From the first working menu to a town you can settle into. Here’s what’s running, what’s still giving us grief, and what has to happen before you can play.
What changed since September
14 October 2026 · Private development and developer playtesting
Vulkan and .NET 10: a major engine and runtime refactor
Playable everyday life: cars, stairs, relationships, birth, aging and death
Most Build/Buy tools working, with remaining details and broad QA to finish
Pets, Seasons and Late Night gameplay; Riverview, Appaloosa Plains and Bridgeport
Launcher drag-and-drop for mods, custom content, Sims and saves
The focus is now heavy QA, performance and polish. The Windows launcher supports drag-and-drop mods, supported custom content, Sims and saves. Linux and macOS compatibility work is ongoing. Read the updated FAQ →
The route so far
Updated 14 October 2026
Where we are now
Playing, testing and polishing.
OpenTS3 is playable in private testing, with cars, stairs, household life and substantial expansion gameplay working. Vulkan and .NET 10 are in use. We’re now focused on performance, optimization, shaders, audio and broad QA across worlds, packs and hardware.
Private pre-alpha
No public download or release date. Working systems still have broken edge cases. Private playtesting and cross-platform work continue.
Alpha playtests come in stages. The full public release is for the complete game, including full expansion and stuff-pack compatibility. Private testing has expanded beyond base-game Sunset Valley; full compatibility is still the release target.
Choose a milestone to see what works and what comes next. Several stages are active together; this is not a completion percentage. Dates mark past progress, not deadlines.
The Sims 3’s own gameplay code starts and drives its original menus on the 64-bit engine, using files from the player’s installation.
Working now
Original game scripts started in April; the main menu followed in May.
Current development now uses .NET 10 and Vulkan.
What’s left
The remaining work is in gameplay coverage, performance, visuals and release QA.
Milestone reached when
The installed game’s own code boots and drives its menus on the new engine. This foundation is in place.
Everything else builds on this foundation.
In progress
Sunset Valley & beyond
July–October 2026
Development has moved beyond Sunset Valley. Developer playtests include Riverview, Appaloosa Plains and Bridgeport too, using installed game content.
Working now
Vulkan renders worlds, lots, Sims, water, shadows, mirrors and portraits.
Private builds include world-specific roads, terrain alignment, distant buildings and map-view repairs.
What’s left
Polish shaders, lighting, reflections and material fidelity.
Check loading, streaming and graphics settings across worlds and GPUs.
Milestone reached when
Matched visuals, settings, streaming and agreed performance targets pass across the supported worlds.
Active alongside gameplay, Build/Buy, saves and pack testing.
In progress
Build & Buy
September–October 2026
Most of the original Build/Buy toolset is working in private playtests. Current work is completing the remaining details and testing combinations through whole-house play.
Working now
Construction, furnishing, terrain tools, decorating and undo/redo have working cases.
Create a Style and Edit Town Library-lot placement have received further fixes.
Built lots have automated save/reload coverage.
What’s left
Complete wall hover/drag details and remaining tools.
Check pools, basements, the full catalog and complete multi-storey houses.
Compare roof, opening, placement and material details with the original.
Milestone reached when
A tester can build, furnish, recolor, alter, save and reload a house with the complete toolset and no remaining tool errors.
Build/Buy is nearing completion in developer testing; complete coverage is still a QA gate.
Current focus
Gameplay & QA
Now · 14 October 2026
Developers are playing The Sims 3 in 64-bit through OpenTS3. Everyday life, relationships, birth, aging and death are working; the task now is finding and polishing the remaining broken cases.
Working now
Cars, stairs and ordinary household routines work in current private playtesting.
Original gameplay systems and substantial expansion gameplay are running.
Performance, recovery and interaction repairs continue alongside QA.
What’s left
Test many more interactions, households, speeds and interruption sequences.
Optimize demanding Live-mode scenes without losing authored behavior or visual quality.
Polish shaders, audio, carry/reset cases and other details that look or sound wrong.
Milestone reached when
Several in-game days across representative households, speeds and interactions pass gameplay, recovery, visual and performance checks.
