Slot Cars

Slot cars are user-made functional, personalized and unique cars on Roblox that are to be used by the creator inside of private "Slot" maps.
== Description ==
Slot cars have unique visuals and stats/tuning depending on the owner's preference. A functional slot must include a chassis and a car body of any sort, which can either be built with bricks and parts in Studio, using OBJ models imported from other sources, or user-made models imported from 3D graphics software, such as most notable software Blender. Users can make slots for fun or to be sold to other users. Slots can either be shared publicly for other users to use and copy or made for private use as well, depending on the owner and creator of the slot.
== History ==
Slot cars first surfaced the Roblox community around 2009, when Roblox first introduced the VehicleSeat to Roblox Studio. The VehicleSeat was virtually the only control system available on Roblox for some time. Although it featured unrealistic and clunky physics, it was one of the most advanced features of Roblox at the time and helped provide an available chassis for slot creators and Roblox automotive companies. Since OBJ and 3D graphics importing wasn't a feature on Roblox as yet, a majority of cars were built by bricks and parts.
It wasn't until October 9th 2012 when developer Zephyred first released a more advanced chassis family; the OpenChassis. It served as a replacement for VehicleSeat and featured virtually realistic driving physics, a realistic steering radius (rather than a chassis using all four wheels to turn 360 degrees), and other advanced features that made VehicleSeat obsolete.
On May 13, 2014, Roblox released OBJ Exporter. Users could now import and export Roblox models and 3D models to Roblox Studio and any 3D software. At this point, users could finally create and import much more realistic car models.
Fast forward to late 2010s, many advanced chassis were made that rendered the OpenChassis obsolete. However, a most notable chassis that stood out from the rest was A-Chassis 6 (AC6). AC6 was much more advanced than OC and many other chassis and was developed by SecondLogic and his group InSpare. It is the successor of InSpare's previous chassis SS6 and featured much more realistic driving physics and suspension, power output, gear shifting, tuning, and more tuning variety. The AC6 quickly rose to fame and replaced SS6 and OpenChassis, rendering them both obsolete. A few months after the release of AC6.52S2 (Around June 2017), Avxnturador took over lead development of AC6, and later released A-Chassis 6 T (Around December 2017), which included integrated forced induction with assistance from IMeanBiz, as forced induction was formerly achieved through the use of external plugins, AC6T quickly made 6.52S2 obsolete, as communities starting making AC6T mandatory. Almost a year later, the final update for AC6T was released, this being AC6.81T. 
In December 2018, A-Chassis 6 C was released, which introduced a properly functioning clutch, which was developed by DJay500, in April 2019, AC6 C 1.2 was released, which revamped the clutch system, created by IMeanBiz, This update also included a way to revert certain features of your car to older versions of A-Chassis, such as 6.81T and 6C 1.1. In September 2019, AC6 C 1.3 was released, which added many things, it added engine fine-tuning, letting you individually adjust power and torque curves, it also separated turbocharging from supercharging, letting you run both at once, it also added backwards compatibility for the older way of tuning engines, as seen in 6C 1.2, this update also added three different clutch modes, these being Clutch, which is like a regular clutch, Torque Converter, which keeps your RPM up, and CVT, which is moreso just in the name, and a few other things.
In July 2020, A-Chassis 6C 1.4 was released, which was the biggest update done to AC6C to date, this update added tons of things, and also included a new collaborator, LuaInt. Some of the things 1.4 included were new engine tuning, which combined 1.2's curve tuning with 1.3's aspiration tuning, it also overhauled the physics to PSG, which also separated power and brake motors, this update also overhauled the steering completely, utilizing real values, while still keeping the older steering configuration as an option, another thing added was Four wheel steering (4WS) which let the rear wheels turn with (or against) the front wheels, a new differential was also added, which was easier to understand and tune, 1.4 also added Clutch Kick, which multiplied torque if a clutch kick was executed, this was useful to initiate a drift or with going up hills, the update also included Massless support, which eliminated the requirement to keep your part count low, further updates to 1.4 included parking brake bias modification, and some bugfixes.
thumb|A default model of A-Chassis 6C 1.5, showing the suspension geometry
Not too long after, A-Chassis 6 C 1.5 was released on New Years Day 2020, which modified some things chassis-related, such as revised torque delivery and weight calculations, one of the biggest changes that came with this chassis was physical suspension geometry, which gave the tuner complete ability to modify the suspension and how it works by moving parts and modifying the constraints, some plugins were also replaced and standardized, such as sound plugins (engine and induction) and aerodynamics plugin, replacing the older aerodynamics plugin that was very outdated.
AC6 quickly became the standard for slot cars, due to its ease of tuning, realistic physics, wide library of plugins and many more options. As of 10/09/2021, official A-Chassis 6 development was discontinued with only support for issues. The current chassis version is AC6C 1.5. update 2. 
== Construction ==
Construction of a slot car can be both complex and simple, depending on section of construction. Parts such as inserting a car body to the chassis and inserting rims to the chassis wheels can be quite a simple process. However, attempting to put the correct position of parts and meshes, and inserting plugins and scripts can be complex and challenging, especially for beginner slot builders. Instructions to make a perfect slot car can be shown in YouTube channel Flaron's playlist. [Flaron's tutorial is currently considered outdated, no up-to-date slot tutorial exists at this very moment] Constructing a slot car should not include an errors and everything must be checked and proofread. If an error occurs when attempting to build a slot car, the results will be unfavorable to the slot builder and may have to restart to check for and avoid any errors.
== Issues with the slotting system ==
The slotting system is fairly simple, the creator of the slot sends the game owner a link to their model uploaded to Roblox, makes it available to copy (freeing), then unfrees (privates) it when the owner has taken the model. There's one main issue related to this, and it's something that the car community refers to as slot sniping, Slot sniping is the name given to when somebody takes advantage of the slot creator freeing their model for a game owner to take and they take it themselves, after this person has the model, it's very common for the slot creator to not notice that their slot was sniped, which could lead to their slot being leaked by the person who took it without permission.
One way to prevent slot sniping, is to check your Sales of goods tab inside of your My Transactions page after you sell a slot, if you see that someone who isn't the game owner or someone you meant to sell it to has taken it, you do what is known as "Bricking", this consists of overwriting your slot with a Part, to prevent the unwanted individual from using it inside of studio, then you make a new model until you can safely give it to the game owner.
Another known issue is leaking, while this isn't an issue with the system itself, it's more of an issue with game owners not being trustworthy, leaking is the name given to when someone spreads "leaks" somebody's slot without their permission, this can be done by a game owner, or by someone with access to exploits, who copies the map into a file, a very known case of a trust-based leaking situation is Fookooshima, a car community group from around 2018–2019, that had the grand majority of its cars leaked by the owner of the group, Nubcek.
An example of an exploit based leaking is that of Hikaru, more specifically, in its second iteration, what happened there was that a staff member let a shady individual into the map, who then proceeded to use an exploit to steal the map, as well as the cars, the map was not uploaded, but the cars were, around 7 people were directly affected by this.
== Sources ==
https://robloxautomotiveindustry.fandom.com/wiki/OpenChassis
https://roblox-vehicles.fandom.com/wiki/Roblox_vehicles_Wiki
https://www.roblox.com/library/136469836/OpenChassis-3-2-Standard-AWD
https://www.roblox.com/library/426082613/A-Chassis-6-52S2-Kit