Fallingwater in Blender: GPT-6 Astra

# Fallingwater: faithful, photorealistic, fully explorable Blender reconstruction

**Execution PRD — researched 7 September 2026.** This is the specification for the later build goal. The current preparation phase gathered evidence and tested Blender control; it did not build the house. When the user starts a goal to execute this file, carry the work through to the deliverables and verified acceptance gates below. Do not stop after another plan, an exterior blockout, one attractive render, or a script that merely runs.

## 1. The intended result

Build Frank Lloyd Wright's **Fallingwater in Blender**, including the main house, guest house and staff/service spaces, connecting circulation, terraces, pools, waterfall, rock formations, and surrounding woodland visible during exploration. The user must be able to look around the exterior and freely fly through the different rooms in a coherent, fully modeled scene.

The visual ambition is photographic credibility at first glance from a distance, with carefully observed geometry and materials that hold up at human viewing distances. The house must be recognizably this particular building: its measured proportions, masonry, cantilevers, glazing, intimate rooms, built-in furniture and relationship to Bear Run. No final placeholder shapes, swollen furniture, rounded rock blobs, generic modern interiors, featureless stone walls, or flat blue water.

**User-confirmed setting:** the **restored house with documented furnishings, in lush late summer**. Treat this as a clean conserved presentation informed by the latest verified condition, rather than a claim to reproduce one survey of every detail on an exact day. Retain documented permanent museum-era alterations, including the enclosed former carports. Exclude temporary scaffolding, conservation coverings and transient visitors from the presentation. Record any other presentational omission, such as a movable visitor barrier, so it cannot be mistaken for a measured change.

The project has two equally necessary quality dimensions: **architectural fidelity** and **convincing appearance**. Neither compensates for failure of the other. A beautiful invented room fails; an accurate but visibly crude room also fails.

## 2. Read and use this research before construction

Read these files fully; they are part of this specification. Open the actual drawings and photographs, not just the written summaries.

1. [Architectural evidence, every-space inventory and dimension anchors](research/architecture-agent.md).
2. [Room references, furnishings, materials and source caveats](research/interiors-agent.md).
3. [Blender 5.1 realism methods, navigation, QA and open-source tooling audit](research/blender-realism-agent.md).
4. [Tested Blender MCP/API decision, setup and fallback client](research/blender-control.md).
5. [Research index and known gaps](research/README.md).

The primary geometry archive is already downloaded: **11 main-house HABS sheets and 4 guest-house sheets**, full-resolution TIFFs, readable rotated previews and detail crops under `references/architecture/`. `drawing-downloads.json` is the per-sheet provenance/checksum manifest. Supporting PDFs include survey data, caption lists, the official visitor guide, Avery's drawing inventory and the preservation-scanning paper. The separate interiors directory contains photographs, contact sheets and tour metadata indexed by its manifests.

### Evidence hierarchy

| Question | Use first | Cross-check |
|---|---|---|
| Built geometry, topology, openings and level relationships | LOC HABS PA-5346 (`pa1690`) and PA-5346-A (`pa2187`) plans, sections, elevations and details | Independent elevations, photographs and newer documented interventions |
| Current restored appearance | Dated Fallingwater/WPC preservation and collections material | University and archival photographs with their age/state recorded |
| Furniture, fixtures, joinery and room identity | Official collection/conservation records plus identified room photographs | HABS detail sheets and plan positions |
| Site and waterfall form | HABS relationships/elevations and multiple actual site photographs | Appropriate public elevation data if verified useful; never generic terrain alone |
| Blender behavior | Installed 5.1.2 RNA/API, official versioned manual and actual local tests | Reviewed source of a specifically useful library/add-on |

Original Wright designs at Avery/JSTOR are discovery/corroboration sources, not automatic overrides of the built house. Generic stock assets and generated images are not architectural evidence. When sources disagree, record the specific conflict, dates and chosen interpretation.