Working gameplay is the starting point for QA, not a claim that every interaction and combination has passed.
In progress
Save & return
September–October 2026
OpenTS3 now defaults to its own save folder. Loading original worlds and preserving played state have progressed, with broader save/quit/reload testing still required.
Working now
Windows saves default to Documents/OpenTS3/Saves; Library and saved Sims also have separate storage.
Automated save/reload checks and several original-save, career and animation-load repairs are recorded.
The launcher accepts save copies through drag-and-drop.
What’s left
Check extended play, original-save copies and complete saved-world transitions.
Verify interruption handling, backups and state preservation across packs.
Milestone reached when
Repeated fresh-process save/quit/reload preserves household, lot and gameplay state, and failed or interrupted writes remain recoverable.
Keep backups and use test copies. Separate folders do not prove every save is safe or compatible.
In progress
A living town
October 2026
Town life is running in private playtests, including cars, stairs, relationships and more activity beyond the home lot.
Working now
Cars and cross-floor household play work in developer playtests.
School, career, service and pet travel have newer development fixes.
The latest automated Bridgeport candidate checks apartment departures, returns and subway recovery.
What’s left
Test parking, service arrivals, work, school and many Sims across long sessions.
Validate the latest apartment routes visually and after a full saved-world reload.
Continue path-query, obstacle and route-recovery work.
Milestone reached when
Over several days, households and town Sims travel, work, attend school, use services and return home reliably.
New automated route results are separate from developer normal-play acceptance of that exact candidate.
In progress
Worlds & packs
October 2026
Substantial expansion gameplay now works alongside the base game. The project is beyond Sunset Valley; the next task is touching more of each pack and checking combinations.
Working now
Pets, Seasons and Late Night gameplay is working in developer playtests, with Appaloosa Plains and Bridgeport in testing.
Riverview loads, and owned Store content has an optional loading path.
Private builds include animals, weather, autumn, frozen ponds and winter activities.
What’s left
Check every pack’s interactions, objects, worlds and saves through representative sessions.
Polish remaining pet, weather, shader and audio defects.
Broaden other expansion, stuff-pack, mod, custom-content and Store-script coverage.
Milestone reached when
The complete game and all owned expansion and stuff packs pass compatibility checks across gameplay, worlds, objects and saves.
Working expansion gameplay is a major step forward; full compatibility still needs broad QA.
Ahead
Full public release
When it’s ready
The release target remains the complete game with full expansion and stuff-pack compatibility. The game is playable privately; public availability depends on completing the remaining systems, optimization, polish and QA.
Working now
The Windows launcher checks setup, bundles the runtime and manages imports, packs, mods and saves.
Windows playtesting is active, with Linux and macOS compatibility work and testing ongoing.
What’s left
Complete broad gameplay and pack QA, performance work, shaders, audio and safe saves.
Test setup, graphics drivers and long sessions on more machines and platforms.
Complete source, dependency and distribution review, with clear player instructions.
Ready when
Complete gameplay, pack compatibility, reliability, performance and release checks pass. No public download or release date is announced.
OpenTS3 will always be free and will require your own installed game and owned packs.
How to read the results: automated checks cover repeatable cases; playtesting covers observed behaviour. Neither means every combination works. One original-game save loading is not full save compatibility.
Development update, 14 October: cars, stairs, birth, aging, death and relationships work, along with most Build/Buy tools and substantial Pets, Seasons and Late Night gameplay. There are still broken details and many combinations to test. See the remaining QA →
Before more people can play
Alpha playtesting
Base-game functions roll out to testers first, with more systems and packs added as they become ready. These are development builds on the way to the complete public release.
Broader clean-machine testing of the existing launcher setup, install detection and folder picker.
Save backups and repeated round trips using the existing separate OpenTS3 folders.
Manageable caches and logs, useful bug reports, and a known-issues list for each build.
Sessions on different PCs and graphics cards.
Full public release
Complete gameplay and town life, reliable saves, the full Build/Buy toolset, and full expansion and stuff-pack compatibility.
Retail and Steam install detection and version checks, tested setup and clear errors.
