GPT-6.1 Sol (effort default (no reasoning-effort override) · thinking on) on Model a game-ready low-poly 3D prop from a one-line brief, within a tight triangle budget
OGPT-6.1 Soldefault · thinking on · Codex CLI 0.163.0 (codex exec --json) · cloud · 2026-10-22 · by @bobsiopener
- Estimated cost
- $0.04
- Wall time
- 1m
- Human step-ins
- 0
- Outcome
- Pass
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Summary
Exact prompt
# Game-ready low-poly 3D asset from a one-line brief `asset.json` holds a one-line `description` of a game prop plus its art brief: `triangle_budget`, `min_segments` and `parts`. Write `solve.py` (Python 3 standard library only; no Blender or other 3D tools are needed or assumed). `python solve.py input.json answer.json` (first argument unused; read `asset.json` from the current directory) writes `asset.obj` and `answer.json`. Fresh briefs (other props) are generated when scoring. ## Geometry rules (metres, +Y up, ground plane y = 0) 1. Shapes: `box` with `size` [x, y, z]; `cylinder` (`radius`, `height`); `frustum` (`radius_bottom`, `radius_top`, `height`); `cone` (`radius`, `height`, apex at the top centre). Round shapes have their axis along +Y. 2. Placement: a part with `"on": "ground"` has its bottom at y = 0 and its x/z centre at (0, 0) + `offset` [dx, dz] (default [0, 0]). A part `"on": "<name>"` has its bottom at the top (max y) of that part and its x/z centre at the centre of that part's bounding box + `offset`. If the named part is an array, use the bounding box of all its instances. 3. `array` `{"count": 4, "layout": "corners", "inset": s}`: four instances standing on the parent's top, centred at the parent's bounding-box x/z corners moved inward by `s` on both axes, in the order (-x,-z), (+x,-z), (+x,+z), (-x,+z). 4. Each part's bounding box must equal the ideal shape's bounding box (within 1e-4), so round shapes need a ring vertex on each of the +x, -x, +z and -z axes. 5. Round shapes use one ring of N segments per circle, N >= `min_segments` and a multiple of 4. The whole asset must use at most `triangle_budget` triangles (it is tight: spend triangles carefully). 6. Every part is a separate closed, manifold mesh: every edge shared by exactly two of that part's triangles, consistent winding, counter-clockwise when seen from outside (outward normals, positive signed volume), no degenerate or zero-area triangles. Vertices may be shared or duplicated; edges are compared by position. ## asset.obj Wavefront OBJ, `v x y z` and triangle-only `f` lines. One `o <name>` per part; array instances are `o <name>.1` .. `o <name>.4`. No other objects. ## answer.json `{"triangles": total, "parts": {object name: {"triangles": n, "bounds": [[minx, miny, minz], [maxx, maxy, maxz]]}}}`; counts must match asset.obj. ## Scoring Hidden checks (partial credit; all must pass), computed by parsing your OBJ: `obj_parses_named_parts_triangles`, `triangle_budget_and_ring_segments`, `part_bounds_and_stacking`, `closed_manifold_consistent_winding`, `outward_normals_positive_volume`, `answer_json_matches_mesh` on the given brief; `fresh_run_1`, `fresh_run_2` (the first five checks on new briefs). 30-second limit per run.
Getting a mesh that renders is easy; getting every part closed, outward-facing, exactly sized and under a budget with 2 spare triangles needs real geometry reasoning. Original benchmark task written for usecaserank.com. Headless, offline run on a reproducible fixture. Cost shown is a list-price API-equivalent estimate (run on a ChatGPT subscription, not billed).
