diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 0d6b1ce..dd772ed 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -214,7 +214,8 @@ receiver as the eventual real answer.
 ## 5. LA is not "SF but more data"
 
 SF is 0.20° × 0.36°. At the 45 m cells the SF heightfield uses, that is 336k
-lattice points and a 1.0 s build.
+lattice points and a 1.0 s build. (The pack has since grown to the whole Bay
+Area: 0.53M points and about 2.3 s.)
 
 LA + Orange County + Riverside is roughly 0.5° × 1.9° — about **14× the area**.
 The same approach would be 4.6M lattice points and a mesh nobody can load. This
@@ -293,7 +294,8 @@ resolutions:
   puts one scene unit at ~94 m with 3.6× vertical exaggeration; an office renders
   at 1 unit = 1 m. There are two scenes over one renderer, and the city scene is
   *retained and paused* when you step inside rather than disposed — rebuilding
-  its 336,864-point heightfield costs about a second on the way back out.
+  its 0.53M-point heightfield costs about two and a half seconds on the way back
+  out.
 - **A person at a desk is not a `Marker`.** A marker is geographic — it has a
   lat/lng. Presence binds to a **seat id** and never to a coordinate, which is
   what lets the office geometry be public and open-source while who is sitting
diff --git a/CONTRACT.md b/CONTRACT.md
index be9c380..68a9537 100644
--- a/CONTRACT.md
+++ b/CONTRACT.md
@@ -37,8 +37,9 @@ asserting `GET /api/v1/health` → 200.
 ## 1. Stage and scene lifecycle
 
 Two designs both created `src/engine/stage.ts` with opposite lifecycles. The
-retention argument wins on measured cost: SF's heightfield is 484 × 696 =
-336,864 lattice points and `world.ts` records a ~1.0 s build. Disposing the city
+retention argument wins on measured cost: the Bay Area's heightfield is 0.53M
+lattice points and about 2.3 s to build — it was 336,864 and ~1.0 s when the
+pack was San Francisco alone, and it grew, which is the point. Disposing the city
 every time someone steps into an office and paying a second of rebuild on the
 way out is not acceptable.
 
diff --git a/server/package.json b/server/package.json
index 3db1ed9..d43ca93 100644
--- a/server/package.json
+++ b/server/package.json
@@ -2,7 +2,7 @@
   "name": "@lumbridge/tera-api",
   "version": "0.1.0",
   "private": true,
-  "description": "The one Tera API. Health, flights, weather, markers and office packs on 127.0.0.1:8431.",
+  "description": "The one Tera API. Health, flights, weather, markers, office packs and session on 127.0.0.1:8431.",
   "license": "Apache-2.0",
   "type": "module",
   "main": "src/index.ts",
diff --git a/src/cities/socal.ts b/src/cities/socal.ts
index 6302c5e..bd143fb 100644
--- a/src/cities/socal.ts
+++ b/src/cities/socal.ts
@@ -3088,12 +3088,18 @@ export const SOCAL_CITY: City = {
   /**
    * 391 m to the scene unit, against San Francisco's 94.
    *
-   * Not a stylistic choice. `scene.ts` caps the orbit at 340 units from the
-   * target and `cityDaylight` closes its fog at 460, so however large a city is
-   * on the ground it has to end up roughly the same size in scene units or it
-   * cannot be looked at. The board this produces is 393 by 308 units — a little
-   * wider and deeper than San Francisco's 331 by 230, which is about as far as
-   * the camera will stretch.
+   * The board this produces is 393 by 308 units, against the Bay Area's 1003 by
+   * 830 — a metro four times the area rendered on a third of the board, which is
+   * why one instance here is a city block rather than a building.
+   *
+   * This used to be forced rather than chosen: `scene.ts` capped the orbit at
+   * 340 units and `cityDaylight` closed its fog at 460, both tuned when San
+   * Francisco was the only city, so however large a place was on the ground it
+   * had to come out roughly San Francisco's size in scene units or it could not
+   * be looked at. Both now derive from the board, so a pack is free to pick its
+   * own scale. This one keeps 285 because the numbers below — lot size, hill
+   * radii, bridge spans — were all authored against it, not because the engine
+   * still insists.
    */
   latScale: 285,
 
