Route with copper zones, and let vias into no-tracks areas

freeroute ignored the DSN's planes (KiCad's zones), so it never knew that
pads in a pour are joined by it. On the rc4 power stage those pads sit
inside "keep router off" areas as well, and every connection to them was
dropped without a word.

- Read (plane <net> <shape>) and put each zone on the board as a
  ConductionArea of its net. Zones are not obstacles: KiCad refills them
  around other nets' copper.
- The grid groups each net's pads and zone pieces that copper already
  joins (a pad in a zone, two zones sharing a pad) and routes only between
  groups. A connection may end on a zone by a via inside its copper, or by
  a track where tracks are allowed.
- wire_keepout now blocks traces only, as KiCad's "no tracks" rule area
  does; via_keepout only vias; keepout both, in the grid and in the exact
  verifier.

rc4 power stage, exact engine, resolution 2: 2 unconnected, down from 8
(FreeRouting JAR: 12), no DRC errors.

src/freeroute/board/board.py

@@ -12,7 +12,7 @@ from __future__ import annotations
 from freeroute.geometry import IntBox
 
 from .clearance import ClearanceMatrix
-from .items import Item, ObstacleArea, Pin, Trace, Via
+from .items import ConductionArea, Item, ObstacleArea, Pin, Trace, Via
 from .layer import LayerStructure
 from .net import Nets
 
@@ -57,7 +57,15 @@ class BasicBoard:
         return [it for it in self._items if isinstance(it, Pin)]
 
     def get_obstacle_areas(self) -> list[ObstacleArea]:
-        return [it for it in self._items if isinstance(it, ObstacleArea)]
+        """Keepouts. Copper zones are not obstacles; see get_conduction_areas."""
+        return [
+            it
+            for it in self._items
+            if isinstance(it, ObstacleArea) and not isinstance(it, ConductionArea)
+        ]
+
+    def get_conduction_areas(self) -> list[ConductionArea]:
+        return [it for it in self._items if isinstance(it, ConductionArea)]
 
     def get_traces(self) -> list[Trace]:
         return [it for it in self._items if isinstance(it, Trace)]

src/freeroute/board/build.py

@@ -31,7 +31,7 @@ from freeroute.geometry.polygon_shape import PolygonShape
 
 from .board import BasicBoard
 from .clearance import ClearanceMatrix
-from .items import ObstacleArea, Pin
+from .items import ConductionArea, ObstacleArea, Pin
 from .layer import Layer, LayerStructure
 from .net import Nets
 from .transform import CoordinateTransform
@@ -55,6 +55,7 @@ def build_board(dsn: DsnBoard) -> BasicBoard:
     _insert_pins(dsn, board, transform, terminal_to_net)
     _insert_keepouts(dsn, board, transform)
     _insert_image_keepouts(dsn, board, transform)
+    _insert_zones(dsn, board, transform, nets)
     return board
 
 
@@ -330,6 +331,8 @@ def _insert_keepouts(dsn: DsnBoard, board: BasicBoard, transform: CoordinateTran
                     name=keepout.area.name,
                     layer=layer_index,
                     tiles=tiles,
+                    blocks_wires=keepout.kind != "via_keepout",
+                    blocks_vias=keepout.kind != "wire_keepout",
                 )
             )
 
@@ -402,13 +405,17 @@ def _insert_image_keepouts(dsn: DsnBoard, board: BasicBoard, transform: Coordina
         image = images.get(placement.lib_name)
         if image is None:
             continue
-        areas = [*image.keepouts, *image.via_keepouts, *image.wire_keepouts]
+        areas = [
+            *((a, True, True) for a in image.keepouts),
+            *((a, False, True) for a in image.via_keepouts),
+            *((a, True, False) for a in image.wire_keepouts),
+        ]
         if not areas:
             continue
         for place in placement.places:
             if place.x is None or place.y is None:
                 continue
-            for area in areas:
+            for area, blocks_wires, blocks_vias in areas:
                 border = area.border
                 if border is None:
                     continue
@@ -423,7 +430,12 @@ def _insert_image_keepouts(dsn: DsnBoard, board: BasicBoard, transform: Coordina
                     top, bottom = min(signal_layers), max(signal_layers)
                     layers = [top + bottom - layer for layer in layers]
                 for layer_index in layers:
-                    board.insert(ObstacleArea(name=area.name, layer=layer_index, tiles=tiles))
+                    board.insert(
+                        ObstacleArea(
+                            name=area.name, layer=layer_index, tiles=tiles,
+                            blocks_wires=blocks_wires, blocks_vias=blocks_vias,
+                        )
+                    )
 