Success criteria: 1. obj_parses_named_parts_triangles 2. triangle_budget_and_ring_segments 3. part_bounds_and_stacking 4. closed_manifold_consistent_winding 5. outward_normals_positive_volume 6. answer_json_matches_mesh 7. fresh_run_1 8. fresh_run_2
Setup notes: Use Case Scout batch13 case n02-game-asset-mesh (offline fixture). Prepared with batch13/prepare.sh on the shared box; only TASK.md + starting files were copied to the agent machine, hidden key/tests stayed on the box. Prompt = TASK.md verbatim on stdin. Flags: --json -s workspace-write --skip-git-repo-check --ephemeral --ignore-user-config --ignore-rules -C <workdir>. Scored on the box with the scout's scorer: `python score.py WORKDIR KEYDIR`. Single run, no retries. User-level AGENTS.md (846 bytes, sha256 83ec4fe50da8) may have been in context; --ignore-user-config does not document excluding it. Visual output (asset.obj) rendered offline to PNG with google-chrome headless, network blocked, 1280x800 at ~3 s after load. Serving model not confirmed: requested via -m; the event log does not echo the serving model id. Price source is secondary (pricing.json verification='secondary', https://www.actuia.com/en/news/ai-api-pricing-in-october-2026-050-to-50-for-output/), not an official OpenAI price page. Score: 8/8. Cost is an ESTIMATE: measured tokens x pricing.json list price (ChatGPT plan, nothing billed); input_tokens include cached reads; output_tokens include reasoning tokens. Tool calls 4 (1 failed, recovered). Single run.
Estimated cost List-price estimate; not actually billed.
Output
Metrics
- Estimated cost
- $0.04
- Wall time
- 1m
- Human step-ins
- 0
- Turns
- 1
| Model | Input tok | Output tok | Cost |
|---|---|---|---|
| OGPT-6.1 Solopenai/gpt-6.1-soleffort default (no reasoning-effort override) · thinking on | 69,971 | 2,501 | $0.04 |
Reproduce this run
- Use the use case prompt on the use case page.
- Same setup: GPT-6.1 Sol (openai/gpt-6.1-sol, effort default (no reasoning-effort override) · thinking on) via
Codex CLI 0.163.0 (codex exec --json), cloud. - It counts as a success only if it meets every success criterion: 1. obj_parses_named_parts_triangles 2. triangle_budget_and_ring_segments 3. part_bounds_and_stacking 4. closed_manifold_consistent_winding 5. outward_normals_positive_volume 6. answer_json_matches_mesh 7. fresh_run_1 8. fresh_run_2
- Log model, tokens, wall time, human step-ins and the evidence log, then submit it as a reproduction. A different model? Submit a head-to-head rerun.
How runs are scored: Methodology.
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Automated checks
Trust 80% comes from these checks (how Trust % works).
- Run date is not in the future : passed
- Model is in the dated pricing table : passed
- Cost recomputed from tokens matches : passed
- Cached tokens are consistent : passed
- Output throughput is plausible : passed
- Autonomy matches step-ins : passed
- Step-ins do not exceed turns : passed
- Retries agree with first-try result : passed
- Evidence log SHA-256 matches : passed
- Evidence log is substantial : passed
Evidence log
{"type": "thread.started", "thread_id": "01a16412-2301-7bc0-9b64-1c32dafb9a49"}
{"type": "turn.started"}
{"type": "item.completed", "item": {"id": "item_0", "type": "agent_message", "text": "I\u2019ll inspect the brief, then build a mesh generator that uses the minimum allowed ring segments to stay within the triangle budget."}}
