diff --git a/THREADS.md b/THREADS.md
index b562495..5efd768 100644
--- a/THREADS.md
+++ b/THREADS.md
@@ -15,5 +15,7 @@ Format: `[lane letter] YYYY-MM-DD — note`
 [E] 2026-07-16 — contract, garden_bed: all 3 damage states ship in ONE glb as sibling nodes `plants_full` / `plants_tattered` / `plants_dead` (full visible, rest hide_render). Lane A: toggle .visible, don't reload — instant swap, no pop-in. Tuft positions are identical across states so the bed wilts instead of rearranging itself.
 [E] 2026-07-16 — debris in web/world/models/debris/, copied verbatim from the library and scale-checked: BlueCrate_v2 0.36×0.36×0.29, BlackTub_v2 + WhiteTub_v2 0.36×0.54×0.20, WoodenBin_v2 0.35×0.36×0.31 m — all plausible real-world sizes. Plus tramp_01_v1.glb (2.96×2.96×0.78, mass_hint 45) because every Australian storm produces one airborne trampoline. NOTE: §0's *_v1.glb rule beats §5-E's "tramp_01.glb" spelling — Lane C, glob the dir rather than hardcoding names.
 [E] 2026-07-16 — grass is a texture, not geometry (§5-E item 9): web/world/models/textures/grass_atlas.png, 512², 2×2 tufts, alpha. Lane A instances billboards from it.
+[E] 2026-07-16 — ⚠️ FOR LANE A + LANE C, bounding boxes: `THREE.Box3.setFromObject(obj)` expands each mesh's LOCAL box by the world matrix, so a node carrying a rotation reports an inflated box — and that's what three uses for frustum culling. Blender's obj.bound_box has the identical trap (it cost me an hour of chasing phantom "failures"). Fixed at source: join_group() now bakes rotation into the vertices, so every node's local box is axis-aligned and tight. Before the fix three reported tramp_01 as 3.29×1.27 m vs its true 2.96×0.78. You can use the default Box3 safely now — but if you ever measure geometry yourself, measure VERTICES, not bound_box corners.
+[E] 2026-07-16 — landed tools/assetcheck/ (README + assets_in_three.html): loads every GLB through three.js r175 GLTFLoader and asserts Y-up, node survival, and that branch_anchor_01 lands at a sane +Y world position. This exists because the Blender round-trip CANNOT catch an axis bug — it exports Z-up→Y-up and imports Y-up→Z-up, so a broken export_yup flips back and passes. Currently green: 16/16 + anchors, `branch_anchor_01` at (-0.96, 3.64, -1.46). Lane A: once server.py + vendor/ land, this wants to live next to selftest.html — happy for you to fold it in, it reads expectations from asset_report.json so it stays in sync by itself.
 [E] 2026-07-16 — added a root .gitignore (thumbs/, *.blend, *.fbx per §0). Unowned file — Lane A, fold it into yours if you'd rather own it.
 [E] 2026-07-16 — open q for Lane A: does house_yardside at 9.20 m wide sit right on the north edge of a 30×20 m yard, or do you want a wider/second variant? Cheap to re-cut — it's one function in the script.
diff --git a/tools/assetcheck/README.md b/tools/assetcheck/README.md
new file mode 100644
index 0000000..0f194e5
--- /dev/null
+++ b/tools/assetcheck/README.md
@@ -0,0 +1,50 @@
+# assets_in_three.html — verify the GLBs in the real consumer
+
+`build_yard_assets.py` already re-imports every GLB into Blender and asserts
+dims, tri budget, and node names. That is necessary but **structurally cannot
+catch an axis error**: Blender exports Z-up→Y-up and imports Y-up→Z-up, so a
+broken `export_yup` flips back on the way in and round-trips green. Only
+something that reads glTF natively can prove the file is right.
+
+This page is that check. It loads each GLB with three.js r175's `GLTFLoader` and
+asserts:
+
+- **Y-up**: a Blender asset measuring `(dx, dy, dz)` must arrive as `(dx, dz, dy)`.
+- **node survival**: `branch_anchor_*`, `fascia_anchor_*`, `plants_*` etc. still
+  exist after the export — glTF has no "empty", anchors arrive as bare
+  `Object3D`, and exporters have been known to prune childless nodes.
+- **anchors are usable**: `branch_anchor_01` resolves to a sane world position
+  with height on +Y.