 
 def _placed_area_tiles(shape: Shape, place, transform: CoordinateTransform) -> list:
@@ -447,3 +459,29 @@ def _placed_area_tiles(shape: Shape, place, transform: CoordinateTransform) -> l
     if len(pts) < 3:
         return []
     return [tile for tile in PolygonShape(pts).split_to_convex() if not tile.is_empty()]
+
+
+def _insert_zones(dsn: DsnBoard, board: BasicBoard, transform: CoordinateTransform, nets) -> None:
+    """Each DSN plane as a ConductionArea of its net on its layer."""
+    layer_no = {layer.name: i for i, layer in enumerate(dsn.layers)}
+    numbers = {net.name: net.net_number for net in nets}
+    for plane in dsn.planes:
+        shape = plane.shape
+        if plane.net not in numbers or shape.layer not in layer_no:
+            continue
+        if not isinstance(shape, (Polygon, Path)):
+            continue
+        c = shape.coords
+        pts = [transform.dsn_to_board_point(c[i], c[i + 1]) for i in range(0, len(c) - 1, 2)]
+        if len(pts) < 3:
+            continue
+        polygon = PolygonShape(pts)
+        tiles = [t for t in polygon.split_to_convex() if not t.is_empty()]
+        if not tiles:
+            continue
+        board.insert(
+            ConductionArea(
+                net_nos=[numbers[plane.net]], name=plane.net, layer=layer_no[shape.layer],
+                tiles=tiles, polygon=polygon, blocks_wires=False, blocks_vias=False,
+            )
+        )

src/freeroute/board/items.py

@@ -72,6 +72,10 @@ class ObstacleArea(Item):
     name: str | None = None
     layer: int = 0
     tiles: list = field(default_factory=list)
+    #: a DSN keepout blocks both; wire_keepout only traces (KiCad's "no
+    #: tracks" rule area, where vias are allowed), via_keepout only vias
+    blocks_wires: bool = True
+    blocks_vias: bool = True
 
     def is_obstacle(self) -> bool:
         return True
@@ -87,7 +91,16 @@ class ObstacleArea(Item):
 
 @dataclass
 class ConductionArea(ObstacleArea):
-    """A power-plane conduction area (an obstacle carrying a net)."""
+    """A copper zone of one net (a DSN plane): not an obstacle to routing,
+    since KiCad refills it around other nets' copper, but copper of its net:
+    pads it touches are connected through it, and a route of its net ends on
+    it by placing a via inside it."""
+
+    #: the zone outline, for point containment
+    polygon: object = None
+
+    def is_obstacle(self) -> bool:
+        return False
 
 
 @dataclass

src/freeroute/board/search_tree.py

@@ -47,6 +47,9 @@ class TreeShape:
     routed: bool = False
     exact: Simplex | None = None
     seg: tuple | None = None  # (a: IntPoint, b: IntPoint, half_width: int)
+    #: which copper a keepout tile stops: "all", "wires" (a wire_keepout,
+    #: vias allowed) or "vias" (a via_keepout)
+    blocks: str = "all"
 
     def on_layer(self, layer: int) -> bool:
         return layer in self.layers
@@ -118,7 +121,9 @@ class ShapeSearchTree:
                     result.append(shape)
         return result
 
-    def clearance_conflict(self, box: IntBox, net_no: int, layer: int, clearance: int) -> bool:
+    def clearance_conflict(
+        self, box: IntBox, net_no: int, layer: int, clearance: int, kind: str = "wire"
+    ) -> bool:
         """True if placing ``box`` (of ``net_no`` on ``layer``) would come *closer
         than* ``clearance`` to a different net's tile on that layer (exact).
 