### High-impact facts and traps already established

- Main plans are sheets **3–6**, elevations **7–9**, sections **10**, and fireplace/hatch/desk/lamp details **11**. Guest sheets **1–2** give levels, **3–4** elevations/section. See the linked architecture inventory for exact URLs and local files.
- Main sheet 4 labels the living space **48 ft × 33 ft 8 in**, the kitchen **15 ft 9 in × 12 ft**, and the servant's sitting room **11 ft 5 in × 9 ft 4 in**. These are anchors, not instructions to replace irregular outlines with rectangles. [Main first-floor drawing](https://www.loc.gov/resource/hhh.pa1690.sheet/?sp=4).
- Floor/terrace datums and roof surfaces differ. The third-level annotation **+17′-3/4″** means 17 feet plus three quarters of an inch. The guest house has an independent drawing datum; setting both buildings to world Z=0 is wrong. Follow leaders and sections, not one blanket floor-height increment.
- The site sheet explicitly describes the road/path/stream locations as approximate. Do not market the resulting terrain as survey-exact. [Site drawing](https://www.loc.gov/resource/hhh.pa1690.sheet/?sp=2).
- The university reference directory's `2018` name does not establish photo capture dates. Much of its exterior imagery is leaf-off. The tour also contains an unrelated ornate-hall scene ending **`_102`**; exclude it. A maintenance-state panorama with covered furnishings is not a styling reference. Follow the interiors note's exclusions and room mapping.
- Distinguish the **main-house plunge pool** from the **guest-house swimming pool**. The Columbia photos named `0_pool1` and `0_pool2` are not automatic guest-pool evidence.
- Later conservation sources supersede older descriptions where relevant, including the kitchen floor. The World Heritage Preserved blog documents recent work and removal of scaffolding for the 2026 reopening. [Current preservation record](https://fallingwater.org/projects/world-heritage-preservation/).
- Preservation teams created extensive CAD and hundreds of laser scans, but this research did **not** obtain their raw registered scan/CAD data. Public references support a detailed reconstruction, not a truthful promise of every hidden surface being exact. [Primary documentation paper](https://isprs-archives.copernicus.org/articles/XLII-2-W5/389/2017/).

## 3. Scope and room completeness

Expand **every space ID in the architecture note** into `data/rooms.csv` or equivalent before modeling. Each independent bath, staff room, terrace, stair, service space and structural bay needs its own row. Do not turn grouped notation such as `SINGLE-A/B` into one object or one unchecked status.

| Area | Required coverage |
|---|---|
| Main basement/river level | Wine cellar, bath, boiler room, service circulation, three structural bays and rock interfaces; plunge pool and stream access |
| Main first floor | Entry, coats, loggia, living and dining areas, hearth, reading/built-in areas, kitchen, servant's sitting room, service connections, terraces, hatch and hanging stair |
| Main second floor | Master/Liliane suite, dressing/Edgar Sr. suite, guest suite, **three separate baths**, hall/stairs, each terrace and enclosed connecting bridge |
| Main third floor | Study/library, bath, narrow gallery, sleeping alcove, terrace, relevant exterior connections |
| Guest basement | Laundry, bath and connecting stair |
| Guest principal floor | Lounge, guest bedroom, bath, boiler space, chauffeur's lounge, theater/enclosed former-carport area, car court, terrace, pool and steps |
| Guest upper floor | One double staff room, two single staff rooms, shared bath, hall/stairs and terrace |
| Shared exterior | Covered walkway, bridge/drive, all façades and undersides, roofs visible from orbit, waterfall tiers, streambed/banks, major rock ledges, planting and woodland context |

This scope is defined by the source inventory rather than a promotional total “room count.” Dining is part of the open living space; foundation bays are not bedrooms. Room aliases must map to the plan labels. Contemporary use of sparsely documented service areas must remain explicit if unverified.