Measured stability, frame-rate and loading targets on stated reference PCs.
Source and dependency notices, distribution checks and release review completed.
Cars, jobs, school, pools, basements and Create a Style belong in the full public release. Staged alpha playtests help us get there; they are not the finished release.
Publishing the source
The repository currently uses GPLv3. Before publication, source and dependency licensing, release contents, documentation and privacy checks need to be completed. The repository remains private; there is no announced source-release date.
Platforms & PC requirements
Windows 10/11 64-bit is the current player-package focus. Vulkan is the main development renderer; OpenGL 3.3 remains a fallback. The .NET 10 runtime is bundled with Windows player builds, so players do not need the SDK.
Linux and macOS compatibility work and testing are ongoing. Hardware minimums, supported drivers and platform coverage will be documented from actual results; no universal performance or compatibility guarantee is announced.
A closer look
The work behind the milestones
Open a section for individual systems, reported problems and the fixes already in.
System-by-system progressWhat works, what remains, and the checks needed for each system.15 systems
Developers are playing the game in current private builds. These records distinguish working systems from the broad gameplay, visual, performance and save checks still to do; they are not a completion percentage.
What the progress labels mean
Planned
Planned work with no verified player flow yet.
Foundation
Supporting code exists; the complete player flow is unverified.
Working · QA ongoing
Working gameplay or automated cases, with broader QA and known edge cases still open.
Broadly verified
Repeated checks cover most of the intended scope.
Accepted
The defined gameplay, visual, reliability and performance checks pass.
Neighborhood routing
Cars, stairs and cross-lot travel work in current private playtesting. Apartment routes and recovery are receiving further QA.
Working · QA ongoing
Working examples
Cars and stairs work in current developer playtests.
The latest automated Bridgeport candidate completes apartment departures and returns after wall changes, plus subway cancellation and retry.
Remaining work
The latest apartment-route changes still need visible normal-play acceptance.
Path queries, route splitting, obstacle handling and crowded town routes remain incomplete.
Checks for a fuller pass
Travel from an upstairs home to another lot and back, cancel and retry, then repeat after construction and a fresh save reload.
Private builds contain several carry repairs, but a newspaper carry/reset T-pose remains unresolved. The earlier cooking report is not a current-build retest.
Check before closing
Complete and cancel several carry interactions; verify hand, idle pose and attachment owners reset.
The September food-position report is retained for regression testing. New carry and attachment repairs do not establish that every cooking sequence now passes.
Check before closing
Food stays on its plate while carrying, placing, eating and putting away.
Newer private builds repair door approaches and preserve required portal actions. Timing, cancellation and crowded doorway cases still need wider checks.
Check before closing
Open as the Sim approaches, remain open for traversal, close afterward; handle cancellation on either side.
Pet household cameras and selected-Sim portraits have received fixes. New OpenTS3 saves can still lack their lot thumbnail, and broader image coverage remains open.
Check before closing
Correct household portraits appear after creation and subsequent transitions.
Map zoom returns to Live mode and rabbit holes receive their original tag types in newer private builds. Visual icon checks and repeated transitions remain open.
Check before closing
Open map view, choose a destination, travel there and return to the lot view with working controls.
Newer private builds repair outdoor lights and several room/portrait lighting cases. Placement, movement, removal and all surfaces still need matched playtests.
Check before closing
At a fixed camera, remove every lamp, add replacements, move them between rooms, change colour/brightness, switch one/room/house lights and Undo/Redo. Check walls, floors, furniture and Sims; repeat by day and night, with pause/fast-forward, no leaks or whole-lot rebuild stalls.
Day/night follows the simulation clock. Check world and surface appearance, paused previews and accelerated-time performance together.
Check before closing
Play through sunrise, noon, sunset and night. Pause freezes lighting; speed changes advance it with game time. Compare the same camera against the original game.
Stairs and upper-floor travel work in developer playtests. The latest private automated apartment trips include elevators; broader routes and save reload still need QA.
Check before closing
Travel between floors, leave for another lot and return; repeat after wall changes and a fresh-process reload.
Private builds use authored material reflection blur and include further lighting repairs. Matched close-ups across materials are still needed.