@@ -129,6 +134,8 @@ class ShapeSearchTree:
         for shape in self.overlapping(expanded):
             if shape.net_no == net_no or not shape.on_layer(layer):
                 continue
+            if shape.blocks != "all" and shape.blocks != kind + "s":
+                continue  # a wire-only keepout does not stop a via, and so on
             if shape.exact is not None:
                 if overlaps_2d(shape.exact, expanded):
                     return True

src/freeroute/dsn/model.py

@@ -170,6 +170,14 @@ class NetClass:
     via_rule: str | None = None
 
 
+@dataclass
+class Plane:
+    """A ``(plane <net> <shape>)``: a copper zone of that net (KiCad's zones)."""
+
+    net: str
+    shape: Shape
+
+
 @dataclass
 class Keepout:
     """A structure-level keepout area with its kind."""
@@ -187,6 +195,8 @@ class DsnBoard:
     resolution: Resolution = field(default_factory=Resolution)
     unit: str = "mil"
     layers: list[Layer] = field(default_factory=list)
+    #: copper zones, as planes of a net
+    planes: list[Plane] = field(default_factory=list)
     #: bounding-box boundary shape (layer ``pcb``), if present
     boundary: Shape | None = None
     #: outline shapes (layer ``signal``)

src/freeroute/dsn/reader.py

@@ -183,6 +183,11 @@ def _read_structure(node: SExp, board: DsnBoard) -> None:
             area = read_area(it)
             if area is not None:
                 board.keepouts.append(Keepout(area=area, kind="wire_keepout"))
+        elif head == "plane":
+            # (plane <net> <shape>): KiCad exports each zone this way
+            plane = _read_plane(it)
+            if plane is not None:
+                board.planes.append(plane)
         elif head == "place_keepout":
             area = read_area(it)
             if area is not None:
@@ -513,3 +518,19 @@ def parse_dsn(text: str) -> DsnBoard:
         # `wiring` and unknown scopes are intentionally ignored for now.
 
     return board
+
+
+def _read_plane(node: SExp):
+    """``(plane <net> (polygon <layer> <width> x y ...))`` -> :class:`Plane`."""
+    from .model import Plane
+
+    items = node.items
+    if not items or not isinstance(items[0], Token):
+        return None
+    net = items[0].text
+    for sub in items[1:]:
+        if isinstance(sub, SExp):
+            shape = read_shape(sub)
+            if shape is not None:
+                return Plane(net=net, shape=shape)
+    return None

src/freeroute/route/exact_router.py

@@ -143,10 +143,16 @@ def route_board_exact(
     for obstacle in board.get_obstacle_areas():
         if obstacle.layer not in signal_layers:
             continue
+        blocks = (
+            "all" if obstacle.blocks_wires and obstacle.blocks_vias
+            else "wires" if obstacle.blocks_wires else "vias"
+        )
         for tile in obstacle.tiles:
             box = tile.bounding_box()
             if not box.is_empty():
-                tree.insert(TreeShape(next(owner), -1, frozenset({obstacle.layer}), box))
+                tree.insert(
+                    TreeShape(next(owner), -1, frozenset({obstacle.layer}), box, blocks=blocks)
+                )
 
     via_layers = frozenset(signal_layers)
     accepted: dict[int, _Accepted] = {}
@@ -155,9 +161,12 @@ def route_board_exact(
     # 25-pin supply net costs that one connection, not the whole net.
     for net_no, wires, vias in sorted(result.connections, key=lambda c: c[0]):
         boxes = _copper_boxes(wires, vias, half_width, via_layers, via_half)
+        wire_count = len(_copper_boxes(wires, [], half_width, via_layers, via_half))
         if any(
-            tree.clearance_conflict(box, net_no, layer, clearance)
+            tree.clearance_conflict(
-            for box, box_layers in boxes
+                box, net_no, layer, clearance, "wire" if i < wire_count else "via"
+            )
+            for i, (box, box_layers) in enumerate(boxes)
             for layer in box_layers
         ) or (outline is not None and not all(outline.box_clear(b, edge) for b, _ in boxes)):
             continue  # exact-clearance conflict -> drop (may be recovered by shove)

src/freeroute/route/grid_router.py

@@ -30,7 +30,7 @@ import heapq
 import math
 
 from freeroute.board.board import BasicBoard
-from freeroute.board.items import ObstacleArea, Pin
+from freeroute.board.items import ConductionArea, ObstacleArea, Pin
 from freeroute.geometry import IntBox, IntPoint
 
