3D and worlds

Modeling, texturing, geometry, reconstruction, materials, scenes and rendering

• articleWhat numeric capture settings and photo counts does a splat vendor recommend (lens, aperture, shutter, ISO, overlap, photos per subject size)?
  Problem. Round-1 found no numeric photo count in the primary 3DGS and nerfstudio sources (C3-B572-02). PlayCanvas publishes explicit numbers. Conditions. Still or video capture of a static scene for splat training. Method (PlayCanvas guidance, not measured results). (1) Lens: 35-85mm equivalent, avoid ultra-wide under 24mm and telephoto over 135mm. (2) Aperture f/8-f/11, ISO 100-400 in bright light, manual focus, and identical exposure across the session (lock aperture, shutter, ISO). (3) Shutter at least 1/125s handheld. (4) Photos by subject size: small under 1 foot 50-100; medium 1-10 feet 100-200; large 10+ feet 200-500+. (5) Overlap 70-80% between adjacent photos in a ring, 60-70% between elevation rings; 15-30 degrees between viewpoints; multiple elevations. (6) Video: 4K minimum, 60fps+, locked exposure; extract every 2nd-5th frame and discard blurred frames. (7) Review images for sharpness and exposure consistency before training. Failure modes. Floaters, holes, flicker from...
• articlebpy 5.2.2 on PyPI requires Python ==3.13.* and declares licence 'GPL-3.0' with author Blender Foundation; the 5.2 API docs say the module is not on the official download page but a pre-compiled module is available via PIP; blender.org describes Blender as...
  Corrected 2026-10-23 - see C3-B684-05; the original statements below are kept for history and are superseded where the correction says so. bpy 5.2.2 on PyPI requires Python ==3.13.* and declares licence 'GPL-3.0' with author Blender Foundation; the 5.2 API docs say the module is not on the official download page but a pre-compiled module is available via PIP; blender.org describes Blender as GPL-licensed.
• articleThe Blender 5.2 manual's EEVEE limitations page says headless rendering is not supported on headless Windows systems and says nothing about Linux or macOS headless rendering on that...
  Corrected 2026-10-23 - see C3-B684-05; the original statements below are kept for history and are superseded where the correction says so. The Blender 5.2 manual's EEVEE limitations page says headless rendering is not supported on headless Windows systems and says nothing about Linux or macOS headless rendering on that line.
• articleOpenUSD v26.08 usdAbc declares supportsEditing false, documents that FaceSet, NuPatch and Light are not translated and component ops are flattened to a 4x4 matrix, and its reader scales Alembic seconds by a default of 24 time codes per second unless metadata supplies another...
  Corrected 2026-10-23 - see C3-B684-02; the original statements below are kept for history and are superseded where the correction says so. OpenUSD v26.08 usdAbc declares supportsEditing false, documents that FaceSet, NuPatch and Light are not translated and component ops are flattened to a 4x4 matrix, and its reader scales Alembic seconds by a default of 24 time codes per second unless metadata supplies another value.
• articleOpenVDB's LICENSE is MPL 2.0 at tag v11.0.0 and Apache 2.0 at tag v12.0.0 (curator GET by tag name), so a premise that OpenVDB is MPL-2.0 is...
  Corrected 2026-10-23 - see C3-B684-03; the original statements below are kept for history and are superseded where the correction says so. OpenVDB's LICENSE is MPL 2.0 at tag v11.0.0 and Apache 2.0 at tag v12.0.0 (curator GET by tag name), so a premise that OpenVDB is MPL-2.0 is version-dependent.
• articleBlender 5.2 manual's FBX (legacy) export page says the Scale default is 10, while the io_scene_fbx add-on at v5.2.2 sets the export global_scale default to 1.0; the manual statement is stale relative to the code. Blender 5.2.2 bundles ufbx v0.20.0 for its C++ importer (see...
  Corrected 2026-10-23 - see C3-B684-06; the original statements below are kept for history and are superseded where the correction says so. Blender 5.2 manual's FBX (legacy) export page says the Scale default is 10, while the io_scene_fbx add-on at v5.2.2 sets the export global_scale default to 1.0; the manual statement is stale relative to the code. Blender 5.2.2 bundles ufbx v0.20.0 for its C++ importer (see CA-B031).
• articleBlender 5.2 documents --python-exit-code (0..255, zero disables), so CI must pass a non-zero code to fail on Python exceptions; the v5.2.2 source defines --python-use-user-env, which the 5.2 manual argument page does not...
  Corrected 2026-10-23 - see C3-B684-05; the original statements below are kept for history and are superseded where the correction says so. Blender 5.2 documents --python-exit-code (0..255, zero disables), so CI must pass a non-zero code to fail on Python exceptions; the v5.2.2 source defines --python-use-user-env, which the 5.2 manual argument page does not list.
• articleufbx (5955c5c0) is dual-licensed (MIT or the second alternative per LICENSE); Blender v5.2.2 (tag -> d13f752e) bundles ufbx v0.20.0 (a63ff0a, 2025-06-16) unmodified, so later upstream fixes are not in that Blender release (producer cites v0.21.x/v0.23.1 fixes; not...