Each room needs complete enclosing geometry, appropriate openings and circulation, observed finishes, built-ins/furnishings/fixtures where evidenced, and a believable treatment of poorly documented surfaces. Track `plan_sources`, `photo_sources`, `era`, `confidence`, `geometry`, `materials`, `furnishings`, `navigation`, `visual_qa`, and `remaining_defects`. Missing imagery is not permission to omit a room or represent an invented layout as fact.

Research unknowns before constructing the affected element. When further public evidence cannot resolve a detail, use a conservative, internally coherent reconstruction grounded in adjoining evidence and mark it **inferred** in the ledger. Do not stall the whole project indefinitely or claim the unknown has been verified. No outreach to archives, purchases, paid API use or public publishing is included in this goal without user authorization.

## 4. Execution environment and control

Use the tested **Blender 5.1.2** installation and Metal GPU on this **M4 Max / 64 GB** Mac. The current scene tests verified Cycles GPU and EEVEE on a factory cube; they do not establish final-scene frame rate or render cost. Preserve the evidence in `research/preflight/`.

Use the already configured **official Blender Lab MCP** for live scene inspection, small corrections, API lookup and image capture. Keep reusable `bpy` construction scripts as the source of repeatable operations. Official MCP source commit and the necessary **MCP SDK 1.30.0 pin** are documented in `research/blender-control.md`; preserve them. When native tools are unavailable, use `scripts/blender_mcp_client.py`, which was verified against the actual official server.

For full-resolution visual review, save a screenshot or render to a local path and open the image. The official inline screenshot transfer failed in preflight, whereas the path-based method worked. Do not repeatedly call a failing image endpoint or treat its failure as a reason to skip QA.

`scripts/launch_blender.command` starts Blender with the networking mode required by the localhost MCP bridge. Confirm which file is open before any mutation. Save milestone files before risky operations, preserve user edits, and modify only owned collections. Prefer the data API/BMesh for bulk work; provide explicit context for operators. Keep scene mutations on Blender's main thread and through one writer. Independent agents may research, prepare assets or review outputs; they must not race on the same `.blend`.

### Storage and organization

Internal free space was about **19 GiB** at preflight. The mounted external drive had approximately **1.1 TiB available**. Recheck capacity and sustained write behavior before production. Create a dedicated external project directory, proposed as `<external drive>/Fallingwater/`, for large textures, `.blend` checkpoints, caches, final render sequences and portable delivery. Keep source scripts, research, parameter files, compact QA reports and a `DELIVERY.md` path map in this workspace. Do not delete unrelated files to make room or duplicate huge assets unnecessarily.

Use meaningful collections, for example `SITE`, `MAIN/L01/ARCH`, `MAIN/L01/FURNITURE`, `GUEST/L02`, `WATER`, `VEGETATION`, `LIGHTS`, `CAMERAS_QA`, and `CAMERAS_PRESENTATION`. Keep parameterized base construction distinct from accepted manual refinements, with a deterministic seed and stage ownership. Every hand refinement must be saved and survive rebuilding a different stage.

Keep linked resources relative within the delivery directory. Do not pack all photographic research or an entire third-party library into the production file. Include just the required distributable assets and record their source, version, scale and license. Maintain a dependency manifest and resumable stage logs.

## 5. Geometry and registration requirements

Set **1 Blender unit = 1 metre**, scale 1. Convert feet/inches exactly using 1 ft = 0.3048 m. Establish local origin, north and an explicit elevation datum. Do not use a giant geospatial coordinate as the modeling origin.

Register each plan from multiple dimension/scale-bar anchors and shared masonry corners or stair cores. Original TIFFs and insets can have different orientation/scales; a resized preview's nominal print scale is not valid pixel calibration. Preserve source endpoints, actual pixel coordinates, units, inferred uncertainty and residuals in `data/dimensions.csv`. Separate explicitly dimensioned values from raster estimates.

