# Muscle Groups 3D — experimental asset Local study for A-253, prepared 2026-09-10. Valentine accepted the material treatment, complete anatomical head and conservative whole-body surface cleanup. Both replacement-head trials were rejected and abandoned. The exact accepted anatomical model, including the original skull, facial musculature and neck, has been restored. The 23 muscle groups and Playground Shell layout remain. This is not a replacement for Freak Workouts production illustrations. The public, no-index route is `/muscle-groups-3d`. ## Model and attribution `body.glb` is a genuine, editable 3D head-to-feet model. It contains separate muscular meshes and matching craniofacial skull support, including both sides of the 23 confirmed catalogue groups. It can be imported into an application supporting glTF 2.0. It has no rig or animation. - **Z-Anatomy — The libre 3D atlas of anatomy — CC BY-SA 4.0.** Original project: https://github.com/Z-Anatomy/Models-of-human-anatomy Model design, anatomy and 3D work: Gauthier Kervyn and contributors. - **BodyParts3D — The Database Center for Life Science.** Original model: Kousaku Okubo / DBCLS. Z-Anatomy's notice records its BodyParts3D lineage under CC BY-SA 2.1 Japan; the current original dataset license is recorded at https://dbarchive.biosciencedbc.jp/en/bodyparts3d/lic.html. - Acquired muscle-system GLB conversion: https://github.com/Liyucheng1997/242_lab-human-anatomy/blob/322ba39e96ea91ce08601caad2c0aaade1dc99f0/public/models/muscular.glb - Matching craniofacial skeleton source (same revision and atlas): https://github.com/Liyucheng1997/242_lab-human-anatomy/blob/322ba39e96ea91ce08601caad2c0aaade1dc99f0/public/models/skeleton.glb - Model license and derived render license: **CC BY-SA 4.0**, https://creativecommons.org/licenses/by-sa/4.0/. Preserve attribution, indicate changes, and retain the same license when distributing this adapted model or derived images. This does not relicense unrelated website source. Keep these obligations in the future app/web asset decision; this task makes no production asset decision. `LICENSE.source.txt` preserves the upstream notice. Body geometry comes from the muscular system; a restricted matching craniofacial skeleton selection supports the complete anatomical head. No replacement head, MakeHuman asset, auditory ossicles, kidney, inner-ear, nervous-system or other separately licensed organ model is included. No upstream medical descriptions were copied. ## Treatment and coverage - Baked the source node transforms, including mirrored-side winding. - Restored the complete head and facial musculature from the pinned source, including the epicranial aponeurosis that forms the crown. There is no upper crop. Only the existing ground-plane cut at 0 metres remains. Full-body framing includes the crown and feet; the Neck preset also includes the head. - Added craniofacial bones, teeth and nasal cartilage from the matching skeletal source under the facial muscles. These remain neutral support geometry; they do not add muscle groups. Sinus volumes, auditory ossicles and the rest of the skeleton are excluded by the decoder’s explicit `skull` selection. - Audited every retained muscular-system structure against its source surface before applying 2 mm vertex clustering. Reject the reduction if it increases boundary or nonmanifold edges, changes the number of connected components, or changes the Euler characteristic. In those cases, use duplicate-corner welding at 1 micrometre precision to preserve thin layers. The audit covers the head and neck, trunk, limbs, tendons, retinacula and other retained muscular-system coverings. Genuine source openings remain intact; separate muscles are never fused. The existing 55 neutral skull-support parts keep their accepted conversion. - Removed coincident duplicate triangles and collapsed triangles from newly reviewed source surfaces. These triangles add no independent visible anatomy. The whole-body cleanup omitted no additional structures. - Applied eight gentle Taubin smoothing pairs. Recomputed area-weighted normals and diffused fine normal variation over five passes for a softer surface. - For the bilateral external/internal abdominal obliques, rectus abdominis, wrist retinacula and palmar aponeuroses, replaced coarse clustering with duplicate-corner welding at 1 micrometre precision. This preserves opposite sides of thin layers and avoids the perforations and nonmanifold edges that the coarse reduction introduced. Source topology is retained, including the internal oblique source's small pre-existing topology defects. - Closed each palmar aponeurosis's 32-edge internal opening with concave, winding-preserving triangulation. Kept the 182-edge external palm/finger outline, then subdivided the covering twice before smoothing. A tapered front relief of up to 6 mm across source y = 0.72–0.855 m keeps underlying tendons beneath the illustration surface. The two neutral