backend/engine/cdsl_engine/capabilities.py

@@ -18,6 +18,9 @@ from .operation_contracts import materialized_feature_contracts
 
 _SELECTOR_REQUIRED = frozenset({"fillet", "chamfer"})
 _SKETCH_ATOM_PREFIXES = ("extrude_", "revolve_")
+# 开放轮廓（closed=false / role=open）只有"刀具截面补槽口边闭合后作切除"的
+# 物理意义：仅 extrude 直切类原子支持；add/回转对开放轮廓会造出无意义的封块。
+_OPEN_PROFILE_ATOMICS = frozenset({"extrude_cut_blind", "extrude_cut_through"})
 _PRIMARY_ATOMICS = frozenset({
     "extrude_add_blind", "extrude_add_two_sided", "extrude_cut_blind",
     "extrude_cut_through",
@@ -281,6 +284,17 @@ class CapabilityAnalyzer:
                                 "The resolved sketch contains no closed profile region",
                                 sketch_id=node.sketch_id,
                             ))
+                        elif (
+                            not resolution_error
+                            and sketches[node.sketch_id].get("_open_contour")
+                            and node.atomic_id not in _OPEN_PROFILE_ATOMICS
+                        ):
+                            blockers.append(self._blocker(
+                                node.feature_id, "unsupported_open_profile",
+                                "Open profiles are only supported for straight extruded cut features",
+                                sketch_id=node.sketch_id,
+                                atomic_id=node.atomic_id,
+                            ))
             if node.atomic_id.startswith(_SKETCH_ATOM_PREFIXES):
                 # #2 draft：extrudeParams.draft 在 cdsl_schema.json 中被允许，
                 # 但 runtime 的拉伸执行器（build123d Solid.extrude）没有锥形

backend/engine/cdsl_engine/sketch_solver.py

@@ -121,7 +121,9 @@ def _reverse(edge: _Ctx) -> _Ctx:
     return output
 
 
-def _join(edges: list[_Ctx]) -> list[_Ctx]:
+def _join(edges: list[_Ctx], *, allow_open: bool = False) -> list[_Ctx]:
+    # 将边排序成一条连通链。allow_open=False（默认）要求首尾相接成闭合环；
+    # allow_open=True 时允许链首尾不接（供开放轮廓先拼链、后补闭合边）。
     if not edges:
         return []
     remaining = [deepcopy(edge) for edge in edges]
@@ -137,11 +139,22 @@ def _join(edges: list[_Ctx]) -> list[_Ctx]:
                 break
         else:
             raise ValueError("analytic_contours: segments do not form a connected contour")
-    if _distance(ordered[0]["start_mm"], ordered[-1]["end_mm"]) > _TOLERANCE_MM:
+    if not allow_open and _distance(ordered[0]["start_mm"], ordered[-1]["end_mm"]) > _TOLERANCE_MM:
         raise ValueError("analytic_contours: closed contour endpoints do not meet")
     return ordered
 