+
+Expectations are read from `tools/blender/asset_report.json`, so this stays in
+sync with the factory automatically.
+
+## Why it uses the default (non-precise) Box3
+
+`THREE.Box3.setFromObject(obj)` expands each mesh's **local** bounding box by the
+world matrix, so a node carrying a rotation reports an inflated box. That is the
+same trap Blender's `obj.bound_box` sets, and it is what three uses for frustum
+culling. `join_group()` therefore bakes rotation into the vertices so the local
+box is axis-aligned and tight. Passing `precise: true` here would hide exactly
+the regression this page exists to catch — so don't.
+
+Before that fix, three reported `tramp_01` as 3.29 × 1.27 m against a true
+2.96 × 0.78 m.
+
+## Running it
+
+Needs three.js on `/world/vendor/` and the models on `/models/`. Once Lane A's
+`server.py` lands, serve `web/` and this can move next to `selftest.html`
+(Lane A: happy to fold it in — see THREADS).
+
+Until then, the standalone recipe:
+
+```sh
+D=$(mktemp -d) && mkdir -p "$D/world"
+ln -s ~/Documents/90sDJsim/web/world/vendor        "$D/world/vendor"
+ln -s "$PWD/web/world/models"                      "$D/models"
+ln -s "$PWD/tools/blender/asset_report.json"       "$D/asset_report.json"
+cp tools/assetcheck/assets_in_three.html           "$D/index.html"
+python3 -m http.server 8805 --directory "$D"
+# open http://127.0.0.1:8805 — look for "SUMMARY: ALL PASS IN THREE.JS"
+```
diff --git a/tools/assetcheck/assets_in_three.html b/tools/assetcheck/assets_in_three.html
new file mode 100644
index 0000000..3afa682
--- /dev/null
+++ b/tools/assetcheck/assets_in_three.html
@@ -0,0 +1,82 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Lane E — GLB check in the real consumer (three.js r175)</title>
+<style>
+  body { background:#14161a; color:#dfe3e8; font:13px/1.5 ui-monospace,Menlo,monospace; padding:16px; }
+  .pass { color:#7fd67f; } .fail { color:#ff6b6b; } h1 { font-size:15px; color:#9fb4c7; }
+</style>
+<h1>GLB verification — loaded by three.js GLTFLoader, not Blender</h1>
+<pre id="out">loading…</pre>
+
+<script type="importmap">
+{ "imports": { "three": "/world/vendor/three.module.js",
+  "three/addons/": "/world/vendor/addons/" } }
+</script>
+<script type="module">
+import * as THREE from 'three';
+import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
+
+const out = document.getElementById('out');
+const log = [];
+const say = (s, cls) => {
+  log.push(s);
+  out.innerHTML += `<span class="${cls || ''}">${s}</span>\n`;
+  console.log(s);
+};
+
+const report = await (await fetch('/asset_report.json')).json();
+const loader = new GLTFLoader();
+let fails = 0;
+
+say(`three.js r${THREE.REVISION}  |  ${report.assets.length} assets\n`);
+
+for (const a of report.assets) {
+  let gltf = null;
+  for (const dir of ['/models/', '/models/debris/']) {
+    try { gltf = await loader.loadAsync(`${dir}${a.name}_v1.glb`); break; } catch (e) {}
+  }
+  if (!gltf) { say(`[FAIL] ${a.name.padEnd(16)} could not load`, 'fail'); fails++; continue; }
+
+  const size = new THREE.Vector3();
+  new THREE.Box3().setFromObject(gltf.scene).getSize(size);
+
+  // The whole point of this page. Blender is Z-up, glTF is Y-up, so a Blender
+  // asset measuring (dx, dy, dz) MUST arrive here as (dx, dz, dy). A Blender
+  // re-import can never catch a broken export_yup — it just flips it back.
+  const [bx, by, bz] = a.dims;
+  const exp = [bx, bz, by];
+  const got = [size.x, size.y, size.z];
+  const axisOk = got.every((v, i) => Math.abs(v - exp[i]) < 0.02);
+
+  const names = [];
+  gltf.scene.traverse(o => names.push(o.name));
+  const missing = a.nodes.filter(n => !names.includes(n));
+
+  const ok = axisOk && missing.length === 0;
+  if (!ok) fails++;
+  say(`[${ok ? 'PASS' : 'FAIL'}] ${a.name.padEnd(16)} ` +
+      `${got.map(v => v.toFixed(2)).join(' x ')} m (Y-up)`, ok ? 'pass' : 'fail');
+  if (!axisOk) say(`        axis/scale: expected ${exp.map(v => v.toFixed(2)).join(' x ')}`, 'fail');
+  if (missing.length) say(`        nodes lost in three.js: ${missing.join(', ')}`, 'fail');
+}
+
+// Empties are the risky part: glTF has no "empty", they arrive as bare Object3D
+// nodes, and exporters have been known to prune childless ones. Anchors ARE the
+// contract, so prove one survives with a usable world position.
