Airport CEO Alpha 26 released

Greetings to you all from San Fransisco and GDC!

We’ve had a few extra hours on our hands today and after carefully assessing the most recent bug reports we’ve decided to now go ahead with the deployment of Alpha 26. It’s been deployed on the experimental branch and will be soaked there for a while, since we did a medium sized change to the way built objects are structured in the scene’s transform but if nothing critical occurs for a larger set of users we will deploy it on the default branch later today or early tomorrow.

Alpha 26 is the first performance update we run for the default branch but, as mentioned earlier, we’re nowhere done with performance. We’ve got several micro optimizations still to do, the full implementation of HPA*, additional data type and structure optimizations for large controlling systems such as the job task system and air traffic control. With the UI sprint officially starting next week, we will with the overhaul remove several performance bottlenecks associated with the UI rendering which in itself is another jab at performance as a whole. As we’ve learnt here on GDC, and something we’ll share with you in the next devlog, Unity themselves are working on a very fundamental game engine change that could have a massively positive impact on performance (but that’ll be way further down the road).

Anyway, here is the full changelog for Alpha 26. Again, it incorporates all issues that have not been deployed to the default branch and consequently those issues that make up the changes between Alpha 25 and Alpha 26.

    Release notes - Airport CEO - Version Alpha 26.0


  • [ACEO-2658] - Vehicles in road queues should adjust to speed of ahead vehicle to mitigate gas and break effect
  • [ACEO-3058] - Implement improved person path finding worker thread
  • [ACEO-3151] - Improve performance when manipulating object by improving data structures
  • [ACEO-3402] - Improve object dependency exception handling for vehicles
  • [ACEO-3458] - Improve object dependency exception handling for persons
  • [ACEO-3513] - Game object transform consolidation to enhance performance when simulating movement of large amounts of persons
  • [ACEO-3515] - Streamline agent movement simulation system to reduce performance impact
  • [ACEO-3516] - Issue with updating walk toggle animation causes performance impact
  • [ACEO-3517] - Slight person game object appearance redeisgn
  • [ACEO-3518] - Improved person animations
  • [ACEO-3521] - Added option (in graphics setting) to disable tree animation to improve performance
  • [ACEO-3522] - Added faster data structures for various system to improve general performance
  • [ACEO-3583] - Enhance object pool validation method for minor performance improvements
  • [ACEO-3587] - Improve object pool scaling logic to enhance performance and memory allocation
  • [ACEO-3600] - Temporarily increase font size of certain panels to accommodate some Retina users
  • [ACEO-3606] - Adjusted some pricing values
  • [ACEO-3641] - Improve appearence of high speed conveyor belt tray
  • [ACEO-3727] - Reduce size of default start world
  • [ACEO-3729] - Removed playing animators on hidden underground belts
  • [ACEO-3730] - Various minor calculation related performance optimizations
  • [ACEO-3735] - Enhanced performance of distance calculation method by roughly four times
  • [ACEO-3750] - Added information about unlocking areas in tutorial