{"type": "item.started", "item": {"id": "item_1", "type": "command_execution", "command": "/bin/bash -lc \"pwd && rg --files -g 'asset.json' -g 'AGENTS.md' -g 'solve.py'\"", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_1", "type": "command_execution", "command": "/bin/bash -lc \"pwd && rg --files -g 'asset.json' -g 'AGENTS.md' -g 'solve.py'\"", "aggregated_output": "/home/bob/usecase-runs/batch/out/gpt-6.1-sol/133_n02/work\nasset.json\n", "exit_code": 0, "status": "completed"}}
{"type": "item.started", "item": {"id": "item_2", "type": "command_execution", "command": "/bin/bash -lc 'cat asset.json'", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_2", "type": "command_execution", "command": "/bin/bash -lc 'cat asset.json'", "aggregated_output": "{\n \"description\": \"A low-poly street lantern: stone base, iron post, glass lamp box and a pointed cap.\",\n \"units\": \"metres, +Y up, ground plane y = 0\",\n \"triangle_budget\": 92,\n \"min_segments\": 12,\n \"parts\": [\n {\n \"name\": \"base\",\n \"shape\": \"box\",\n \"size\": [\n 0.44,\n 0.27,\n 0.55\n ],\n \"on\": \"ground\"\n },\n {\n \"name\": \"post\",\n \"shape\": \"cylinder\",\n \"radius\": 0.06,\n \"height\": 1.38,\n \"on\": \"base\"\n },\n {\n \"name\": \"lamp\",\n \"shape\": \"box\",\n \"size\": [\n 0.33,\n 0.31,\n 0.28\n ],\n \"on\": \"post\"\n },\n {\n \"name\": \"cap\",\n \"shape\": \"cone\",\n \"radius\": 0.24,\n \"height\": 0.26,\n \"on\": \"lamp\"\n }\n ]\n}", "exit_code": 0, "status": "completed"}}
{"type": "item.started", "item": {"id": "item_3", "type": "command_execution", "command": "/bin/bash -lc \"cat > solve.py <<'PY'\nimport json\nimport math\nimport sys\n\n\ndef bounds(vertices):\n return [[min(v[k] for v in vertices) for k in range(3)],\n [max(v[k] for v in vertices) for k in range(3)]]\n\n\ndef mesh(part, cx, bottom, cz, segments):\n shape = part['shape']\n vertices, polygons = [], []\n if shape == 'box':\n sx, height, sz = part['size']\n for y in (bottom, bottom + height):\n vertices.extend([(cx - sx / 2, y, cz - sz / 2),\n (cx + sx / 2, y, cz - sz / 2),\n (cx + sx / 2, y, cz + sz / 2),\n (cx - sx / 2, y, cz + sz / 2)])\n polygons = [[0, 1, 2, 3], [4, 5, 6, 7]]\n polygons += [[i, (i + 1) % 4, (i + 1) % 4 + 4, i + 4]\n for i in range(4)]\n else:\n height = part['height']\n if shape == 'frustum':\n rb, rt = part['radius_bottom'], part['radius_top']\n elif shape == 'cone':\n rb, rt = part['radius'], 0\n elif shape == 'cylinder':\n rb = rt = part['radius']\n else:\n raise ValueError('Unsupported shape: ' + shape)\n rings = []\n for radius, y in ((rb, bottom), (rt, bottom + height)):\n start = len(vertices)\n if radius == 0:\n vertices.append((cx, y, cz))\n rings.append([start])\n else:\n for i in range(segments):\n # Exact cardinal points preserve the ideal bounding box.\n if i % (segments // 4) == 0:\n x, z = ((1, 0), (0, 1), (-1, 0), (0, -1))[i // (segments // 4)]\n else:\n angle = 2 * math.pi * i / segments\n x, z = math.cos(angle), math.sin(angle)\n vertices.append((cx + radius * x, y, cz + radius * z))\n rings.append(list(range(start, start + segments)))\n lower, upper = rings\n if len(lower) > 1:\n polygons.append(lower)\n if len(upper) > 1:\n polygons.append(upper)\n for i in range(segments):\n j = (i + 1) % segments\n if len(upper) == 1:\n polygons.append([lower[i], upper[0], lower[j]])\n elif len(lower) == 1:\n polygons.append([lower[0], upper[i], upper[j]])\n else:\n polygons.append([lower[i], upper[i], upper[j], lower[j]])\n interior = (cx, bottom + height / 2, cz)\n triangles = []\n for polygon in polygons:\n a, b, c = [vertices[i] for i