Trace irregular slabs, recesses, chimney/stone cores, parapets, curved terrace ends, roof edges and glazing. Solve floor, soffit, slab, terrace and stair levels through coordinated sections. Resolve the guest-house offset before committing to the connected walkway. Check stair count/rise/run and headroom against actual evidence; do not enlarge low rooms or narrow passages to accommodate a default avatar.

Build all sides of each room and visible exterior assembly. Include wall/slab thickness, thresholds, window reveals, door frames/leaves, soffits, roofs, terrace undersides, exposed supports, stair voids and drain/roof junctions visible from the allowed camera space. Doors must open in a plausible way or be intentionally posed for access. A door texture on a sealed wall fails.

Model the particular masonry: long irregular horizontal courses, varying projections, recessed mortar, real corners/returns, lintels and stone/steel/wood junctions. Trace distinctive photographed hero stones and hearth contours when visible. A generic repeating brick shader cannot define the stonework. Use physical geometry for silhouette, parallax and cast-shadow details; controlled displacement/bump for smaller relief.

Keep manufactured planes intentional and edges softly bevelled at believable scale. Do not apply broad subdivision to the whole building. Use true mesh bevels where needed in both renderers; a Cycles-only Bevel shader does not solve EEVEE edge appearance. Evaluate and inspect boolean results, normals, joints and thickness; successful modifier evaluation is not a visual pass.

## 6. Interior craft and materials

The interiors note provides the room references and known furniture/finish details. Make an object checklist per room before authoring its furnishings. Reproduce visible furniture proportions, placement, wood grain direction, supports, joinery, edging, upholstery seams/piping, bedding folds, lamp shades/stems, brackets, handles, shelves, books and characteristic objects from those references. Include small details according to visibility, not random clutter density.

| Material / assembly | Required treatment |
|---|---|
| Painted concrete/parged surfaces | Observed warm light-ochre appearance; restrained fine surface relief; credible edge rounding and contact; repaired/restored condition. Avoid pure-white generic concrete or exaggerated dirt/cracks. |
| Masonry and natural rock | Separate cut/laid wall stone from geological ledges; actual course proportions, fractured/stratified forms and local color variation; wetness/moss only where plausible and supported. |
| Flagstone | Irregular joint pattern, actual slab scale and boundary continuity; soft reflected highlights appropriate to the particular finish. Trace key visible seams; no evenly tiled cobblestone substitute. |
| Wood/built-ins | Member-specific grain orientation, plywood/veneer edge logic, joinery, subtle finish variation and dimensional construction. Avoid applying one stretched wood image to every face. |
| Painted steel | Actual thin profiles and meeting details; Cherokee-red appearance calibrated across references. Paint is the visible dielectric layer; don't make it uniformly bare metallic. |
| Glass | Finite thickness and correct normals in the master, framing, joints, reflection and transmission checks at corners and through multiple panes. No empty holes or opaque glossy plates substituting for glass. |
| Textiles | Believable thickness, seams, contact deformation and fine weave/sheens. No inflated smooth boxes. Preserve recognizable patterns only where reference/asset use supports them. |
| Kitchen/baths/service fixtures | Use each room's evidence, correct era and measured fit. Model visible sinks, taps, appliances, sanitary fixtures and cabinetry distinctly; never paste a generic contemporary bathroom into every suite. |

Use physically sized photo-derived PBR assets selectively where they resemble the actual material. [Poly Haven's CC0 assets](https://polyhaven.com/license) are useful raw inputs, not proof that a downloaded stone matches Fallingwater. Keep color images in the correct color space and roughness/normal/height data as Non-Color. Inspect normal orientation, displacement bit depth and physical amplitude. Do not use a photograph containing sunlight/shadows as an uncorrected albedo map.

Distribute detail across shape, roughness, color and contact. High-frequency noise alone does not look like craftsmanship. Control UV density according to closest intended viewing distance; increase hero texture resolution selectively, retain aspect ratio, and do not destructively resize all source images. Use final-output 100% crops to judge whether the detail resolves naturally.