diff --git a/src/engine/scene.ts b/src/engine/scene.ts
index 0821d17..11ca34c 100644
--- a/src/engine/scene.ts
+++ b/src/engine/scene.ts
@@ -13,8 +13,8 @@
  * that ought to be here — is the city itself: which layers go in the scene,
  * where a chapter puts the camera, and what a pick means. An office builds the
  * same two pieces with its own answers and swaps in on the same `Stage`, which
- * keeps this city alive and paused rather than rebuilding its ~1.0 s
- * heightfield on the way back. See CONTRACT.md §1.
+ * keeps this city alive and paused rather than rebuilding its heightfield — for
+ * the Bay Area, about 2.3 s — on the way back. See CONTRACT.md §1.
  */
 
 import * as THREE from "three";
@@ -113,7 +113,7 @@ export function createScene(canvas: HTMLCanvasElement, options: SceneOptions): S
     shadowExtent: boardSpan * 0.75,
     shadowFar: boardSpan * 2.2,
   });
-  kit.applyLighting(options.lighting ?? cityDaylight(pal));
+  kit.applyLighting(options.lighting ?? cityDaylight(pal, boardSpan));
 
   scene.add(createWater(world));
   scene.add(createShorePlates(world));
@@ -254,12 +254,24 @@ export function createScene(canvas: HTMLCanvasElement, options: SceneOptions): S
  * It exists so the engine renders with no server, no clock and no config, which
  * is the acceptance test the whole repo is held to.
  */
-export function cityDaylight(palette: ScenePalette): LightingState {
+export function cityDaylight(palette: ScenePalette, boardSpan = 230): LightingState {
   return {
     sun: { direction: [-0.632, 0.717, 0.295], color: 0xfff3e0, intensity: 2.1 },
     hemisphere: { sky: 0xdcecf7, ground: 0x6b6f5e, intensity: 1.05 },
     ambient: { color: 0xffffff, intensity: 0.32 },
     sky: { top: palette.skyTop, horizon: palette.skyHorizon },
-    fog: { color: palette.skyHorizon, near: 210, far: 460 },
+    // Scaled to the board for the same reason the camera is, and it was the same
+    // bug: 210/460 were tuned when San Francisco's 230-unit board was the only
+    // one, and on the Bay Area's 1003 units they close the fog well inside the
+    // city. The camera sits about 0.6 spans out on a whole-board view, so a fog
+    // that starts nearer than that is behind the viewer's own shoulder.
+    //
+    // The default keeps the original numbers exactly, for a caller that has a
+    // palette but no world.
+    fog: {
+      color: palette.skyHorizon,
+      near: boardSpan * 0.91,
+      far: boardSpan * 2,
+    },
   };
 }
diff --git a/src/interiors/officeScene.ts b/src/interiors/officeScene.ts
index 41bde52..56da1f7 100644
--- a/src/interiors/officeScene.ts
+++ b/src/interiors/officeScene.ts
@@ -6,8 +6,9 @@
  * The renderer and the loop live in `Stage`; the camera, controls, flights and
  * picking live in a `SceneKit`; what is left here is the office itself. Swap it
  * in with `stage.setScene(office)` and the city is *paused, not disposed* —
- * rebuilding SF's 336,864-point heightfield on the way back out costs about a
- * second, which is the measurement CONTRACT.md §1 is built on.
+ * rebuilding the Bay Area's 0.53M-point heightfield on the way back out costs
+ * about two and a half seconds, which is the measurement CONTRACT.md §1 is
+ * built on.
  *
  * Whoever builds one of these disposes it. `Stage` disposes nothing it did not
  * create, and the city handle's `dispose()` does not reach in here.