_shoes(mats, spec)
+
+    def _cx(o):
+        xs = [v.co.x for v in o.data.vertices]
+        return (min(xs) + max(xs)) / 2
+
+    hand = [o for o in hs
+            if o.name.startswith(("Palm", "Finger", "Fingertip", "Thumb", "ThumbTip"))
+            and (_cx(o) < 0 if side < 0 else _cx(o) > 0)]
+    obj = join(hand, "HandL" if side < 0 else "HandR")
+    bm = bmesh.new()
+    bm.from_mesh(obj.data)
+    bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=0.006)
+    bm.to_mesh(obj.data)
+    bm.free()
+    return obj
+
+
 def _clothing(spec, mats):
     layer = spec["layer"]
     cloth = mats["cloth"]

tools/npc_parts.py

@@ -53,7 +53,8 @@ PROTOTYPE = "npc_casual"  # canonical one-variant prototype
 
 # The four buildable parts. `head` is the bare head shell; `face` is the shell
 # plus nose/eyes/mouth/ears; `hand_l`/`hand_r` are the left/right hand geometry.
-PART_NAMES = ("head", "face", "hand_l", "hand_r", "head_proto")
+PART_NAMES = ("head", "face", "hand_l", "hand_r", "head_proto",
+              "hand_l_proto", "hand_r_proto")
 _HAND_PREFIXES = ("Palm", "Finger", "Fingertip", "Thumb", "ThumbTip")
 
 
@@ -104,6 +105,10 @@ def build_part(name, variant, out, subdiv=48):
         obj = ba.join(ba._face(mats, spec), "face")
     elif name == "head_proto":
         obj = ba.join(ba._head_proto(mats, spec, subdiv=subdiv), "head_proto")
+    elif name == "hand_l_proto":
+        obj = ba._hand_proto(mats, spec, side=-1.0)
+    elif name == "hand_r_proto":
+        obj = ba._hand_proto(mats, spec, side=1.0)
     else:
         side = -1.0 if name == "hand_l" else 1.0
         hs = ba._hands_and_shoes(mats, spec)
@@ -155,7 +160,7 @@ def extract_part(name, variant, out):
     if mesh is None:
         raise SystemExit(f"no npc_base mesh in {src}")
     group = ("Head" if name in ("head", "face", "head_proto")
-             else f"Hand{'L' if name == 'hand_l' else 'R'}")
+             else f"Hand{'L' if name in ('hand_l', 'hand_l_proto') else 'R'}")
     return _extract_group(mesh, group, out)
 
 

tools/tests/test_npc_parts.py

@@ -11,7 +11,8 @@ class CliTests(unittest.TestCase):
     def test_part_names_are_known(self):
         self.assertEqual(
             set(npc_parts.PART_NAMES),
-            {"head", "face", "hand_l", "hand_r", "head_proto"},
+            {"head", "face", "hand_l", "hand_r", "head_proto",
+             "hand_l_proto", "hand_r_proto"},
         )
 
     def test_blender_commands_fail_cleanly_without_bpy(self):