## 7. Water, terrain and late-summer woodland

The ground is a shaped geological site, not a flat plane with scattered spheres. Reconstruct the major rock shelves, waterfall lips and drops, under-house contact, streambed/banks and bridge relationship from multiple views before decorating. The verified PASDA **22001480PAS bare-earth DEM** archive is already downloaded under `references/terrain/` (44.6 MB ZIP; source/CRC/hash manifest alongside). It provides approximately **0.762 m cells** for broader terrain. Its horizontal system is NAD83(2011) Pennsylvania South FIPS 3702 in **US survey feet**, with NAVD88/GEOID12b elevations also in US survey feet. Validate the actual GeoTIFF and transform/register it deliberately: one US survey foot is `1200/3937` metres, distinct from architectural feet. Retain a local modeling origin and solve the relationship to HABS's relative datums. This 2019–2020 aerial terrain cannot establish individual overhangs, waterfall surfaces or current rock microdetail. [Exact source and metadata](research/architecture-agent.md).

Water needs depth, credible edge/shore transitions, flow direction, reflection/transmission, surface structure and aerated impact zones. Shape the falling sheets/filaments to the real ledges and outflow. Use controlled foam and localized spray; avoid a solid white ribbon, uniformly opaque foam, ocean waves in a narrow stream, or a blue mirror across the whole site. Wet rock should have coordinated reflectance/darkening. Match water's photographic appearance to shutter duration; do not model long-exposure blur as solid geometry.

Start with a believable looping interactive water treatment using geometry and flow-aligned animated shading. Test whether a localized fluid simulation improves the needed views before committing to its cache cost. If used, resolve obstacles and physical scale in a small pilot, then cache on the external SSD with a measured storage budget. Do not begin a massive full-site simulation as a substitute for art direction.

Use site-appropriate trees and understory from the landscape research: layered crowns, real trunks and branching, leaf silhouettes, canopy gaps, ground litter, exposed soil and restrained moss. Preserve the hero views and natural spatial organization without simply deleting all obstructing woodland. Late-summer foliage must be full and coherent across the site; archive leaf-off photos support geometry, not the selected season. Avoid unsupported autumn colors or out-of-season mass flowering.

Keep repeated assets instanced, use several credible variants and constrained distributions, and preserve real geometry near the route. Farther vegetation may use tested LOD. A model that looks good only because shallow depth of field hides the forest fails the exterior exploration requirement.

## 8. Lighting, color and render profiles

Use one consistent architectural master with two tested profiles:

- **Photo / Cycles:** final photographic stills, settled-view inspection and any later showcase render. Use Metal GPU compute. Do not prescribe CUDA/OptiX, GPU OSL or GPU Path Guiding for this Mac.
- **Explore / EEVEE:** responsive exterior orbit and continuous room traversal. Bake/test room-scale indirect lighting and necessary reflection probes. Preserve the architecture and recognizable materials; document renderer-specific compromises.

EEVEE and converged Cycles are not identical. Do not claim real-time path-traced quality merely because both exist in one file. Reference-match the important views between profiles, especially glass corners, deep interiors, water and reflections as objects leave the screen. [Version-specific technical sources and limitations](research/blender-realism-agent.md).

First establish a neutral reference/diagnostic setup to validate material response and geometry. Then create a beautiful late-summer presentation: coherent sky and sun, believable forest occlusion, luminous terrace edges, deep but readable overhangs and rooms, warm actual interior fixtures, and restrained reflections from water/ground. Favor a carefully balanced photographic scene over theatrical orange grading or uniform fill lights.

Derive direction and shadows from the registered site orientation and a documented sun/sky scenario. Use an unclipped HDR environment or the tested 5.1 sky model; avoid double-counting the sun. The 5.1 sky/property names differ from older tutorials, so inspect RNA rather than hard-coding old enums. EEVEE may require an explicit matching Sun even when a Cycles sky provides sun-disc lighting.