  • [ACEO-2311] - Quickly rotating an object in opposite directions can cause the object to become misaligned with the grid
  • [ACEO-2352] - Building small door in paused mode causes sprite to be incorrectly rotated
  • [ACEO-2853] - Add person usage direction arrows on certain items to mitigate risk of placing wrongly rotated objects
  • [ACEO-3084] - Aircraft can at very few instances get stuck on stand due to a null reference exception
  • [ACEO-3173] - Structure using light handler have their lights become visible prior to structure completion
  • [ACEO-3270] - Trying to CTRL delete active taxiway nodes does not give a warning
  • [ACEO-3294] - Unable To Place Fuel Tank Next To Fuel Depot
  • [ACEO-3310] - Rare issue with stuck service truck caused by dead lock when trying to offload non-hauled baggage
  • [ACEO-3401] - Unbuilt attachable fuel tanks are registered as functional by their parent fuel depot
  • [ACEO-3411] - Persons who get lost due to rezoning do not update their security clearance status correctly resulting in becoming stuck and unable to again pass security
  • [ACEO-3421] - Minor typos
  • [ACEO-3496] - Vehicles claiming to be in a vehicle depot when they are actually not can cause stuck vehicles
  • [ACEO-3507] - Aircraft cannot find holding point if stuck outside map
  • [ACEO-3512] - Issue with person movement system yielding causing a high performance impact
  • [ACEO-3514] - Improper way of handling agent parent transform in relation to simulation causes rendering performance issues
  • [ACEO-3526] - Animation causes head and body to become separated
  • [ACEO-3531] - Unable to build bathroom or baggage areas
  • [ACEO-3536] - Flights won't apear after ATC tower relocation & relocation/creation new stands
  • [ACEO-3539] - Oversized ramp agent driving service truck
  • [ACEO-3553] - Clicking luggage causes loss of left-click functionality for remainder of game session
  • [ACEO-3554] - Error on delivery site missing when game is paused
  • [ACEO-3556] - Left clicking function can occasionally stop working
  • [ACEO-3564] - Delivery object null check causes aviation fuel supply trucks to not correctly execute deliveries
  • [ACEO-3565] - Light poles can be placed outside world
  • [ACEO-3576] - Null reference thrown when deserializing aircraft causes loading process to abort rendering staff and vehicles not to spawn correctly
  • [ACEO-3578] - Skip night feature flights scheduled early mornings can cause passengers to miss their check-in as vehicle spawning and movement is blocked
  • [ACEO-3582] - Push back truck waiting loop with lacking cancellation check may in some very rare instances cause it to stuck
  • [ACEO-3588] - Legacy code for speech bubble displayment causes over-allocation and over-pooling of speech bubbles
  • [ACEO-3602] - Information desks do not generate any job tasks
  • [ACEO-3605] - Click error when selecting cargobay
  • [ACEO-3614] - Baggage handling system disables itself when loading game
  • [ACEO-3615] - Franchise staff does not reappear properly when shift change takes place
  • [ACEO-3616] - Assets carried in front incorrectly positioned on top of person
  • [ACEO-3618] - Contractor hammer tool not spawned correctly if game is saved and loaded prior to contractors getting spawned in world
  • [ACEO-3619] - Earth patches not correctly spawned when contractor is constructing a structure
  • [ACEO-3620] - Contractors ignore demolition cancellation order on certain objects
  • [ACEO-3625] - Sprite material not correctly updated on offloaded baggage causing "bright" baggage shipped around at night
  • [ACEO-3626] - Sprite material not correctly updated when employees spawn tools outside causing "bright" tools to be carried around at night
  • [ACEO-3628] - Minor issue on grid update on area in front of subway entrances causing persons to stuck
  • [ACEO-3629] - Legacy code related to animation culling causes persons to not update their animation state correctly when moving camera resulting in a sitting floating movement
  • [ACEO-3630] - Minor issue with certain conveyor belt items with integrated belts being animated despite time being paused
  • [ACEO-3631] - Rare panel null reference issue when loading asset panel can cause the user interface to become unresponsive
  • [ACEO-3633] - Exaggerated performance null check on fuel depot parking can cause fuel trucks to target zero vector
  • [ACEO-3638] - In certain activities persons fail to recognize that a given path request has failed, resulting in them floating across the terminal through objects and walls
  • [ACEO-3642] - Subway entrance is enabled for transit despite not being fully constructed
  • [ACEO-3655] - Foundation bulldozer not working
  • [ACEO-3658] - Persons leaving the airport can get stuck in a waiting loop if no bus stop is available but subway entrances are
  • [ACEO-3668] - Queueable objects with an incorrect rotational offset on the last queue point causes the game to crash when passengers try to access it
  • [ACEO-3679] - Automatic fuel aviation refueling does not execute properly
  • [ACEO-3690] - Incorrect characters in some airport names
  • [ACEO-3692] - Very heavy performance impact on moving aircraft in tripple speed setting
  • [ACEO-3700] - Large performance impact on system related to passengers getting interaction items (seats, desks, etcetera)
  • [ACEO-3717] - Game can freeze when a person with a certain set of permissions cannot find a nearest walkable node
  • [ACEO-3719] - Incorrect brokenrunway alert text
  • [ACEO-3725] - Large rendering performance impact on conveyor belt related simulation due to incorrect disabling and lack of culling on animators
  • [ACEO-3726] - Noticeable performance impact on path request and grid related methods due to ancient code
  • [ACEO-3731] - Several minor lightning related issues with persons, structures, effects and assets having incorrect material and incorrect illumination at nights
  • [ACEO-3733] - Various minor placement and simulation illumination issues for objects, persons and assets
  • [ACEO-3738] - Stand name not visible
  • [ACEO-3739] - Minor issue with flight time visibility on flight planner
  • [ACEO-3740] - When building boarding desk, walls don't remove by default
  • [ACEO-3743] - When loading a save game from an existing loaded world, path finding breaks down
  • [ACEO-3748] - Employees can get stuck when demolishing an object related to a currently performed job task
  • [ACEO-3749] - Tutorial lack step for expanding areas
  • [ACEO-3752] - Person speech bubbles do not rotate with camera
  • [ACEO-3756] - Occupation point fetching error causes passengers to be unable to interact with desks in food and shop rooms
  • [ACEO-3758] - Poor thread cancellation handling when loading main menu or quitting game from in-game world causes the game to crash
  • [ACEO-3762] - Aircraft can get stuck in rare occasions when taxiway connects via side to runway
  • [ACEO-3765] - Minor queue occupation issue on metal detector passage point causing persons to not respect one-at-a-time principle
  • [ACEO-3766] - Excessive post-desk interaction relocation method in tightly built room areas can cause persons to abort their eating or shopping activity
  • [ACEO-3774] - Transform children structure for built objects causes slight WaitForJobTaskGroup render performance impact