in polygon[:3]]\n u = [b[k] - a[k] for k in range(3)]\n v = [c[k] - a[k] for k in range(3)]\n normal = (u[1]*v[2]-u[2]*v[1], u[2]*v[0]-u[0]*v[2], u[0]*v[1]-u[1]*v[0])\n if sum(normal[k] * (a[k] - interior[k]) for k in range(3)) < 0:\n polygon = list(reversed(polygon))\n triangles.extend((polygon[0], polygon[i], polygon[i + 1])\n for i in range(1, len(polygon) - 1))\n return vertices, triangles\n\n\ndef main():\n with open('asset.json') as handle:\n brief = json.load(handle)\n segments = max(4, 4 * math.ceil(brief['min_segments'] / 4))\n definitions = {p['name']: p for p in brief['parts']}\n resolved, active, objects = {}, set(), {}\n\n def resolve(name):\n if name in resolved:\n return resolved[name]\n if name in active:\n raise ValueError('Cyclic part placement')\n active.add(name)\n part = definitions[name]\n parent = part.get('on', 'ground')\n if parent == 'ground':\n parent_bounds = [[0, 0, 0], [0, 0, 0]]\n else:\n parent_bounds = resolve(parent)\n lo, hi = parent_bounds\n dx, dz = part.get('offset', [0, 0])\n centers = [((lo[0] + hi[0]) / 2 + dx, (lo[2] + hi[2]) / 2 + dz)]\n array = part.get('array')\n if array:\n if array['layout'] \"'!= '\"'corners' or array['count'] \"'!= 4:\n raise ValueError('\"'Unsupported array')\n s = array['inset']\n centers = [(lo[0]+s+dx, lo[2]+s+dz), (hi[0]-s+dx, lo[2]+s+dz),\n (hi[0]-s+dx, hi[2]-s+dz), (lo[0]+s+dx, hi[2]-s+dz)]\n all_vertices = []\n for i, (cx, cz) in enumerate(centers):\n object_name = name + '.' + str(i + 1) if array else name\n vertices, triangles = mesh(part, cx, hi[1], cz, segments)\n objects[object_name] = (vertices, triangles)\n all_vertices.extend(vertices)\n resolved[name] = bounds(all_vertices)\n active.remove(name)\n return resolved[name]\n\n for part in brief['parts']:\n resolve(part['name'])\n total = sum(len(t) for v, t in objects.values())\n if total > brief['triangle_budget']:\n raise ValueError('Triangle budget is below the minimum required by the brief')\n answer = {'triangles': total, 'parts': {}}\n with open('asset.obj', 'w') as handle:\n index = 1\n for name, (vertices, triangles) in objects.items():\n handle.write('o ' + name + '\\\\n')\n for vertex in vertices:\n handle.write('v ' + ' '.join(format(x, '.17g') for x in vertex) + '\\\\n')\n for triangle in triangles:\n handle.write('f ' + ' '.join(str(i + index) for i in triangle) + '\\\\n')\n index += len(vertices)\n answer['parts'][name] = {'triangles': len(triangles), 'bounds': bounds(vertices)}\n with open(sys.argv[2], 'w') as handle:\n json.dump(answer, handle, indent=2)\n handle.write('\\\\n')\n\n\nif __name__ == '__main__':\n main()\nPY\npython solve.py input.json answer.json\"", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_3", "type": "command_execution", "command": "/bin/bash -lc \"cat > solve.py <<'PY'\nimport json\nimport math\nimport sys\n\n\ndef bounds(vertices):\n return [[min(v[k] for v in vertices) for k in range(3)],\n [max(v[k] for v in vertices) for k in range(3)]]\n\n\ndef mesh(part, cx, bottom, cz, segments):\n shape = part['shape']\n vertices, polygons = [], []\n if shape == 'box':\n sx, height, sz = part['size']\n for y in (bottom, bottom + height):\n vertices.extend([(cx - sx / 2, y, cz - sz / 2),\n (cx + sx / 2, y, cz - sz / 2),\n (cx + sx / 2, y, cz + sz / 2),\n (cx - sx / 2, y, cz + sz / 2)])\n polygons = [[0, 1, 2, 3], [4, 5, 6, 7]]\n polygons += [[i, (i + 1) % 4, (i + 1) % 4 + 4, i + 4]\n for i in range(4)]\n else:\n height = part['height']\n if shape == 'frustum':\n rb, rt = part['radius_bottom'], part['radius_top']\n elif shape == 'cone':\n rb, rt = part['radius'], 0\n elif shape == 'cylinder':\n rb = rt = part['radius']\n else:\n raise ValueError('Unsupported shape: ' + shape)\n rings = []\n for radius, y in ((rb, bottom), (rt, bottom + height)):\n start = len(vertices)\n if radius == 0:\n vertices.append((cx, y, cz))\n rings.append([start])\n else:\n for i in range(segments):\n # Exact cardinal points preserve the ideal bounding box.