Fix the working color space early, using a documented interoperable baseline such as Linear Rec.709. Begin with AgX and explicit exposure/white balance/look. Distinguish working space from display transform. Save scene-linear EXR masters where useful and inspect the delivered SDR images as sRGB, rather than relying on a wide-gamut display to make oversaturated output look attractive.

Use samples/adaptive noise thresholds as tested starting points, not magic quality guarantees. The technical note suggests preview 64–128 samples and final trials in the 512–2048 range according to convergence. Verify denoising against undenoised crops so it does not erase stone, wood grain, mullions, foliage or fabric. Test transmission/transparent bounce limits using deep multi-pane views. Fix bad geometry/materials before clamping away water/glass highlights.

Benchmark four representative cases before expensive output: hero exterior, deepest interior, glass/material close-up, and water/vegetation. Record device, resolution, memory, preparation time, total frame time and disk cost. Re-bake probes after relevant changes. Add detail according to visible contribution and measured performance, not arbitrary global polygon/sample targets.

## 9. A usable exterior and interior exploration experience

Deliver a native Blender **Explore** workspace opening at an intentional exterior viewpoint, in the correct rendered profile, with presentation overlays/gizmos hidden. Provide a small obvious Fallingwater panel or equivalent controls for:

1. **Exterior overview/orbit** and **return home**.
2. **Start free flight**, with mouse look and familiar movement keys.
3. **Room/terrace bookmarks**, named in plain language and mapped to the source room IDs.
4. **Explore / Photo quality** selection, with clear expectations that Photo can take time to converge.
5. A concise, visible control legend and a reliable way to release navigation and return to editing.

Native Blender Fly/Walk may implement movement if it passes actual testing. Verify the installed keymap, mouse-look, vertical movement, speed/precision controls, start/reset and Escape behavior; do not just copy an old shortcut list. A reasonable starting eye height is around 1.6 m, adjustable for the actual low architecture. No numpad should be required for basic use.

The normal **Start exploring** action must also start/resume the intended water animation. Native Fly/Walk alone does not advance the timeline. Verify moving water while the user is freely navigating, and verify the same behavior after a fresh reopen; do not require a hidden console command or a separate undocumented playback step. Keep animation updates on the supported Blender execution path.

Free flight must allow continuous six-degree-of-freedom exploration, including exterior to interior through genuine openings. Provide slow movement for tight rooms and faster travel outside. If adding a walking/collision mode, test a volume/capsule against doors, stairs, headroom and furniture; a single camera ray is not robust collision. Keep explicit free flight available and do not alter the building to hide collision problems.

Maintain independent cameras for source matching, user exploration and still output. Room bookmarks must place the user in clear space facing meaningful content. Reaching a doorway must not reveal missing ceilings, backfaces or holes. The traversable connection between the main and guest houses must align physically.

A web viewer is **optional** and must not delay or replace the native Blender deliverable. If later requested, derive an optimized glTF/GLB version with separately tested material baking, navigation and collision. Fixed 360° panorama hops or a prerecorded movie alone do not satisfy free flight through actual geometry.

## 10. Adopt useful open-source work selectively

Read the audited Skills.sh/GitHub section in the technical note. It includes timestamped install/star counts and inspected source snapshots. Popularity is a discovery signal, not proof of correctness.

Use the useful archviz/material/QA organization from `arjun988/blender-skills` and multiview/landmark repair practices from `RobLe3/cc-blender-skill`, adapted to this evidence hierarchy. Do not inherit unrelated workflow instructions or bulk install every skill. The audit found stale renderer/export enums and damaging baking/resizing recipes in otherwise popular examples; preserve source materials and validate scripts against installed 5.1.2.