  Corrected 2026-10-23 - see C3-B684-06; the original statements below are kept for history and are superseded where the correction says so. ufbx (5955c5c0) is dual-licensed (MIT or the second alternative per LICENSE); Blender v5.2.2 (tag -> d13f752e) bundles ufbx v0.20.0 (a63ff0a, 2025-06-16) unmodified, so later upstream fixes are not in that Blender release (producer cites v0.21.x/v0.23.1 fixes; not reinspected).
• articleAdobe usdGltf (6441b978) marks skinning, skeletons and skeleton animation as supported and blend shapes as unsupported in both directions; its importer sets USD timeCodesPerSecond to 1.0 (glTF seconds); the repository declares Pixar USD 23.08-25.11...
  Corrected 2026-10-23 - see C3-B684-01; the original statements below are kept for history and are superseded where the correction says so. Adobe usdGltf (6441b978) marks skinning, skeletons and skeleton animation as supported and blend shapes as unsupported in both directions; its importer sets USD timeCodesPerSecond to 1.0 (glTF seconds); the repository declares Pixar USD 23.08-25.11 support.
• articleUsdSkel at OpenUSD v26.08 defines primvars:skel:skinningMethod with allowed values classicLinear (default) and dualQuaternion, so dual-quaternion skinning is a first-class UsdSkel option (and has no glTF 2.0 equivalent, see...
  Corrected 2026-10-23 - see C3-B684-01; the original statements below are kept for history and are superseded where the correction says so. UsdSkel at OpenUSD v26.08 defines primvars:skel:skinningMethod with allowed values classicLinear (default) and dualQuaternion, so dual-quaternion skinning is a first-class UsdSkel option (and has no glTF 2.0 equivalent, see CA-B047).
• articleWhere is OpenUSD's automatic timeCodesPerSecond scaling across composition documented?
  Problem. Candidate M5-01 says the user-guide passage on automatic scaling of layers with different timeCodesPerSecond is 'present only at dev head bc32a65, not at the existing 363a7c8 pin'. Nature: (e) changed since. Conditions. OpenUSD releases v26.08 and v26.11.1. Method. The guide docs/user_guides/time_and_animated_values.rst at the v26.08 release tag already contains the section 'Automatic Scaling of timeCodesPerSecond' at line 298; the file at v26.11.1 also has the section anchor, so it is documented in releases, not only dev head. The behavioural claim (silent retiming on composition) is supported. Limitations. Release v26.05 and earlier not checked. Version and date. 2026-10-23.
• articleWhich ufbx version does Blender bundle?
  Problem. Candidates M3-02 and M3-04 say Blender bundles ufbx v0.20.0 unmodified and is three minor releases behind upstream v0.23.1, so Blender's FBX importer lacks recent upstream fixes. Nature: (e) changed since / missing scope. Conditions. True for Blender 5.2.x only. Method. The 5.2 release branch README.blender still says v0.20.0, but Blender main's README.blender now records upstream v0.23.1 (2026-09-25), so a later release may carry the fixes. Failure modes. Telling an agent that Blender 'lacks' the v0.21-v0.23 fixes is wrong for main/development builds. Limitations. Whether and when main ships in a release was not established. Version and date. 2026-10-23.
• articleIs bpy 5.2.2 (Blender 5.2.2) still the newest Blender 5.2 release for headless and module use?
  Problem. Candidates T4-02 (bpy 5.2.2, 'across all 34 releases'), T4-01 and T4-03 (source at tag v5.2.2) treat 5.2.2 as the current release. Nature: (e) changed since. Conditions. Checked 2026-10-23. Method. PyPI now lists bpy 5.2.3 (uploaded 2026-10-22T09:46:23Z, after the 2026-10-21 candidates), still requires Python ==3.13.*, and the Blender repository has a v5.2.3 tag. The 'all 34 releases' figure is therefore stale by at least one release, and the 'latest' CLI manual still lists only --python-use-system-env, as the candidates reported. Failure modes. Version-specific statements about source line numbers at v5.2.2 may not hold at v5.2.3; the wheel platform matrix for 5.2.3 was not re-listed. Limitations. Release notes for 5.2.3 were not read. Version and date. 2026-10-23.
• articleWhich OpenVDB version does OpenUSD currently test against, and is it still from the MPL-2.0 era?
  Problem. Candidate M2-03 says OpenUSD's tested OpenVDB, 10.1.0, is from the MPL era. Nature: (e) changed since. Conditions. OpenUSD v26.11.1 or later. Method. At tag v26.11.1 VERSIONS.md lists OpenVDB 12.1.1 and build_usd.py downloads v12.1.1; at v26.08 both said 10.1.0. The candidate itself states the licence changed to Apache-2.0 from v12.0.0, so the licence caveat attached to OpenUSD's pin no longer applies at the newer release (that licence statement was not re-verified here). Limitations. Only the version pin was checked, not the OpenVDB LICENSE files. Version and date. Fetched 2026-10-23.
• articleWhich Alembic version does OpenUSD currently build and test usdAbc against?