 __all__ = ["GridRouter", "RouteResult", "route_board"]
@@ -102,6 +102,10 @@ class _Connection:
         "via_cells",
         "via_halo",
         "halo_nodes",
+        "a_group",
+        "b_group",
+        "a_end",
+        "b_end",
     )
 
     def __init__(self, index: int, net_no: int, a: Pin, b: Pin) -> None:
@@ -117,6 +121,12 @@ class _Connection:
         self.via_cells: list[Cell] = []
         self.via_halo: list[Cell] = []
         self.halo_nodes: list[Node] = []
+        # the pins and zones each end may use, and which pin the route ended
+        # on (None when it ended on a zone)
+        self.a_group: tuple[list[Pin], list] = ([a], [])
+        self.b_group: tuple[list[Pin], list] = ([b], [])
+        self.a_end: Pin | None = a
+        self.b_end: Pin | None = b
 
 
 class GridRouter:
@@ -192,6 +202,8 @@ class GridRouter:
         self._pad_block: dict[Node, set[int]] = {}
         self._pad_own: dict[Node, set[int]] = {}
         self._keepout: set[Node] = set()
+        self._via_keepout: set[Node] = set()
+        self._zone_cells: dict[int, list[Node]] = {}
         # per-connection occupancy (owner = connection index)
         self._cell_owner: dict[Node, int] = {}
         self._via_owner: dict[Cell, int] = {}
@@ -280,6 +292,8 @@ class GridRouter:
                     if self._inside_own_pad(cell, item.shape):
                         for layer in pin_layers:
                             self._pad_own.setdefault((*cell, layer), set()).add(net)
+            elif isinstance(item, ConductionArea):
+                continue  # a zone is copper of its net, not an obstacle
             elif isinstance(item, ObstacleArea):
                 if item.layer not in self.layers:
                     continue
@@ -291,12 +305,21 @@ class GridRouter:
                         continue
                     # the same distance the exact engine verifies against
                     for cell in self._cells_in_box(box, margin):
-                        self._keepout.add((*cell, item.layer))
+                        if item.blocks_wires:
+                            self._keepout.add((*cell, item.layer))
+                        if item.blocks_vias:
+                            self._via_keepout.add((*cell, item.layer))
 
     # --- occupancy cost -----------------------------------------------------
 
     def _enter_cost(
-        self, cell: Cell, layer: int, net_no: int, allow_ripup: bool, conns: list[_Connection]
+        self,
+        cell: Cell,
+        layer: int,
+        net_no: int,
+        allow_ripup: bool,
+        conns: list[_Connection],
+        wire_keepout: bool = True,
     ) -> float | None:
         """Cost to enter ``(cell, layer)`` for ``net_no``; ``None`` if blocked.
 
@@ -306,7 +329,7 @@ class GridRouter:
         already hit ``rip_cap`` (then it hardens into a wall).
         """
         node = (*cell, layer)
-        if node in self._keepout:
+        if wire_keepout and node in self._keepout:
             return None
         pads = self._pad_block.get(node)
         if pads and any(n != net_no for n in pads) and net_no not in self._pad_own.get(node, ()):
@@ -347,33 +370,38 @@ class GridRouter:
         """A through via needs its whole footprint free of other nets on every layer."""
         if cell in self._via_edge_block:
             return False
-        return all(
+        for c in self._via_cells(cell):
-            self._enter_cost(c, layer, net_no, False, conns) == 0.0
+            for layer in self.layers:
-            for c in self._via_cells(cell)
+                if (*c, layer) in self._via_keepout:
-            for layer in self.layers
+                    return False
-        )
+                if self._enter_cost(c, layer, net_no, False, conns, wire_keepout=False) != 0.0:
+                    return False
+        return True
 
