autorig: gen-mesh mode — preclean (weld+degenerate+UV-preserving decimate to --tris budget) + manifold voxel-proxy bone-heat with weight transfer + smoothing passes

TRELLIS meshes never bone-heat directly (non-manifold even after weld); the watertight
proxy solves, POLYINTERP_NEAREST transfers (ACTIVE->SELECTED — reversed is a silent
no-op), 4x smooth knocks down shell-bleed spikes. Proven on the tradie: 194k->14k tris,
22 real groups, clean walk at game scale. --tris 0 = old direct path for authored meshes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bpy/autorig.py

@@ -249,12 +249,87 @@ def skin(meshes, arm_obj):
         rescue_unweighted(m, arm_obj)
 
 
+
+
+def proxy_skin(meshes, arm_obj):
+    """Bone-heat on a VOXEL-REMESHED manifold proxy, weights transferred back to the real textured
+    mesh (POLYINTERP_NEAREST). Gen meshes stay non-manifold even after preclean ("Mesh not valid"),
+    so direct bone heat can never solve them — the watertight proxy can, and the transfer keeps
+    UVs/materials untouched. Falls back to the old rescue if the proxy path itself fails."""
+    for m in meshes:
+        select_only([m], active=m)
+        bpy.ops.object.transform_apply(location=True, rotation=True, scale=True)
+        proxy = m.copy(); proxy.data = m.data.copy()
+        bpy.context.collection.objects.link(proxy)
+        try:
+            select_only([proxy], active=proxy)
+            rm = proxy.modifiers.new("mirpamo_vox", "REMESH")
+            rm.mode = "VOXEL"
+            dims = max(proxy.dimensions) or 1.0
+            rm.voxel_size = max(0.008, dims / 60.0)
+            bpy.ops.object.modifier_apply(modifier=rm.name)
+            select_only([proxy, arm_obj], active=arm_obj)
+            bpy.ops.object.parent_set(type="ARMATURE_AUTO")
+            groups = [g for g in proxy.vertex_groups]
+            if not groups:
+                raise RuntimeError("proxy solve produced no vertex groups")
+            # data_transfer flows ACTIVE -> SELECTED (bit us 2026-07-17: reversed = silent no-op)
+            select_only([m, proxy], active=proxy)
+            bpy.ops.object.data_transfer(use_create=True, data_type="VGROUP_WEIGHTS",
+                                         vert_mapping="POLYINTERP_NEAREST",
+                                         layers_select_src="ALL", layers_select_dst="NAME")
+            am = m.modifiers.new("Armature", "ARMATURE")
+            am.object = arm_obj
+            m.parent = arm_obj
+            rescue_unweighted(m, arm_obj)   # belt-and-braces for verts the transfer missed
+            # smooth the transferred weights — POLYINTERP bleed between close shells (vest/torso)
+            # shows as silhouette spikes; a few smoothing passes knock them down
+            select_only([m], active=m)
+            bpy.ops.object.mode_set(mode="WEIGHT_PAINT")
+            bpy.ops.object.vertex_group_smooth(group_select_mode="ALL", factor=0.5, repeat=4, expand=0.08)
+            bpy.ops.object.mode_set(mode="OBJECT")
+            print(f"[mirpamo] proxy-skin OK for {m.name} ({len(m.vertex_groups)} groups on the real mesh)")
+        except Exception as e:
+            print(f"[mirpamo] proxy-skin failed for {m.name} ({e}) — falling back to direct bone heat")
+            select_only([m, arm_obj], active=arm_obj)
+            bpy.ops.object.parent_set(type="ARMATURE_AUTO")
+            rescue_unweighted(m, arm_obj)
+        finally:
+            if proxy.name in bpy.data.objects:
+                bpy.data.objects.remove(proxy, do_unlink=True)
+
+
+def preclean(meshes, target_tris):
+    """Gen-mesh hygiene BEFORE landmarks/weights. TRELLIS/photogrammetry meshes arrive dense and
+    non-manifold: bone heat fails and the proximity fallback candy-wraps the joints (the tradie's
+    vest, 2026-07-17). Weld + degenerate-dissolve helps manifoldness; a UV-preserving collapse
+    decimate to the tri budget lightens the solve AND is the game's ped tri diet in the same pass.
+    target_tris=0 skips (authored meshes come in clean)."""
+    if not target_tris:
+        return
+    import bmesh
+    for m in meshes:
+        tris0 = sum(max(0, len(pg.vertices) - 2) for pg in m.data.polygons)
+        bm = bmesh.new(); bm.from_mesh(m.data)
+        bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=0.0005)
+        bmesh.ops.dissolve_degenerate(bm, edges=bm.edges, dist=0.0005)
+        bm.to_mesh(m.data); bm.free()
+        if tris0 > target_tris * 1.3:
+            mod = m.modifiers.new("mirpamo_decimate", "DECIMATE")
+            mod.ratio = max(0.02, target_tris / max(tris0, 1))
+            bpy.context.view_layer.objects.active = m
+            bpy.ops.object.modifier_apply(modifier=mod.name)
+        tris1 = sum(max(0, len(pg.vertices) - 2) for pg in m.data.polygons)
+        print(f"[mirpamo] preclean {m.name}: {tris0} -> {tris1} tris")
+
+
 def main():
     ap = argparse.ArgumentParser()
     ap.add_argument("--in", dest="inp", required=True)
     ap.add_argument("--out", required=True)
     ap.add_argument("--markers", default=None)
     ap.add_argument("--name", default=None)
+    ap.add_argument("--tris", type=int, default=16000)
     args = ap.parse_args(stage_args())
 
     overrides = {}
@@ -270,12 +345,16 @@ def main():
     if not meshes:
         die("input contains no mesh")
 
+    preclean(meshes, args.tris)
     verts = gather_world_verts(meshes)
     L = detect_landmarks(verts, overrides)
     print(f"[mirpamo] mesh height {L['_height']:.3f}m, "
           f"{len(verts)} verts, landmarks detected")
 
     arm_obj = build_skeleton(L, name)
+    if args.tris:
+        proxy_skin(meshes, arm_obj)   # gen-mesh mode: manifold proxy solve + weight transfer
+    else:
         skin(meshes, arm_obj)
 
     # sanity: every mesh must now have an armature modifier