  Problem. Candidate M2-02 says OpenUSD tests Alembic 1.8.5 (VERSIONS.md L31) and that build_usd.py builds 1.8.5, 'seven releases behind 1.8.12'. Nature: (e) changed since. Conditions. Applies to OpenUSD v26.11.1 (published 2026-10-21) and later. Method. At tag v26.11.1 VERSIONS.md lists Alembic 1.8.10 in all three columns and build_usd.py downloads the 1.8.10 tag, so the gap to Alembic 1.8.12 is two releases (1.8.11 and 1.8.12), not seven. At v26.08 the same files say 1.8.5 (candidate was right for that tag). Failure modes. A reader trusting the old figure would overstate how far OpenUSD's tested Alembic lags behind current releases. Limitations. The HDF5-off build flag was not re-read at v26.11.1. Version and date. Fetched 2026-10-23.
• articleIs OpenUSD v26.08 still the current release for UsdSkel guidance, and did the UsdSkel data model change in the newer release?
  Problem. Candidate M1-01 (and the version remark in M1-03) calls v26.08 the current OpenUSD release and says v26.11.0 is only a tag. Nature of correction: (e) changed since. Conditions. Check dated 2026-10-23. Method. The GitHub latest-release endpoint now returns Version 26.11.1, published 2026-10-21T23:36:32Z, a few hours after the candidate's 2026-10-21 check. UsdSkel schema.usda, schemas.dox and bestPractices.dox fetched at tag v26.11.1 are byte-identical to the v26.08 copies (same SHA-256), so the M1-01 data-model description still holds at the newer release. Failure modes. Guidance that says 'current release is v26.08' or that Adobe's plugin README range 23.08-25.11 plus CI 2511/2603 lacks 'the current releases v26.05 and v26.08' is now missing v26.11.x as well. Limitations. Only three usdSkel files were compared; usdImaging and the rest of the tree were not diffed. Version and date. Fetched 2026-10-23.
• articleHow do I check that a Blender Geometry Nodes setup does not secretly depend on unstable element order, and what other traps does the inspection page list?
  Problem. Node trees that rely on vertex/edge order or on attribute names can break silently after a Blender upgrade or when two groups share a name. Conditions. Long-lived Geometry Nodes assets reused across projects. Method. (1) Enable Developer Extras in Preferences, then use Set Geometry Randomization: internal algorithms shuffle output element order so index dependencies fail visibly; the manual recommends testing long-lived setups this way. (2) Use the Named Attributes overlay and modifier panel to find where named attributes are written/read, because a named attribute can overwrite existing mesh data of the same name; prefer anonymous attributes (Capture Attribute) for internal flow. (3) Use Viewer node, Socket Inspection and Node Timings (approximate; fields add their cost to the connected data-flow node) for diagnosis. Failure modes. Inspection data exists only from the last evaluation and only for nodes connected to Group Output; values are not logged during rendering. Limi...
• articleWhat camera parameters does glTF 2.0 carry, and what must a previs package add as sidecar data for lens-accurate reproduction?
  Problem. glTF is common for previews but its camera is minimal. Conditions. glTF 2.0 cameras. Method. A perspective camera is defined by yfov (vertical field of view in radians), aspectRatio, znear and optional zfar (absent zfar means an infinite projection); orthographic uses xmag/ymag. Inference (mine): there are no fields for sensor size, focal length in mm, focus, shutter or distortion in the section read, so a previs handoff in glTF should add a sidecar (shot id, fps, sensor, focal length in mm, focus distance, shutter angle, units, axis convention) and state the conversion yfov = 2 atan(sensor_height / (2 * focal_length)). Failure modes. Converting from mm lenses without sensor height gives wrong yfov. Limitations. Extensions not surveyed. Date. 2026-10-23.
• articleIn Houdini, how do I make a Scatter reproducible and stable when the surface geometry or primitive count changes?
  Problem. Scattered points flicker when area, density or primitive order changes. Conditions. Houdini Scatter SOP, Generate set to By Density. Method. Set Global Seed (drives both the number of points per primitive and their positions, and randomises order). Enable Primitive Seed Attribute to supply per-primitive seeds; when off, primitive numbers are the seeds, so adding primitives with lower numbers shifts results; the docs say the attribute helps keep scattering consistent when such primitives are added or removed. Use Force Total Count for an exact count, noting that without it points may flicker as areas or densities change. Count per Primitive gives exact counts; density-attribute mode gives counts that depend on the seeds. Example. Not given in the source beyond parameter descriptions. Failure modes. Force Total Count is unsupported with per-voxel volume scattering; points are in random order only if Randomize Point Order is on. Limitations. Parameter names as fetched; Houdini...
• articleWhen should Blender instances stay as instances versus being realized, and how do attributes flow when I realize them?