New Feature

  • [ACEO-3579] - Havana airline added
  • [ACEO-3595] - Implement Subway Entrance
  • [ACEO-3597] - Added FPS bound camera speed
  • [ACEO-3598] - Data structure performance improvements
  • [ACEO-3599] - Nearest city and country is now shown in new game location setup
  • [ACEO-3640] - Add two new bus types
  • [ACEO-3643] - Add new bench type
  • [ACEO-3728] - Add ability to unlock areas


  • [ACEO-3057] - Improve game engine simulation and rendering performance

Steam patch notes available here:


Great work guys! Can we expect new content soon ?

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Already heard the elevator music and it’s awesome…

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Good Work!

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The new Unity is going to be awesome. Wonder what developers will have to change :slight_smile:

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Wonder what developers will have to change :slight_smile:

Let’s hope they won’t have to rebuild EVERY single line of code :worried:

True, but from what i’ve read, i’m glad they are making some of the hard needed changes

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True, but from what i’ve read, i’m glad they are making some of the hard needed changes

Ohhh definitely :smiley: Back in days when ACEO was released (I think version was 19.x) game was unplayable. I had 5-10 FPS on a regular airport and I was like “AWWWWW Do I have to buy a new PC with high CPU performance?” But after 25.x experimental updates game become more stable and playable. First time in my life I had 60 FPS on regular airport WOHOW :smiley: And I can’t wait to have 60 FPS on an international airport :wink:


Whoot! That’s a long list of tickets done! :muscle: Impressive! :bowing_man: Good work guys and thanks for the hard work!

Hope you enjoy your stay in the US.

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Yes! New UI is of course main target here but we’ll make sure to implement some other new stuff too.

Yeah, it really is a fundamental change required to keep up with the other game engines but we saw some really cool demos on yesterday’s talks. 350k objects moving with 30 fps (without Burst), grantes, on a 20 core machine… still, just on a regular machine 120k something objects moved with 30 fps.

That’ll probably actually be possible with these changes. We’re gonna start labbing with it as soon as we come back to Sweden!


Just run a test on Klia2 (big airport) and can happily say that the path finding system and speed of passengers/personnel towards gates is running smoothly. :sunglasses: After loading the game it had to catch up from planes that were still delayed, but after that it all ran like a clockwork:

Will keep it running for a while, but looking good for now!


Well I had a chance to test 26.0 and here are bugs I found. Most of them are cosmetic and not game breaking bugs but I don’t know what status you guys want to publish on default branch.

ALL these reports are recorded on Experimental 26.0 with old save started on Exp 25.4.

ACEO-3780 - Flight Planner link on Loading Screen
ACEO-3781 - Guy in middle of road saying “can’t move around terminal” but building crosswalk solves it
ACEO-3782 - People stay on each other at check in desk
ACEO-3784 - Current Season logo on top menu is skidded
ACEO-3785 - Discordant Baggage Belt

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Nice testing the both of you!

Comparing the state of the default branch right now and the experimental, the issues would have to be very significant for it to not be switched over. If any critical issues do occur on the default branch we can always hotfix them too! :slight_smile:

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I still get PAX arriving via subway then departing straight away. This is a new build too. Any help would be good. Thanks and keep up the great work.

I’d still love to be able to zoom out more as well.

Yeah, we have that issue on our backlog. However since it seems to be isolated to your save it isn’t as high up in the issue list as other issues.

We determine what issue to work on next as of issue severity and issue frequency, while the issue is pretty serious its not that frequent. It will get look at, eventually!


At least it is a known issue. Cool. Thanks. I can work with that so no worries.


Alpha 26 is now live on the default branch! Hot fixes to come (probably)! :slight_smile:

Patch notes:


I dont know if this is a bug or a new implemented feature?

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Planes are coded to pull up at random angles

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It should be a bug as in real life this would never happen. The plane is always guided in straight to ensure that the jet way (airbridge) can connect properly and ground vehicles have room.