 
+def _close_open_contour(edges: list[_Ctx]) -> tuple[list[_Ctx], bool]:
+    # 开放链补闭合边：若首尾未相接，则沿两点连线补一条直线边形成闭合环。
+    # 返回 (edges, opened)；opened=False 表示首尾已天然相接（无需补边）。
+    if len(edges) < 2:
+        raise ValueError("analytic_contours: open contour needs at least 2 connected segments")
+    if _distance(edges[0]["start_mm"], edges[-1]["end_mm"]) <= _TOLERANCE_MM:
+        return edges, False
+    closing = _contour_line(edges[-1]["end_mm"][:2], edges[0]["start_mm"][:2])
+    return [*edges, closing], True
+
+
 def _circle_edges(segment: _Ctx) -> list[_Ctx]:
     center = segment.get("center") or [0.0, 0.0]
     radius = float(segment.get("radius_mm") or 0.0)
@@ -239,22 +252,35 @@ def _gen_analytic_contours(profile: _Ctx, meta: _Ctx) -> tuple[list[_Ctx], list[
     loops: list[_Ctx] = []
     entities: list[_Ctx] = []
     for index, contour in enumerate(profile.get("contours") or []):
-        if not contour.get("closed"):
-            raise ValueError(f"analytic_contours: contour {index} is open")
+        # 开放轮廓（closed=false / role=open）：先按开放链拼装，再在首尾间补一条
+        # 闭合边成闭合 region —— V 槽/开放型腔切除的刀具截面本就靠这条"槽口边"
+        # 闭合，故 B-rep 层可完全复用闭合链路。
+        contour_open = not bool(contour.get("closed", False))
+        if contour_open and contour.get("role") == "inner":
+            raise ValueError(f"analytic_contours: inner contour {index} cannot be open")
         raw_edges: list[_Ctx] = []
         for segment in contour.get("segments") or []:
             if segment.get("type") == "line":
                 entities.append(_line(segment["start"], segment["end"]))
             elif segment.get("type") == "circle":
+                if contour_open:
+                    raise ValueError(f"analytic_contours: open contour {index} cannot contain a full circle segment")
                 entities.append(_circle(segment.get("center") or [0.0, 0.0], float(segment.get("radius_mm") or 0.0)))
             raw_edges.extend(_segment_edges(segment))
         if raw_edges:
-            edges = _join(raw_edges)
+            edges = _join(raw_edges, allow_open=contour_open)
+            contour_opened = False
+            if contour_open:
+                if _distance(edges[0]["start_mm"], edges[-1]["end_mm"]) <= _TOLERANCE_MM:
+                    raise ValueError(f"analytic_contours: contour {index} is geometrically closed; use closed=true")
+                edges, contour_opened = _close_open_contour(edges)
+                meta["_has_open_contour"] = True
             _normalize_quarter_rounding_direction(edges)
             sample = _sample_loop(edges)
             if _area(sample) <= _TOLERANCE_MM * _TOLERANCE_MM:
                 raise ValueError(f"analytic_contours: contour {index} is degenerate")
-            loops.append({"edges": edges, "points": sample, "area": _area(sample)})
+            loops.append({"edges": edges, "points": sample, "area": _area(sample),
+                          "open": contour_open and contour_opened})
     for segment in profile.get("construction") or []:
         if segment.get("type") == "line":
             entities.append(_line(segment["start"], segment["end"], construction=True))
@@ -265,11 +291,13 @@ def _gen_analytic_contours(profile: _Ctx, meta: _Ctx) -> tuple[list[_Ctx], list[
     for loop in loops:
         loop["role"] = "inner" if sum(_contains(loop["points"][0], other["points"]) for other in loops if other is not loop) % 2 else "outer"
     outers = [loop for loop in loops if loop["role"] == "outer"]
-    regions = [{"outer": outer["edges"], "holes": []} for outer in outers]
+    regions = [{"outer": outer["edges"], "holes": [], "open": bool(outer.get("open"))} for outer in outers]
     for inner in (loop for loop in loops if loop["role"] == "inner"):
         containing = [outer for outer in outers if _contains(inner["points"][0], outer["points"])]
         if not containing:
             raise ValueError("analytic_contours: inner contour has no containing outer contour")
+        if any(outer.get("open") for outer in containing):
+            raise ValueError("analytic_contours: an open outer contour cannot contain nested holes")
         selected = min(containing, key=lambda outer: outer["area"])
         regions[outers.index(selected)]["holes"].append(inner["edges"])
     meta["_regions"] = regions
@@ -300,7 +328,7 @@ def resolve_profile(sketch: _Ctx) -> _Ctx:
     generator = SHAPE_GENERATORS.get(profile.get("type"))
     if generator is None:
         raise ValueError(f"sketch {sketch.get('id')}: unsupported profile type {profile.get('type')!r}")
-    meta: _Ctx = {"id": sketch.get("id"), "_entities": sketch.get("entities"), "_regions": []}
+    meta: _Ctx = {"id": sketch.get("id"), "_entities": sketch.get("entities"), "_regions": [], "_has_open_contour": False}
     entities, contour = generator(profile, meta)
     output = deepcopy(sketch)
     original_circles = [entity for entity in sketch.get("entities") or [] if entity.get("type") == "circle" and not entity.get("construction")]
@@ -310,9 +338,13 @@ def resolve_profile(sketch: _Ctx) -> _Ctx:
         output["contour_edges_mm"] = _transform_contours(contour, workplane) if workplane else contour
     if meta["_regions"]:
         output["contour_regions_mm"] = [
-            {"outer": _transform_contours(region["outer"], workplane) if workplane else region["outer"], "holes": [_transform_contours(hole, workplane) if workplane else hole for hole in region.get("holes") or []]}
+            {"outer": _transform_contours(region["outer"], workplane) if workplane else region["outer"],
+             "holes": [_transform_contours(hole, workplane) if workplane else hole for hole in region.get("holes") or []],
+             "open": bool(region.get("open"))}
             for region in meta["_regions"]
         ]
+    if meta["_has_open_contour"]:
+        output["_open_contour"] = True
     return output