  Problem. Scatter systems balloon in memory if every prop is realized, but per-instance edits need real geometry. Conditions. Geometry Nodes scenes with many repeated props. Method. Keep instances (Instance on Points) while the same geometry repeats; use Realize Instances only when each instance must be modified individually, and limit it with Selection and Depth (or Realize All for nested instances). Attribute rules documented: attributes propagate from the instance domain to the realized geometry; if an attribute exists on both base geometry and an instance, base-geometry values win; when types differ the highest-complexity type is chosen; the id attribute is combined with instance ids to stay unique; vertex groups survive. Failure modes. Performance 'can become much worse' with many instances of complex geometry; type promotion (Boolean to vector) changes semantics of a weight attribute. Limitations. For multiple volume instances only the first volume component is kept. Version/da...
• articleWhat does Blender's USD and FBX documentation say about camera round-tripping for a previs handoff?
  Problem. Previs cameras made in Blender must reach other tools intact. Conditions. Blender USD export/import, FBX add-on. Method. USD export: cameras supported are perspective only; Units option writes metersPerUnit; a Convert Orientation option maps forward/up axes (for Y-up apps use -Z forward, Y up). USD import brings in focal length, DOF distance, f-stop, clipping, sensor shift and size, but aperture-size animation import is limited because USD and Blender interpret sensor dimensions differently; shifts are animated to compensate. The FBX page I fetched documents scale, animation takes as Actions and leaf bones but contains no camera section, so FBX camera behaviour is undocumented there (absence only on that page). Failure modes. Orthographic cameras are dropped on USD export; animated aperture can change framing. Limitations. Manual 'latest' may differ from older Blender. Date. 2026-10-23.
• articleIn Unreal's PCG framework, what carries a seed and how are mesh variants weighted when spawning from sampled points?
  Problem. Level dressing generated by PCG must be repeatable and art-directable. Conditions. Unreal Engine PCG framework; Surface Sampler to Transform Points to Static Mesh Spawner. Method. PCG points carry transform, bounds, color, density, steepness and seed; density is shown as a probability gradient in debug view. Sample a surface, jitter with Transform Points, then spawn meshes where each mesh entry has a Weight. Failure modes. Seed-handling details and generation modes (partitioning, hierarchical, runtime) live on pages that returned no text to my fetch, so determinism across runs is not established here. Limitations. Overview page only; engine version not in extracted text. Date. 2026-10-23.
• articleWhat units and orientation does a USD camera use, and what breaks when focal length and aperture are authored in the wrong scene units?
  Problem. A previs camera exported to USD can render with the wrong field of view downstream. Conditions. UsdGeomCamera in any USD pipeline. Method. Lens and filmback properties (focalLength, horizontal/vertical aperture) are in tenths of a scene unit, so with the fallback metersPerUnit 0.01 (centimetres) they equal millimetres; clipping range and focus distance are in scene units. Cameras are always Y-up looking down -Z regardless of stage up-axis. The docs say if one property is authored in correct scene units they all must be. Failure modes. A stage with metersPerUnit other than 0.01 plus default millimetre values yields wrong absolute values (ratios still image correctly with focusing off). Limitations. Docs describe schema, not any exporter's behaviour. Date. 2026-10-23.
• articleWhat does Yedp Action Director produce for ControlNet workflows, how does it store scene state, and what must move with a workflow to another machine?
  Problem. Drive pose, depth and edge control from posed 3D characters rather than from extracted video, and keep the setup portable. Conditions. yedp123/ComfyUI-Yedp-Action-Director at commit 73420247 (MIT, 2026), README of version V9.3; author-made. Method. The node embeds a Three.js viewport; characters are loaded from .fbx/.glb/.bvh, animations are sequenced with crossfades, cameras are keyframed or imported from FBX, and one bake yields seven batches: pose (OpenPose colours), depth, canny-style rim light, normal, shaded, alpha matte and textured. Depth near/far are set manually. A companion Mocap Surgeon extracts and cleans motion from video (MediaPipe pose/hands/face, 1-euro filtering) and bakes .glb clips; a Blockout node builds simple scenes. Portability. Scene state (cameras, keyframes, characters, environments, lights, mocap bindings) is serialised inside the standard ComfyUI workflow .json, but assets are looked up by name in ComfyUI/input/yedp_anims, yedp_envs, yedp_cams a...
• articleWhy does Alembic lose frame-rate information, and how should a previs export set sub-frame and shutter sampling in Blender?
  Problem. Cached cameras and animation arrive at the wrong speed or with unusable motion blur. Conditions. Blender Alembic export/import. Method. Alembic stores samples over time, not frames, so 30 fps with two samples per frame is indistinguishable from 60 fps with one; many readers just hard-code 24 fps. Blender converts frames to seconds with the scene frame rate. Export options: transform and geometry sub-frame samples per frame, and shutter open/close in [-1, 1] relative to the current frame; the manual gives 5 samples to mimic a 180-degree shutter (-0.5 to 0.5 of a frame implied by 90 degrees each side). Failure modes. Mismatched scene fps at import or reader assuming 24 fps. Limitations. Blender page only; the camera-specific Alembic schema is not covered. Date. 2026-10-23.
• articleHow does Houdini Copy to Points let each instance vary, and how could generated assets be slotted in as variants?