     # --- A* search ----------------------------------------------------------
 
     def _search(
         self, conn: _Connection, allow_ripup: bool, conns: list[_Connection]
     ) -> list[Node] | None:
-        goal_cell = self._cell_of(conn.b.location)
+        goal_cell = self._group_target(conn.b_group)
-        starts = self._end_nodes(conn.a, conn.net_no, conns)
+        starts = self._group_ends(conn.a_group, conn.net_no, conns)
-        goals = self._end_nodes(conn.b, conn.net_no, conns)
+        goals = self._group_ends(conn.b_group, conn.net_no, conns)
         if not starts or not goals:
             return None
-        if starts & goals:
+        common = sorted(set(starts) & set(goals))
-            return [min(starts & goals)]
+        if common:
+            conn.a_end, conn.b_end = starts[common[0]], goals[common[0]]
+            return [common[0]]
         net_no = conn.net_no
 
         open_heap: list[tuple[float, Node]] = []
         g_score: dict[Node, float] = {}
         came_from: dict[Node, Node] = {}
         # a stub costs its length, so the nearest cell wins unless it is blocked
-        goal_stub = {n: self._stub_cost(conn.b, n) for n in goals}
+        goal_stub = {n: self._stub_cost(p, n) for n, p in goals.items() if p is not None}
         for s in sorted(starts):
-            g_score[s] = self._stub_cost(conn.a, s)
+            pin = starts[s]
+            g_score[s] = self._stub_cost(pin, s) if pin is not None else 0.0
             heapq.heappush(open_heap, (g_score[s] + self._h(s, goal_cell), s))
 
         # Via footprints are checked lazily: a layer change goes on the heap as
@@ -397,7 +425,9 @@ class GridRouter:
                 continue
             current = entry[1]
             if current in goals:
-                return _reconstruct(came_from, current)
+                path = _reconstruct(came_from, current)
+                conn.a_end, conn.b_end = starts.get(path[0]), goals[current]
+                return path
             cx, cy, cl = current
             base = g_score[current]
             for dx, dy in self._neighbours:
@@ -405,7 +435,7 @@ class GridRouter:
                 if not (0 <= cell[0] < self.cols and 0 <= cell[1] < self.rows):
                     continue
                 nxt = (*cell, cl)
-                if nxt in goals:
+                if nxt in goal_stub:  # a pin end; a zone end is entered normally
                     enter = goal_stub[nxt]
                 else:
                     enter = self._enter_cost(cell, cl, net_no, allow_ripup, conns)
@@ -459,6 +489,40 @@ class GridRouter:
                 return False
         return True
 