superficial transverse metacarpal ligaments were omitted because they intersect this covering. This is a simplified palm treatment, not anatomical tissue thickness. All 23 muscle groups and the complete head remain. The subsequent whole-body pass preserves all 12 accepted abdominal/wrist/palm source treatments exactly. - Matched all 23 user-confirmed Admin Console names in `lib/anatomical-body/catalogue.json`. That file is shared by the UI and converter. Every selection includes left and right geometry. The same structure can belong to more than one fitness group: gluteus medius/minimus overlap Glutes and Abductors, and the distal wrist region overlaps Forearms. - Kept the source's three deltoid parts separately selectable. Chest uses the clavicular head for Upper Chest and a regional split of the sternocostal surface for Middle/Lower Chest; the abdominal portion also belongs to Lower Chest. The split follows y = 1.26 + 0.3 × abs(x) in source metres. These are illustrative training regions, not three independent muscles or validated exercise-emphasis boundaries. - Obliques highlights the lateral surfaces beyond 0.075 m from the midline; the broad central aponeurosis remains neutral in this regional illustration. - Lower Back selects lumbar structures and the lumbar region of long spinal muscles below 1.18 m. Wrists selects distal structures between 0.81 and 0.925 m. Those source-coordinate regions are encoded per triangle, retaining shared positions and normals so the neutral body has no artificial surface seam. - Mid-Back exposes the rhomboids by hiding the trapezius. Lower Back hides the lats to expose lumbar structures. These solid dissection views are identified in the controls sidebar; the same visibility applies to the shadow pass. - Added opaque Ivory, Graphite, White, and Black themes and Teal, Sage, Clay, and Slate muscle highlights in the viewer. GLB's neutral material permits reuse independent of the viewer; the selected color is a renderer setting. - In the viewer only, the rectus highlight receives an approximately 18 mm camera-depth offset to remain legible under the source's thin abdominal coverings. This is an illustration treatment; it does not move the stored GLB geometry or represent a dissection. Review this treatment before reuse. These are aesthetic transformations of a sourced model; they are not proof of anatomical accuracy. Review silhouette, attachments, depth, laterality, and the meaning of each group before using the illustrations educationally. ## Reproduction `provenance.json` records the source revision, source and output SHA-256, modifications, mesh names, overlapping group assignments and dissection visibility. No external request is made when viewing the prepared local GLB. Acquire both pinned GLBs (`muscular.glb` and `skeleton.glb`) and Google's standalone Draco 1.5.7 decoder (`draco_decoder_gltf_nodejs.js` plus its companion WASM) into a task-owned workspace folder. Preserve the Draco Apache-2.0 license with that helper. The decoder is offline conversion tooling only; it is not a site dependency. Then, from the site repository: ```sh node scripts/decode-anatomical-source.cjs /path/to/muscular.glb /path/to/draco_decoder_gltf_nodejs.cjs /path/to/source/decoded.json node scripts/decode-anatomical-source.cjs /path/to/skeleton.glb /path/to/draco_decoder_gltf_nodejs.cjs /path/to/source/decoded-skull.json skull python3 scripts/prepare-anatomical-body.py /path/to/source python3 scripts/test_anatomical_surface.py ``` The prepare command writes the anatomical model to `public/anatomical-body/body.glb` and its matching `provenance.json`. There is no replacement-head profile or head-refitting step. The prepare script checks both pinned source digests, skull coverage and any missing group or missing bilateral coverage. `scripts/anatomical_surface.py` owns the surface cleanup and fails if the pinned palm topology changes. The converter records each structure's source/reduced connectivity and selected treatment in `provenance.json` → `surfaceCleanup.topologyAudit`. Its geometry-only tests check concave triangulation and winding, thin-layer preservation, subdivision extent, the relief's limits, rejection of punctured/fused reductions, and redundant-face cleanup. No image-generation service or raster-to-3D conversion is involved. ## Image export The Export section exports the current camera, theme, and highlight color as a square PNG, up to 2000 × 2000. The transparent option removes the stage background; an attribution strip remains at the lower edge. Keep the full source/changes notice with distributed images. An exported image is a render of this same 3D geometry, not a separate generated interpretation. ## Selection and framing The page starts with the complete head-to-feet figure. Choosing a group moves and frames the camera around that region; Full body returns to the overview without clearing its highlight. All 23 exact names appear in a list with a persistent