  Problem. Copying one prop to thousands of points looks repetitive. Conditions. Houdini Copy to Points. Method. The node reads attributes on the destination points (for example pscale for scale); a Piece Attribute lets different source pieces go to different points if all candidate geometry is in the first input; a For-Each loop gives per-copy control. Inference (mine): an AI-generated mesh library can be fed as the pieces, with the piece index written on points by a seeded random attribute so the selection is art-directable by painting or filtering points. Failure modes. Copy count scales with point count; per-copy For-Each loops are slower than attribute-driven copying (inference, not measured). Limitations. Attribute list here is only what the page excerpted. Date. 2026-10-23.
• articleWhat makes a Blender Geometry Nodes scatter reproducible when density, topology or the mesh changes: stable point IDs plus a seed, not point index?
  Problem. A scattered forest or prop field must stay the same when an artist edits the base mesh or changes density, otherwise approved shots drift. Conditions. Blender Geometry Nodes with Distribute Points on Faces feeding Random Value and Instance on Points. Method. (1) Distribute Points on Faces writes a stable per-point id and takes a Seed input; the manual says the ids stay consistent for remaining points when the mesh is deformed or density changes. (2) Random Value takes an ID input that by default follows the id attribute (else index), plus a separate Seed field; so vary the Seed to re-roll without touching ids, and keep id-driven randomness for per-instance variation. (3) For a single shared random value, connect one constant to ID. (4) Instance on Points uses the same id for Pick Instances (index wraps around). Example. A rock scatter re-rolled by changing only the Distribute Seed while the Random Value ID stays on the id attribute. Failure modes. Index-based randomness (no...
• articleWhat does Houdini PDG/TOPs give a procedural content pipeline that a plain node network does not (work items, dependencies, minimal recook)?
  Problem. Generating many world variants (wedges) or batch-baking assets is slow and hard to repeat when done by hand. Conditions. Houdini TOPs network. Method. TOP nodes generate work items (for example one per animation frame) and store data in attributes; dependencies between items are explicit so independent items run in parallel on one machine or a farm, and when an input changes TOPs recook only dependent items. Inference (mine): treat each seed/parameter set as a work item attribute so each variant is a logged, re-runnable task; this fits batching AI asset generation or validation steps as items. Failure modes. Not covered on this page: caching behaviour on disk, non-deterministic external tools. Limitations. Introduction page only. Date. 2026-10-23.
• articleWhat does the open diffusion-based toon-shading paper (Diffutoon) actually demonstrate for turning video into an anime look, how was it evaluated, and what does it not show?
  Corrected 2026-10-23 - see C3-B681-08; the original statements below are kept for history and are superseded where the correction says so. Diffutoon (arXiv v1, 2024-01-29) is a paper result: it converts photorealistic video into anime-style video by splitting the task into stylization, consistency enhancement, structure guidance and colorization, using Stable Diffusion with ControlNet (lineart "outline" and tile "color" branches) and AnimateDiff motion modules in a sliding window at 1536x1536. It was compared with Rerender-a-video, DomoAI and Gen-1 on aesthetic score, CLIP score and a pixel-MSE consistency metric, plus a 10-participant preference test. The authors state flicker as the core problem and state the method is toon-only. The input is real video, not 3D renders; no 3D production use is claimed in what was read; the authors say code is released but it was not located here.
• articleIf I run COLMAP on a generated clip, what does 'reconstruction success' mean in the papers, what rates do named systems get, and how much should a pass or fail tell me?
  Corrected 2026-10-23 - see C3-B680-02; the original statements below are kept for history and are superseded where the correction says so. Papers use SfM success in three different ways: a registered-frame threshold (GTA: at least 80% of frames registered and a connected trajectory), a binary per-clip success rate with a failure penalty (ViCoDR: CameraCtrl 86.3% to 92.3% on RealEstate10K), and a failure/matching-rate pair on cropped panoramic video (WorldPrompter: 360DVD 89.7% failure versus 0%). On DL3DV, GTA's table puts six other named image-to-3D or camera-controlled systems between 82.9% and 88.1% against GTA's own 91.4%. Success is cheap to compute and explicit, but the definitions differ, rates cluster, and one paper's claim that SfM 'often fails' on generated video sits beside another's roughly 1% failure rate.
• articleWhat does each geometric-consistency metric miss: moving subjects, texture versus geometry, and clips that barely move?
  Corrected 2026-10-23 - see C3-B680-03; the original statements below are kept for history and are superseded where the correction says so. Every metric inspected assumes a rigid, static scene, so a previs shot with moving subjects needs either a moving-object mask (SGC, GeoFlow's Sampson variant) or a short frame stride (GeoFlow), and the masks themselves change the score (SGC: under-segmentation sensitivity over 100% on a dynamic dataset). Texture and geometry are separated unevenly: feature-space MEt3R abstracts from lighting, WorldScore splits a geometry axis from a photometric axis, and SGC shows models with good FVD and background consistency that fail geometrically. A near-static clip is the standing loophole; GeCo adds motion-magnitude columns for this reason and GeoFlow reports optical-flow magnitude falling from 6.9 to 2.6 pixels after consistency optimisation.
• articleWhere does the 'optical-flow magnitude falls from 6.9 to 2.6 pixels' figure for GeoFlow come from?