\n if i % (segments // 4) == 0:\n x, z = ((1, 0), (0, 1), (-1, 0), (0, -1))[i // (segments // 4)]\n else:\n angle = 2 * math.pi * i / segments\n x, z = math.cos(angle), math.sin(angle)\n vertices.append((cx + radius * x, y, cz + radius * z))\n rings.append(list(range(start, start + segments)))\n lower, upper = rings\n if len(lower) > 1:\n polygons.append(lower)\n if len(upper) > 1:\n polygons.append(upper)\n for i in range(segments):\n j = (i + 1) % segments\n if len(upper) == 1:\n polygons.append([lower[i], upper[0], lower[j]])\n elif len(lower) == 1:\n polygons.append([lower[0], upper[i], upper[j]])\n else:\n polygons.append([lower[i], upper[i], upper[j], lower[j]])\n interior = (cx, bottom + height / 2, cz)\n triangles = []\n for polygon in polygons:\n a, b, c = [vertices[i] for i in polygon[:3]]\n u = [b[k] - a[k] for k in range(3)]\n v = [c[k] - a[k] for k in range(3)]\n normal = (u[1]*v[2]-u[2]*v[1], u[2]*v[0]-u[0]*v[2], u[0]*v[1]-u[1]*v[0])\n if sum(normal[k] * (a[k] - interior[k]) for k in range(3)) < 0:\n polygon = list(reversed(polygon))\n triangles.extend((polygon[0], polygon[i], polygon[i + 1])\n for i in range(1, len(polygon) - 1))\n return vertices, triangles\n\n\ndef main():\n with open('asset.json') as handle:\n brief = json.load(handle)\n segments = max(4, 4 * math.ceil(brief['min_segments'] / 4))\n definitions = {p['name']: p for p in brief['parts']}\n resolved, active, objects = {}, set(), {}\n\n def resolve(name):\n if name in resolved:\n return resolved[name]\n if name in active:\n raise ValueError('Cyclic part placement')\n active.add(name)\n part = definitions[name]\n parent = part.get('on', 'ground')\n if parent == 'ground':\n parent_bounds = [[0, 0, 0], [0, 0, 0]]\n else:\n parent_bounds = resolve(parent)\n lo, hi = parent_bounds\n dx, dz = part.get('offset', [0, 0])\n centers = [((lo[0] + hi[0]) / 2 + dx, (lo[2] + hi[2]) / 2 + dz)]\n array = part.get('array')\n if array:\n if array['layout'] \"'!= '\"'corners' or array['count'] \"'!= 4:\n raise ValueError('\"'Unsupported array')\n s = array['inset']\n centers = [(lo[0]+s+dx, lo[2]+s+dz), (hi[0]-s+dx, lo[2]+s+dz),\n (hi[0]-s+dx, hi[2]-s+dz), (lo[0]+s+dx, hi[2]-s+dz)]\n all_vertices = []\n for i, (cx, cz) in enumerate(centers):\n object_name = name + '.' + str(i + 1) if array else name\n vertices, triangles = mesh(part, cx, hi[1], cz, segments)\n objects[object_name] = (vertices, triangles)\n all_vertices.extend(vertices)\n resolved[name] = bounds(all_vertices)\n active.remove(name)\n return resolved[name]\n\n for part in brief['parts']:\n resolve(part['name'])\n total = sum(len(t) for v, t in objects.values())\n if total > brief['triangle_budget']:\n raise ValueError('Triangle budget is below the minimum required by the brief')\n answer = {'triangles': total, 'parts': {}}\n with open('asset.obj', 'w') as handle:\n index = 1\n for name, (vertices, triangles) in objects.items():\n handle.write('o ' + name + '\\\\n')\n for vertex in vertices:\n handle.write('v ' + ' '.join(format(x, '.17g') for x in vertex) + '\\\\n')\n for triangle in triangles:\n handle.write('f ' + ' '.join(str(i + index) for i in triangle) + '\\\\n')\n index += len(vertices)\n answer['parts'][name] = {'triangles': len(triangles), 'bounds': bounds(vertices)}\n with open(sys.argv[2], 'w') as handle:\n json.dump(answer, handle, indent=2)\n handle.write('\\\\n')\n\n\nif __name__ == '__main__':\n main()\nPY\npython solve.py input.json answer.json\"", "aggregated_output": "/bin/bash: line 141: python: command not found\n", "exit_code": 127, "status": "failed"}}