+    def _zone_nodes(self, zone) -> list[Node]:
+        """Cells of a zone where a via of this net fits inside its copper."""
+        key = id(zone)
+        if key not in self._zone_cells:
+            h = self.via_half
+            nodes = []
+            for tile in zone.tiles:
+                for cell in self._cells_in_box(tile.bounding_box(), 0):
+                    c = self._cell_center(cell)
+                    if all(
+                        zone.polygon.contains(IntPoint(c.x + dx, c.y + dy))
+                        for dx in (-h, h) for dy in (-h, h)
+                    ):
+                        nodes.append((*cell, zone.layer))
+            self._zone_cells[key] = sorted(set(nodes))
+        return self._zone_cells[key]
+
+    def _group_ends(self, group, net_no: int, conns) -> dict[Node, Pin | None]:
+        """End nodes of a group, each mapped to its pin (None for a zone cell)."""
+        ends: dict[Node, Pin | None] = {}
+        for pin in group[0]:
+            for node in sorted(self._end_nodes(pin, net_no, conns)):
+                ends.setdefault(node, pin)
+        for zone in group[1]:
+            for node in self._zone_nodes(zone):
+                ends.setdefault(node, None)
+        return ends
+
+    def _group_target(self, group) -> Cell:
+        if group[0]:
+            return self._cell_of(group[0][0].location)
+        box = group[1][0].bounding_box()
+        return self._cell_of(IntPoint((box.ll.x + box.ur.x) // 2, (box.ll.y + box.ur.y) // 2))
+
     def _stub_cost(self, pin: Pin, node: Node) -> float:
         c = self._cell_center(node[:2])
         dx, dy = abs(c.x - pin.location.x), abs(c.y - pin.location.y)
@@ -523,8 +587,11 @@ class GridRouter:
                 if c not in self._via_owner:
                     self._via_owner[c] = conn.index
                     conn.via_halo.append(c)
-        for pin, (layer, cells) in ((conn.a, wire_segs[0]), (conn.b, wire_segs[-1])) if wire_segs else ():
+        ends = ((conn.a_end, wire_segs[0], 0), (conn.b_end, wire_segs[-1], -1)) if wire_segs else ()
-            cell = cells[0] if pin is conn.a else cells[-1]
+        for pin, (layer, cells), at in ends:
+            if pin is None:
+                continue  # ended on a zone: no stub
+            cell = cells[at]
             for c in self._stub_cells(pin.location, cell):
                 node = (*c, layer)
                 if node not in self._cell_owner:
@@ -533,10 +600,10 @@ class GridRouter:
         conn.wires = []
         for idx, (layer, cells) in enumerate(wire_segs):
             points = [self._cell_center(c) for c in cells]
-            if idx == 0:
+            if idx == 0 and conn.a_end is not None:
-                points.insert(0, conn.a.location)
+                points.insert(0, conn.a_end.location)
-            if idx == len(wire_segs) - 1:
+            if idx == len(wire_segs) - 1 and conn.b_end is not None:
-                points.append(conn.b.location)
+                points.append(conn.b_end.location)
             points = _simplify(points)
             if len(points) >= 2:
                 conn.wires.append((layer, points))
@@ -624,12 +691,19 @@ class GridRouter:
 
     def _build_connections(self) -> list[_Connection]:
         pins_by_net = self._pins_by_net()
+        zones_by_net: dict[int, list] = {}
+        for zone in self.board.get_conduction_areas():
+            if zone.layer in self.layers and zone.net_nos:
+                zones_by_net.setdefault(zone.net_nos[0], []).append(zone)
         conns: list[_Connection] = []
+        nets = set(pins_by_net) | set(zones_by_net)
         # deterministic: fewer-pin nets first, then by net number
-        for net_no in sorted(pins_by_net, key=lambda n: (len(pins_by_net[n]), n)):
+        for net_no in sorted(nets, key=lambda n: (len(pins_by_net.get(n, [])), n)):
-            pins = pins_by_net[net_no]
+            groups = _connected_groups(pins_by_net.get(net_no, []), zones_by_net.get(net_no, []))
-            for a, b in zip(pins, pins[1:], strict=False):
+            for ga, gb in zip(groups, groups[1:], strict=False):
-                conns.append(_Connection(len(conns), net_no, a, b))
+                conn = _Connection(len(conns), net_no, _first(ga[0]), _first(gb[0]))
+                conn.a_group, conn.b_group = ga, gb
+                conns.append(conn)
         return conns
 
     def _pins_by_net(self) -> dict[int, list[Pin]]:
@@ -660,6 +734,56 @@ class GridRouter:
         return result
 