Optional targeted tools: Trimesh for independent mesh checks; fSpy for a camera-match pilot; existing Blosm or BlenderGIS for verified terrain data; Sverchok for a genuinely simpler parametric assembly. Bonsai/IFC or COLMAP become useful only if appropriate source data exists. Keep plain `bpy`/manual measurement fallbacks. Do not use generative image-to-3D or low-poly catalog assets as final substitutes for the documented building or distinctive furnishings.

Record each adopted version/commit/license, its purpose and a small successful test. No dependency merits disrupting the project or degrading fidelity merely to say it was used.

## 11. Build milestones and internal quality gates

These gates are work checks, not requests for user approval. Continue autonomously through them, repair failures, and keep the current status in `STATUS.md`. The user has asked for sustained execution and QA.

| Stage | Work | Evidence needed to advance |
|---|---|---|
| A. Evidence lock and preflight | Read/inspect archive, expand rooms, establish era/conflicts, verify control/storage, calibrate plans and cross-building datum | Room/source/dimension ledgers; environment record; no unresolved gross geometry contradiction |
| B. Entire architectural shell | Trace every floor, façade, terrace, connection, service space, roof and major site rock/stream form | Orthographic overlays and multi-view clay renders; correct routes/scale; all spaces represented |
| C. Representative finished slice | Fully detail a living/hearth/window/terrace area with adjacent masonry and water/landscape context | One exterior, interior and close-up pass in both engines; no blobs, wrong scale or fake glass; initial performance record |
| D. Full interior/exterior completion | Apply proven craft to every room and façade, all observed furniture/fixtures, landscape and water | Every room's implementation complete; inferred details separately labeled with reasons/confidence; no hidden proxy rooms |
| E. Lighting and exploration | Final light balance, color management, probes, controls, bookmarks, performance work | Full connected interactive traversal, all controls tested, renderer comparisons, measured timing |
| F. Independent visual review and repair | Compare against sources, inspect contact sheets/crops, record and fix defects | All critical/major defects resolved and affected views rechecked; final QA report |
| G. Packaging and clean reopen | Portable `.blend`/assets/scripts, stills, launch/control guide and known limitations | Fresh-process reopen from delivery location; missing-file scan clean; navigation works; all delivered links/files verified |

User-authorized agents may independently review architecture, interiors, materials and QA images. Give them bounded assignments and source access. The coordinator owns integration and the one live scene writer. A reviewer should name concrete defects and source discrepancies, not merely score whether the scene feels impressive.

## 12. Acceptance tests and definition of done

The numeric targets below are project checks, **not claims of professional survey accuracy or universal photorealism**. Record actual results and uncertainty. Do not silently relax a target to declare completion.

### Fidelity and geometry

- Every inventory item has a model/review state; **zero silently omitted rooms or unexplained final proxies**.
- Explicit source dimensions reproduce their transcribed values within **5 mm or 0.1%, whichever is larger**, unless source uncertainty is greater. This measures digital transcription, not the real building's current accuracy. Raster-derived values retain their own calibration uncertainty.
- Save orthographic overlays for every main/guest floor, the four main façades, available guest façades and coordinated sections. Check heights, cantilever extents, wall/opening positions and stair relationships.
- Register at least **eight independent exterior reference views**, covering classic southwest, east bridge/entry, north/rear, west glazing/masonry, roof/terrace relationships and guest canopy/pool. Do not distort geometry to match one lens. For unambiguous structural landmarks aim for median reprojection error ≤1% of image diagonal, reporting exceptions and lens uncertainty.
- Check evaluated geometry for accidental holes, inverted architectural normals, floating furnishings, z-fighting, broken booleans, wrong material assignments and unintended intersections. Apply watertightness checks to intended solids, not indiscriminately to leaves/open environmental meshes.