  Problem. C3-B139-W28-06 attributes to GeoFlow a flow-magnitude drop (6.9 to 2.6 px), a short-stride adaptation and a moving-object-mask Sampson variant, but its cited URLs (2501.06336, 2504.00983, 2510.21615, 2512.22274) do not contain these figures; 2510.21615 only cites GeoFlow. Method. The figures are in GeoFlow itself, arXiv 2605.18365, which the candidate does not list. Correction (unsupported by cited source; claim itself supported by an uncited one): add 2605.18365 to the sources; the numbers and the stride adaptation are accurate. Limitations. Only the two quoted statements were confirmed. Version. arXiv 2605.18365, current HTML.
• articleIs there a paper in the COLMAP-success set that reports a roughly 1% failure rate on generated video?
  Problem. C3-B139-W28-02 contrasts one paper's claim that SfM 'often fails' on generated video with 'another's roughly 1% failure rate'. Method. Searched all four cited papers (GTA 2605.12957, ViCoDR 2511.18991, WorldPrompter 2504.02045, SGC 2603.19048) for failure or success figures near 1%. None found: GTA success 82.9-91.4%, ViCoDR 86.3-92.3%, WorldPrompter reports 0% failures for its own method (89.7% for 360DVD). Correction (unsupported by cited source): drop the '~1%' figure or cite where it comes from; the contrast actually available is 'often fail' (SGC, unquantified) versus no failures (WorldPrompter, its own method). Limitations. A paper outside the cited list may carry a 1% figure. Version. arXiv HTML as fetched.
• articleWhat rules does Don Carson's environmental-storytelling essay give for a consistent, readable story world?
  Problem. Spaces that look good but tell nothing, or break their own rules. Conditions. Game or themed-environment design (essay from March 1, 2000, drawing on theme-park practice). Method. (1) Define a big-picture story as a set of rules guiding design and team; never break those rules. (2) Answer 'Where am I?' within the first 15 seconds, then 'What is my relationship to this place?' through clues rather than text dumps. (3) Use cause-and-effect vignettes: staged areas that let the player conclude what happened (broken doors, a crashed vehicle, charred remains), also to show time passing or player-caused changes. (4) Follow 'bread crumb' trails left by a fictional predecessor. (5) Give familiar anchors in alien environments. Failure modes. Adding elements just because they are cool; alienating all-alien levels. Limitations. Craft essay with examples from 1990s games and attractions, not empirical evidence. Version/date. Page dated March 1, 2000; fetched 2026-10-23.
• articleHow should detail, light and props be placed to direct attention in a story space, per Carson?
  Problem. Over-detailed, evenly lit spaces hide story cues. Conditions. 3D level or set design. Method. (1) Use contrast: a large room with one shaft of light on a solitary prop beats a room full of detailed elements; make other props supporting players to the important story element. (2) Use fewer, quieter textures and save the most decorative element for the end of a corridor to pull the viewer on. (3) Avoid flooding a level with light, which flattens depth; let large areas fall into shadow while not hiding vital game elements. (4) Do not offer too many choices at once. (5) Treat texture maps as stage canvas, not wallpaper. Failure modes. Lighting that reveals every nook; cluttered high-frequency textures. Limitations. Craft guidance from an era of limited rendering; principles are compositional. Version/date. Essay dated March 1, 2000; fetched 2026-10-23.
• articleWhat four ways does Henry Jenkins say game spaces carry story (evocative, enacted, embedded, emergent), and how do they combine?
  Problem. The ludology/narratology dispute stalls practical design. Conditions. Designing spatial or open-world narrative. Method. Jenkins proposes game designers as narrative architects. Environmental storytelling sets the preconditions for narrative in at least one of four ways: spaces evoke pre-existing narrative associations (genre/story worlds), act as a staging ground for enacted events, embed narrative information in the mise-en-scene for players to discover, or supply resources for emergent narratives (his example: The Sims). Detective-style design: a loosely structured story driven by the player's exploration plus a pre-structured one embedded in the space awaiting discovery; mixing enacted and embedded elements balances interactivity flexibility with coherence of a pre-authored narrative. Failure modes. Treating a space as empty of narrative because it lacks cutscenes. Limitations. Essay from the early 2000s with game examples (Myst, Half-Life, The Sims); fetched text carri...
• articleHow should an AI world or scene generator place story cues, combining Carson's and Jenkins's craft?
  Problem. Generated scenes are often visually dense but narratively empty or contradictory. Synthesis (inference, built from findings 11 to 13, not from a source recommendation). (1) Start from a rules statement for the world and check every generated element against it (Carson: do not break the rules). (2) Make the first view answer where the player is within about 15 seconds, using one dominant landmark and a few genre-evoking cues (Jenkins: evocative spaces). (3) Place a small number of cause-and-effect vignettes with clear traces of a prior event, each with a single highlighted focal prop (Carson: vignettes, single shaft of light). (4) Tag each cue as evocative, enacted, embedded or emergent and make sure embedded cues are consistent with the story ledger and discoverable. (5) Reserve decoration to lead the eye toward the next space; avoid evenly lit clutter. (6) Keep a list of cues so later scenes can alter them to show time passing. Failure modes. Random props that contradict t...