{"type": "item.started", "item": {"id": "item_4", "type": "command_execution", "command": "/bin/bash -lc \"python3 solve.py input.json answer.json\npython3 - <<'PY'\nimport solve, collections, json\nbrief=json.load(open('asset.json'))\nfor shape in [dict(shape='box',size=[1,2,3]),dict(shape='cylinder',radius=1,height=2),dict(shape='cone',radius=1,height=2),dict(shape='frustum',radius_bottom=1,radius_top=.5,height=2)]:\n v,t=solve.mesh(shape,.4,1,.7,12)\n edges=collections.defaultdict(list)\n volume=0\n for tri in t:\n a,b,c=[v[i] for i in tri]\n cross=(b[1]*c[2]-b[2]*c[1],b[2]*c[0]-b[0]*c[2],b[0]*c[1]-b[1]*c[0])\n volume+=sum(a[k]*cross[k] for k in range(3))/6\n for i,j in zip(tri,tri[1:]+tri[:1]):\n edges[tuple(sorted((i,j)))].append((i,j))\n assert all(len(e)==2 and e[0]==e[1][::-1] for e in edges.values())\n assert volume>0\n print(shape['shape'],len(t),'triangles; manifold, consistent winding, positive volume')\nprint('Asset triangles:', json.load(open('answer.json'))['triangles'])\nPY\"", "aggregated_output": "", "exit_code": null, "status": "in_progress"}}
{"type": "item.completed", "item": {"id": "item_4", "type": "command_execution", "command": "/bin/bash -lc \"python3 solve.py input.json answer.json\npython3 - <<'PY'\nimport solve, collections, json\nbrief=json.load(open('asset.json'))\nfor shape in [dict(shape='box',size=[1,2,3]),dict(shape='cylinder',radius=1,height=2),dict(shape='cone',radius=1,height=2),dict(shape='frustum',radius_bottom=1,radius_top=.5,height=2)]:\n v,t=solve.mesh(shape,.4,1,.7,12)\n edges=collections.defaultdict(list)\n volume=0\n for tri in t:\n a,b,c=[v[i] for i in tri]\n cross=(b[1]*c[2]-b[2]*c[1],b[2]*c[0]-b[0]*c[2],b[0]*c[1]-b[1]*c[0])\n volume+=sum(a[k]*cross[k] for k in range(3))/6\n for i,j in zip(tri,tri[1:]+tri[:1]):\n edges[tuple(sorted((i,j)))].append((i,j))\n assert all(len(e)==2 and e[0]==e[1][::-1] for e in edges.values())\n assert volume>0\n print(shape['shape'],len(t),'triangles; manifold, consistent winding, positive volume')\nprint('Asset triangles:', json.load(open('answer.json'))['triangles'])\nPY\"", "aggregated_output": "box 12 triangles; manifold, consistent winding, positive volume\ncylinder 44 triangles; manifold, consistent winding, positive volume\ncone 22 triangles; manifold, consistent winding, positive volume\nfrustum 44 triangles; manifold, consistent winding, positive volume\nAsset triangles: 90\n", "exit_code": 0, "status": "completed"}}
{"type": "item.completed", "item": {"id": "item_5", "type": "agent_message", "text": "Created [solve.py](solve.py), which reads `asset.json` and generates `asset.obj` and `answer.json`.\n\nThe supplied asset uses **90 of 92 triangles**. Verified all four shape types for closed manifold edges, consistent winding, and positive volume.\n\nRan with `python3`; this environment has no `python` alias."}}
{"type": "turn.completed", "usage": {"input_tokens": 69971, "cached_input_tokens": 65152, "cache_write_input_tokens": 0, "output_tokens": 2501, "reasoning_output_tokens": 205}}