### Visual quality

- Inspect each exterior direction, terrace underside, roof, entry/bridge, rock junction, waterfall and pool.
- For **every enclosed room**, capture at least doorway-in and reverse views, plus enough additional views to inspect every boundary and focal object. Closets/service spaces may use compact inspections; they may not go unchecked. Use a 360° interactive look as a complement to stills.
- Review final-size images and 100% crops of stone joints, concrete edge highlights, wood grain/edges, glass corners, furnishings, lamps, fabrics, foliage and water. Reject obvious tiling, plastic response, overblown displacement, faceting where inappropriate, denoising smears and repeated identical plant silhouettes.
- Compare neutral and presentation lighting. Reject unexplained light leaks, clipped architectural detail, uniform room illumination, black/opaque glass failures and excessive grading or blur used to disguise modeling problems.
- Every defect has an ID, room/object, camera/reference, severity, corrective action and recheck image. **Zero unresolved critical or major defects** at delivery. Minor residual limitations must be specific and disclosed.

### Interaction and performance

- Traverse exterior → entry → all main rooms/terraces/levels → connecting bridge/walkway → guest rooms/pool → upper staff spaces, and separately inspect the service basements. Test difficult doors/stairs in both directions.
- Test orbit, look, free-flight movement, vertical travel, speeds, every bookmark, release/Escape, return home and profile switching on the saved file. No forced wall-crossing to access a room; free flight may intentionally pass through geometry when the user chooses.
- Review actual continuous motion for water-loop seams, foliage shimmer, shadow/reflection pops, light-probe leakage and exposure transitions. Attractive selected stills are insufficient.
- Initial Explore target on this Mac: **at least 30 FPS median at a documented 1920×1080 viewport, with 95th-percentile frame time ≤50 ms** after warm-up on representative routes. Measure actual presented/rendered frames with a suitable method; timeline playback rate or a Python callback frequency alone is not proof. If profiling requires another tool, state how it measures the result. Optimize instancing/LOD/probes/textures first; report genuine limitations instead of quietly compromising the house.
- Native 4K is a quality aspiration, not an unmeasured real-time promise. Preserve full-quality Cycles output while optimizing the Explore derivative.

### Final outputs

1. **Editable Blender master** with complete scene, named collections, intact materials and references to required assets.
2. **Working Explore experience**, intentional start view, room bookmarks and local launcher/control guide.
3. **Final photographic stills**: at minimum classic waterfall exterior, alternate exterior/entry, guest-house/pool context, living/hearth, one adult suite, third-floor study and one material close-up. Render selected hero images at **3840×2160 or equivalent approximately 4K framing**; use source-appropriate compositions without extreme wide-angle distortion.
4. **Comprehensive QA evidence**, including every-room review imagery, plan/elevation overlays, source-match images, route/control results, measured performance and defect resolution.
5. **Reproducible source/data and documentation**: stage scripts, parameter and room/source ledgers, dependency/asset manifest, `STATUS.md`, `QA_REPORT.md`, `KNOWN_LIMITATIONS.md`, `HOW_TO_EXPLORE.md` and workspace `DELIVERY.md` with verified absolute paths.
6. **Fresh-process delivery check** from the actual final directory, confirming no missing linked images/libraries/caches, correct startup presentation and working navigation.

A polished prerecorded flythrough may be an additional output after core completion, but is not required to replace user-controlled movement. If produced, test a low-cost motion preview before rendering a resumable sequence; do not commit to a long 4K film without measuring cost and storage.

### Completion discipline

Do not claim “exact to every detail,” “scan accurate,” “photorealistic at every viewpoint” or “fully QA'd” beyond actual evidence. The public archive leaves some concealed/current service details unresolved. Document those honestly while delivering the strongest coherent reconstruction possible.

Do not stop because the work is extensive, a first render looks plausible, a nominal sample count was reached, or an add-on failed. Inspect, compare, repair and preserve progress. If genuinely blocked on an inaccessible essential input, isolate the gap, continue independent work, and state precisely what cannot be verified. The final response must identify real delivered files, actual tested behavior and material remaining limitations. Only mark an execution goal complete when all required work and verification are finished.