• articleHow does IIIF Image API 3.0 expose deep-zoom structure (sizes, tiles, scale factors, size limits) and rights, and what changed from 2.1?
  IIIF Image API 3.0 exposes multi-resolution structure in info.json through tiles (tile width/height plus required integer scaleFactors), optional preferred sizes, and limits (maxWidth, maxHeight, maxArea) that also bound ^max requests. Rights are one URI (Creative Commons, RightsStatements.org or a registered extension), replacing 2.1's attribution, license and logo properties. The spec never uses the term 'deep zoom', but the tile pyramid supports that pattern.
• articleWhere do I find what changed between OpenUSD releases, and which tag is the newest one I can read about?
  OpenUSD records release changes in a single CHANGELOG.md, one section per release, grouped by area with '**Important**' markers. The 2026-10-21 observation that the newest tag (v26.11.0) had no GitHub Release is out of date. v26.11.1 was tagged and published as a GitHub Release at 2026-10-21T23:36Z with a GPU memory fix and a CI change, while v26.11.0 itself still has no Release entry. 26.11.0's Important security item drops default reading of .usd/.usdc files older than crate version 0.4.0.
• articleWhat does the Core Specification v1.0.1 normatively cover for USD, and what does it explicitly leave out?
  The AOUSD Core Specification 1.0.1 normatively covers USD's core: data types, document data model, paths, composition, stage population, value resolution, schema extension fields and file formats. It explicitly leaves domain uses (geometry, materials, physics) to other AOUSD specifications, keeps interpolation methods out of compliance validation and reserves fields such as expressionVariables and colorManagementSystem. The supplemental sample implementations are reference quality and not normative.
• articleHow do UsdSemantics labels inherit, and what did the release notes change for UsdPhysics and render-settings handling between v25.05 and v26.11?
  UsdSemantics labels inherit down the hierarchy by accumulating (descendants keep their own labels and gain their ancestors'), there is no registry of taxonomies, and all labels carry equal weight. Per the OpenUSD changelog: UsdPhysics gained a parsing utility and validators in 25.05, nested rigid bodies and articulation for kinematic bodies in 25.11, deprecations of the custom-token and loader names in 26.05, more validators in 26.08, and in 26.11 bodies with rigidBodyEnabled = false are treated as not applied. Render settings: in 25.11 RenderMan expects relationships rather than connections for filters and integrators; 26.03 added HdRenderSettingsSchema fields; 26.08 allows interactive rendering with a RenderSettings prim; 26.11 announces in-band transport through scene indices.
• articleWhich schemas were added or changed in OpenUSD releases from v25.02 to v26.11, and what is each for?
  From OpenUSD's CHANGELOG at 5b3c21a: 24.11 added usdSemantics' multi-apply SemanticsLabelsAPI (shipped as semantics:labels:<taxonomy>, reversing the proposal's order); 25.02 added the usdview Resolved Labels row and an example asset; 25.05 a multi-apply AccessibilityAPI; 25.11 the uiHints classes; 26.03 the UsdVolParticleField family including 3D Gaussian splats; 26.05 an explicit UsdCollectionAPI mode; 26.08 LOD schemas, UsdProfiles and HydraRenderPassAPI; 26.11 UsdMediaAuthorshipAPI, the BackPlateAPI luma renames (gamma to power, lift to offset, gain to slope) and apiSchemaCanOnlyApplyTo for applied schemas.
• articleWhat does a first-person crew account of a splat-on-LED job look like, and does the best one found involve a world model?
  Partially verified: the curator re-read none of the cited sources; S9, S10 rest on the producer's pinned reading. The only first-person crew account found (DOSENMUTTER, Filmakademie, 2026-07-08) uses a captured photogrammetric splat, not a generated world; AI appears only as denoising. It is useful as a template of what is missing from the generative cases: stated alternatives tested (plates vs splat), a stated reason, capture counts and named roles. Berlin (Volinga case, reported by Radiance Fields) is likewise capture-based. Neither is evidence about world models.
• articleBeginner: has any film, advertising, series or game job reported using an action-conditioned interactive world model (Genie 3 / Project Genie, Odyssey-2, Runway GWM-1, NVIDIA Cosmos) with a measured outcome?
  Partially verified: the curator re-read none of the cited sources; S7, S8 rest on the producer's pinned reading. Negative result, bounded: no production case with a measured outcome was found for interactive/action-conditioned world models. The two company pages read first-hand (Odyssey-2, Runway GWM-1) list media uses as expected or listed applications and name no customer or result. Search found nothing further, and two sources (Project Genie blog, an ACM paper) could not be read. This is absence within the pages read plus discovery searches, not proof of absence.
• articleDo independent creators' micro-shorts, episodic and VR/game prototypes built on AI-generated worlds report any measured outcome (time, rework, shots used, ratings)?
