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

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):