 
+def _first(items):
+    return items[0] if items else None
+
+
+def _pin_touches_zone(pin: Pin, zone) -> bool:
+    """A pad on the zone's layer whose centre or a corner lies in the zone."""
+    if zone.layer not in pin.layers or zone.polygon is None:
+        return False
+    if zone.polygon.contains(pin.location):
+        return True
+    box = pin.shape.bounding_box() if pin.shape is not None else None
+    if box is None:
+        return False
+    corners = (box.ll, IntPoint(box.ur.x, box.ll.y), box.ur, IntPoint(box.ll.x, box.ur.y))
+    return any(zone.polygon.contains(c) for c in corners)
+
+
+def _connected_groups(pins: list[Pin], zones: list) -> list[tuple[list[Pin], list]]:
+    """Pins and zones of one net that copper already joins: a pad in a zone
+    is connected to it, and two zones sharing a pad are one. Only the groups
+    need routing between them. Pin groups come first, in pin order."""
+    parent = list(range(len(pins) + len(zones)))
+
+    def find(i: int) -> int:
+        while parent[i] != i:
+            parent[i] = parent[parent[i]]
+            i = parent[i]
+        return i
+
+    for j, zone in enumerate(zones):
+        for i, pin in enumerate(pins):
+            if _pin_touches_zone(pin, zone):
+                parent[find(i)] = find(len(pins) + j)
+    groups: dict[int, tuple[list[Pin], list]] = {}
+    order: list[int] = []
+    for i, pin in enumerate(pins):
+        root = find(i)
+        if root not in groups:
+            groups[root] = ([], [])
+            order.append(root)
+        groups[root][0].append(pin)
+    for j, zone in enumerate(zones):
+        root = find(len(pins) + j)
+        if root not in groups:
+            groups[root] = ([], [])
+            order.append(root)
+        groups[root][1].append(zone)
+    return [groups[r] for r in order]
+
+
 def _split_path(path: list[Node]) -> tuple[list[tuple[int, list[Cell]]], list[Cell]]:
     """Split a node path into per-layer wire segments and via cells."""
     wires: list[tuple[int, list[Cell]]] = []

tests/route/test_real_board_geometry.py

@@ -94,3 +94,47 @@ def test_heuristic_weight_bounds_route_length():
     shortest = length(1.0)
     assert shortest > 0
     assert length(2.0) <= 2.0 * shortest
+
+
+# --- copper zones (DSN planes) -----------------------------------------------
+# rc4 power stage: pads inside "keep router off" pours connect through the pour,
+# and freeroute, not knowing zones, dropped every such connection.
+
+_ZONE = "(plane N (polygon F.Cu 0  4000 -4000  10000 -4000  10000 -10000  4000 -10000  4000 -4000))"
+_NO_TRACKS = "(wire_keepout \"pour\" (polygon F.Cu 0  4000 -4000  10000 -4000  10000 -10000  4000 -10000))"
+
+
+def _zone_board():
+    places = "(place P1 5500 -7000 front 0) (place P2 8500 -7000 front 0) (place P3 16000 -16000 front 0)"
+    return parse_dsn(_dsn(f"(component P {places})", "(net N (pins P1-1 P2-1 P3-1))", _ZONE + " " + _NO_TRACKS))
+
+
+def test_planes_are_read_and_are_not_obstacles():
+    dsn = _zone_board()
+    assert [(p.net, p.shape.layer) for p in dsn.planes] == [("N", "F.Cu")]
+    board = build_board(dsn)
+    assert len(board.get_conduction_areas()) == 1
+    assert all(not a.is_obstacle() or a.name == "pour" for a in board.get_obstacle_areas())
+
+
+def test_pads_in_one_zone_need_no_route_between_them():
+    from freeroute.route.grid_router import _connected_groups
+
+    board = build_board(_zone_board())
+    pins = sorted(board.get_pins(), key=lambda p: p.component_ref)
+    groups = _connected_groups(pins, board.get_conduction_areas())
+    assert [sorted(p.component_ref for p in g[0]) for g in groups] == [["P1", "P2"], ["P3"]]
+
+
+def test_a_pad_reaches_a_zone_under_a_no_tracks_area_by_a_via():
+    dsn = _zone_board()
+    result, scale, names = route_dsn_board_exact(dsn)
+    net = next(iter(result.routed_net_numbers))
+    assert result.result.vias.get(net)  # it had to drop into the zone
+    board = build_board(dsn)
+    pour = next(a for a in board.get_obstacle_areas() if a.name == "pour")
+    f_cu = names.index("F.Cu")
+    for layer, pts in result.result.wires[net]:
+        if layer == f_cu:  # no track runs inside the no-tracks area
+            assert not any(t.contains(p) and not t.bounding_box().is_empty()
+                           for t in pour.tiles for p in pts[1:-1])