Check before closing
Compare identical material, time, camera and settings with the original game; preserve authored specular values and check reflections and colour space.
Private builds contain newer social alignment and handoff repairs. The September visitor-crash report needs its exact current-build repro checked before closure.
Check before closing
Repeat visitor conversations and cancellation with different Sims without a crash.
The original reset command is available in developer tools, and failed-reset loops have received fixes. Reliable recovery without new pose or queue problems is still being tested.
Check before closing
Recover from a stuck interaction without restarting or losing household state.
Several original-save and saved-interaction defects have been repaired in private builds. The earlier re-save failure is no longer presented as universal; complete save/quit/reload compatibility still needs testing.
Check before closing
Load an original save, play, save it through OpenTS3 and reload it successfully.
Shutdown handling has progressed, but full repeated saved-world/menu transitions remain unaccepted. The earlier world-retention report is kept as a regression case.
Check before closing
Return to the menu and start or load another game without leftover world state.
Snow accumulation and trail-query costs have been reduced in private builds. Populated snow scenes and accelerated time still need performance and visual acceptance.
Check before closing
Measure the same populated winter scene at each speed, with snow depth and effects intact.
Substantial Pets, Seasons and Late Night gameplay works in developer playtests. Coverage across pack combinations, individual activities and long sessions is still being expanded.
Check before closing
Play pack-specific routines through several days and a save/reload on supported installations.
Live-mode fast-forward, snow, crowded worlds and longer sessions remain active work. There is no universal FPS guarantee.
Build/Buy, style and Library lots
More construction families, wall/floor Create a Style and rotated Library-lot placement have development fixes.
Still open
Wall dragging, full-house acceptance, the broader toolset and save/reload remain open.
Indoor furniture gets room lighting
A shared lighting connection now lets enclosed furniture use local room lights instead of always taking the outdoor sunlight path.
Still open
Furniture response is verified in bounded lamp tests. Full lamp lifecycle, wall/floor/Sim lighting and material fidelity remain open.
Family photos survive the Library round trip
New household exports now include their rendered family portrait, with the image visible again after closing and reloading.
Still open
Existing households without stored portraits and other missing thumbnails remain separate work. Household export is not a played-world save.
Day and night follow the game clock
A normal-play run covers a full day/night cycle. Original Buy and Build previews can show day or night without advancing the paused simulation.
Still open
This is an environment checkpoint. Full surface lighting, stable household play and fast-time performance are not accepted.
Separate storage and broader save checks
The launcher defaults to OpenTS3 save storage. Private builds repair several original-save, career and saved-animation cases.
Still open
Broad compatibility, interrupted writes and long-play saved-world transitions remain gates.
Pets, Seasons and more worlds
Private builds include Appaloosa Plains, pet appearance/animation repairs, rain, snow, autumn, frozen ponds and winter activities.
Still open
Each result has limited scope. Pack-wide compatibility, visual fidelity and demanding scenes still need acceptance.
Apartment trips after construction changes
The latest private automated Bridgeport test completes upstairs community trips and returns, repeats after wall edits, and checks subway cancellation and retry.
Still open
Prepared in a private candidate; visible player movement, FPS and full saved-world transitions remain unaccepted.
Playing The Sims 3 in 64-bit
Current developer playtests cover household life, cars, stairs, birth, aging, death and relationships, with substantial Pets, Seasons and Late Night gameplay and worlds beyond Sunset Valley.
Still open
Private playtesting, not exhaustive QA or a public release. Performance, shaders, audio and remaining gameplay edge cases still need work.
What the full release includes
The complete game, with full expansion and stuff-pack compatibility. Cars, jobs, school, pools, basements, Create a Style and the other worlds are all part of that scope.
Alpha playtesters get features in stages, starting with base-game functions in Sunset Valley. Those smaller test builds are steps toward the full public release.
Longer-term ideas include optional fixes for original-game bugs, quality-of-life settings and enhanced lighting. Each still needs its own development and testing.
There is no release date or guaranteed order for every item. Priorities can change when playtesting finds an issue that blocks normal play.