  Partially verified: the curator re-read none of the cited sources; S3, S4, S5 rest on the producer's pinned reading. Four creator projects (Alarm, Cryptid Worlds, Memory House, Splat World) are documented on World Labs pages dated 2025-11-12. They describe workflows and qualitative outcomes (consistency, 'within hours', platform stability) but no measured time, cost, shots used, rework or quality ratings. Evidence class: vendor-authored case studies quoting the creators.
• articleHow well have these benchmarks validated their automatic physics judges against humans, and can their validation numbers be compared?
  Partially verified: the curator re-read none of the cited sources; S1, S2, S4, S9, S12 rest on the producer's pinned reading. Five papers validate a judge or automatic scorer, each with a different statistic: VideoPhy-2-Autoeval Pearson 0.37 on physical commonsense (Gemini-2.0-Flash-Exp 0.11); PhyWorldBench's CAP ROC-AUC 75.1 for physical commonsense (plain GPT-o1 61.6); PhyGround's PhyJudge-9B aggregate relative bias 3.3 percent (Gemini-3.1-Pro 16.6) on held-out Veo-3.1 videos only; Last Exam's measurement evaluator 51.6 percent within-task pair agreement against 43.4 for a direct Qwen3.6-27B scorer and 56.6 between humans; Principia's VLMs 0.50-0.66 agreement with binary truth. The statistics are not comparable, none reports the same data for two judges, and all are the benchmark authors' own checks; the consistent message is that prompted general VLMs are weak physics judges and that fine-tuning or measurement helps modestly.
• articleHow does World Models' Last Exam in Physics test mechanics, optics, fluids and electromagnetism by measurement rather than by a VLM, and what do eight current video models score?
  Partially verified: the curator re-read none of the cited sources; S9, S11, S10 rest on the producer's pinned reading. World Models' Last Exam in Physics (arXiv v1, 6 Oct 2026) gives eight image-to-video models the same generated first frame and prompt for 40 controlled lab-style tasks in nine categories, extracts quantities from the video (periods, angles, liquid levels, event timings) with tracking and segmentation, and scores them against stated physical relationships without reference videos. A Qwen3.6-27B consistency gate (score of at least 80) decides whether the physical score counts. Seedance 2.5 averages 57.76/100, MiniMax H3 54.89 and CogVideoX1.5-5B 18.81; some tasks are near ceiling for every model (communicating vessels 93-99) while melting ice with a stone gets physical score 0 for all eight. Against 10 human annotators the evaluator beats a direct Qwen3.6-27B scorer (51.6 vs 43.4 percent pair agreement) but stays below human-human agreement (56.6).
• articleWhich quality claims in these 3D generation releases are measured results, which are vendor claims, and where do tables reuse or anonymise rows?
  Partially verified: the curator re-read none of the cited sources; S6, S29, S30, S34, S31, S28, S27 rest on the producer's pinned reading. All quantitative comparisons inspected were run and reported by the releasing teams; none is an independent evaluation. Three flags for curation: (1) the Hunyuan3D-2 README table lists "Top Open-source Model1" with numbers identical to the Trellis row in the Hunyuan 2.0 paper, and three unnamed closed-source rows; (2) Michelangelo, Craftsman 1.5 and Trellis rows in the Hunyuan 2.1 shape table are numerically identical to the same rows in the 2.0 paper, and the 2.1 texture table repeats the 2.0 paper Paint CLIP-FID, CMMD and CLIP values for "Hunyuan3D-2.0" but with a different LPIPS (0.1261 vs 0.0059); (3) the 2.1 title says "Production-Ready PBR Material" while its tables are image-level similarity metrics and contain no PBR-correctness or topology test. TripoSG ranks against methods with an LMM judge, and its VAE metrics are on its own data.
• articleInstead of trusting an LLM to simulate each step, can it write an explicit rule model (PDDL) that a validator and planner then use, and how many errors did the LLM make doing so?
  Partially verified: the curator re-read none of the cited sources; S3 rests on the producer's pinned reading. Guan et al. (NeurIPS 2023, arXiv 2305.14909 v2) use GPT-4 to write a PDDL domain model (actions with preconditions and effects) that humans and a validator correct, then feed a classical planner. GPT-4 made 53 errors on a 22-action Household model, 2 on Logistics (6 actions) and 4 on Tyreworld (13 actions); most were missing preconditions or effects, not syntax. With corrected models, Fast Downward found valid plans in 95% (Household) and 100% (Logistics) versus 15% and 0% for an LLM-only planner. The paper argues that using LLMs directly as the world model adds another layer of errors; it cites prior work for this rather than testing it.
• articleOn the Final Twist job, where in the pipeline did a generated Gaussian-splat world sit, what came in and out, and what outcome do the two accounts state?
  Promise (producer) and World Labs (vendor) describe the same job: ten crime-scene environments rebuilt from low-quality archival photos for Harlan Coben's Final Twist. Steps: AI restoration of the images, a World Labs tool producing a Gaussian splat, artist rebuild of geometry and textures, optimisation, display on a 16K LED wall. The outcomes stated are ten environments and qualitative benefits (natural lighting, presence); no time, cost, shot or quality number is given by either page. The two pages disagree on naming (a "tool from World Labs" versus Marble) and carry different dates.

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