+const t = await loader.loadAsync('/models/tree_gum_01_v1.glb');
+const anchor = t.scene.getObjectByName('branch_anchor_01');
+if (anchor) {
+  t.scene.updateWorldMatrix(true, true);
+  const p = new THREE.Vector3().setFromMatrixPosition(anchor.matrixWorld);
+  const upright = p.y > 1.0 && p.y < 6.0;
+  if (!upright) fails++;
+  say(`\n[${upright ? 'PASS' : 'FAIL'}] branch_anchor_01 world pos ` +
+      `(${p.x.toFixed(2)}, ${p.y.toFixed(2)}, ${p.z.toFixed(2)}) — ` +
+      `${upright ? 'height is on +Y, anchors are usable' : 'height is NOT on +Y!'}`,
+      upright ? 'pass' : 'fail');
+} else { fails++; say('\n[FAIL] branch_anchor_01 missing entirely', 'fail'); }
+
+say(`\nSUMMARY: ${fails === 0 ? 'ALL PASS IN THREE.JS' : fails + ' FAILURES'}`,
+    fails === 0 ? 'pass' : 'fail');
+window.__done = true; window.__fails = fails;
+</script>
diff --git a/tools/blender/build_yard_assets.py b/tools/blender/build_yard_assets.py
index 93f36e9..16c950e 100644
--- a/tools/blender/build_yard_assets.py
+++ b/tools/blender/build_yard_assets.py
@@ -280,6 +280,17 @@ def join_group(objs, name, parent=None):
             print(f"    ! join failed for {name}: {e}")
     res = _active()
     res.name = name
+    # Bake the rotation objs[0] contributed into the vertices, so the node's
+    # LOCAL box is world-axis-aligned and therefore tight.
+    #
+    # This is not cosmetic. THREE.Box3.setFromObject() (and Blender's
+    # obj.bound_box, and three's frustum culling) expand the LOCAL bounding box
+    # by the world matrix. A joined node inherits objs[0]'s rotation — for an
+    # arc, that's half a segment step off-axis — so every consumer computing
+    # bounds the normal way would over-report these assets by ~11% and cull
+    # them late. Verified against three.js r175: without this, Box3 reports
+    # tramp_01 as 3.29 x 1.27 instead of its true 2.96 x 0.78.
+    _apply_transform(res, rotation=True, scale=True)
     if parent is not None:
         res.parent = parent
     return res
diff --git a/tools/blender/contact_sheet.png b/tools/blender/contact_sheet.png
index 0e31d12..b603db2 100644
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diff --git a/web/world/models/carabiner_v1.glb b/web/world/models/carabiner_v1.glb
index 3f32677..a4ff4f2 100644
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diff --git a/web/world/models/debris/tramp_01_v1.glb b/web/world/models/debris/tramp_01_v1.glb
index 5faec4b..1794d76 100644
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diff --git a/web/world/models/garden_bed_v1.glb b/web/world/models/garden_bed_v1.glb
index c76d046..accfc9d 100644
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diff --git a/web/world/models/gate_v1.glb b/web/world/models/gate_v1.glb
index 2efb33c..2c84e44 100644
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diff --git a/web/world/models/house_yardside_v1.glb b/web/world/models/house_yardside_v1.glb
index b41a64d..547a98c 100644
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diff --git a/web/world/models/shackle_v1.glb b/web/world/models/shackle_v1.glb
index f55952f..08e0739 100644
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diff --git a/web/world/models/shed_01_v1.glb b/web/world/models/shed_01_v1.glb
index ceb0e14..8cceea5 100644
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diff --git a/web/world/models/tree_gum_01_v1.glb b/web/world/models/tree_gum_01_v1.glb
index 980831a..f88b844 100644
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diff --git a/web/world/models/tree_gum_02_v1.glb b/web/world/models/tree_gum_02_v1.glb
index 4130523..e0705a7 100644
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