vertical scrollbar and no search field. Clear selection is a separate outlined action above the list; selected rows use the site's monochrome styling. Show chooses Full body or Focus group; View chooses Front, Angle, or Back. Manual camera movement or rotation changes the View display to Custom, and choosing a view preset stops rotation. Focus group is disabled without a selection. Style contains Theme and Highlight color dropdowns with color swatches in the selected value and menu options, followed by Light softness. Framing, Zoom, camera views, Rotate, mouse/touch/keyboard selection, materials, and PNG export remain local to this experiment. The shared Playground Shell places all controls in its left sidebar and the model in the preview, with no code column. In the desktop column layout, only the controls scroll; the preview fills the remaining viewport height and stays in place. Below 768px, the preview comes first, followed by all controls in one column in normal document flow. The 52.9 MB uncompressed anatomical model is a study asset; its earlier 36.6 MB reduction was replaced to keep thin surfaces intact. Production compression, a rig, and final anatomical/visual acceptance are outside this prototype's scope. ## Accepted visual direction On 2026-09-10 Valentine confirmed the existing visual treatment and requested one correction: show the complete body, including the complete head. Keep the solid, softly sculpted material treatment. The head belongs in the reusable model and full-body framing; focused camera crops must not remove source geometry. Valentine accepted the restored complete head that day, then requested the shared Playground Shell with left-side controls and no code column. The later layout correction retains the shell's standard Controls / Adjust the behavior and Muscle Groups 3D / Visual Preview headers, matching Card Fan. Component back links return to `/tools`. Omit additional decorative headings and captions; retain model attribution and the notes explaining deeper-group dissection views in the sidebar. Valentine then requested fewer distracting holes and torn-looking details, pointing to the abdomen and palms. The adapted surfaces are in the reusable GLB and export with the same model. The 2026-09-10 local check confirmed all 23 bilateral visible highlights, unchanged complete-head support, and the targeted surface topology. Valentine accepted that treatment on 2026-09-10, then requested the same conservative review throughout the model, highlighting pits over the neck/clavicle. Preserve scientific muscle forms, attachments and separations; remove distracting defects without over-simplifying the anatomy. The resulting whole-body cleanup was visually accepted by Valentine on 2026-09-10. Local verification on 2026-09-10 audited all 565 retained muscular-system source structures: 526 use fine welding (including the 12 accepted treatments), and 39 retain clustering that passes the connectivity guard. Removed 4,584 redundant source triangles in the newly reviewed surfaces. All 646 output parts and their group/visibility masks remain; 110 parts are byte-identical to the accepted baseline, including the 12 accepted source treatments and all 55 skull-support parts. Every newly reviewed closed, manifold source remains closed and manifold after smoothing and ground clipping. The platysma, sternocleidomastoid, chest, iliotibial tract and knee/ankle retinacula have no introduced open or nonmanifold edges. Existing source openings and defects remain where the guard preserves them; this is not a blanket hole-fill operation. Seven geometry-only regression tests and offline renders of all 23 bilateral highlights passed. Front, side and back inspection retained the full-body silhouette and muscle separations. These checks inspect the actual GLB; they do not establish browser runtime performance or final anatomical acceptance. No website build or server launch was run for this surface pass. Valentine subsequently tried two replacement-head directions and rejected both. On 2026-09-10 he explicitly abandoned head redesign and requested the original anatomical skull as it stood before either trial. The original model, provenance and conversion script were restored byte-for-byte from the verified snapshot created immediately after the accepted whole-body cleanup. This also undoes all replacement-related neck fitting. Replacement-head modules, tests, source assets and their additional license file were removed from the active project. Restoration checks: the complete GLB matches its pre-trial SHA-256 `1657c2ac1bf71fdab3ed71cd1e410962e2f64becaac4233c95fab19d8426bab9`; all 646 parts, including 55 skull-support parts and all 23 bilateral selections, are restored exactly. The renderer, catalogue, route and Playground Shell files are unchanged. No product build, server launch or deployment was run. The head redesign is abandoned; any broader browser/performance review remains separate.