28.02.2022 Category: Site news
Episode 8: the famous AI cars and Dual Player mode
VRC v3 was launched end of 2004 and until 2006 several updates were released, the last one being version 3.5. For the purpose of this Inside Story I call them all v3. Two of the very special and unique features that were developed and implemented by Todd and Lothar were Dual Player mode and the famous ‘AI cars’.
Dual Player mode
One of the things we most certainly wanted in VRC v3 was the possibility to race against real opponents via network. It is important to keep in mind that at the beginning of the new millennium when we started with the development, the Internet was slow and transmission delays (latency) of half a second were not uncommon. Back then it was popular to bring your computer to a friend's house for a ‘LAN party’ to avoid the slow Internet! Really, hard to imagine now…
Dual player was a simple peer-to-peer concept over LAN, so you could race against another racer who was present at the same local network. Later some smart users of VRC figured out a way to play dual player over the internet using a program called Hamachi.
In just a few years the Internet got faster and faster with lower latency or ‘ping’ and accordingly the last version 3.5 of Virtual RC Racing featured a dual player mode over the Internet. After logging in, the user entered a chat room. In this chat room the user could see the other VRC players who are looking for a run. You could set your preferences for track and class so the other players knew where and what class you like to race. In dual player mode over LAN you could also add AI cars making the session even more exciting, however, in the last update v.3.5 it was also possible when playing online. I will describe these AI cars next.
AI-cars
Version 2.0 and 3.0 of Virtual RC Racing featured “replay opponents”, i.e. opponent cars played back from replay files which were recorded in racing sessions. For Version 3.1. Todd came up with a concept to create ‘virtual’ opponents so you could race against opponent cars who were no raced by other racers but using Artificial Intelligence (AI) to drive the cars around the track and ‘seeing’ your car. It was a very smart system which I will try to explain to you. Todd had created a ‘driving line’ data recording system which used virtual ‘gates’ on the track, not sure how many but probably something like one every meter or so. Todd then drove 20-30 laps and at each ‘gate’ the speed data was recorded and where exactly it passed the gate seen from above. This created a chain of car positions for each lap. Now remember, Todd had no r/c racing background, he learned to drive an r/c car while developing the VRC physics. And he became quite good at it! He had to do such recording sessions for each track and also in 3 racing levels: beginner, sports and expert driver levels. I am not sure if we had modified and spec class cars in those days, if we did, he also had to drive the 2 different cars as well.
Recording all these AI lines was already a lot of work but the real hard work was in developing the artificial intelligence or AI to let the AI cars anticipate on where other cars were driving, to avoid crashes when overtaking or when cars returned to the track after a crash. It surely was a unique and ingenious concept! It was fun and intriguing to just watch the AI cars race each other or race against your car, you could see them slow down and look for an opportunity to overtake. The user was able to adjust the speed of the AI cars for offline practice. This was particularly helpful for beginners as they could adjust the speed of the AI cars to their own skill level.
When we started to work on VRC Pro a few years later the question was if we could continue with the AI cars or should we replace it with something else. Knowing what our future plans were, adding more classes, 1:10 and 1:12 electric on-road, and of course off-road classes, with also the option to drive the tracks in both directions it became clear from the outset that it could not be continued. For each track we would have needed some 30 to 50 of these driving line data sets, just not feasible, what a pity... Hopefully this answers your questions why there are no AI cars in VRC Pro anymore. Instead, we opted to go for multiplayer and replay opponents. I will explain these features in more detail in a later episode when I get to speak about VRC Pro.
I found this comment on the AI cars in v3 on RC Tech that says it all how genius the AI cars were:
‘What was useful about the AI cars is that you could specifically reduce their pace and then slowly speed them up as your knowledge of a specific track increased. It was also a very useful way to learn how to cleanly pass cars.’
In the next episode I will talk about the evolution of the game port adaptor. The USB port, invented around 1996, had become mainstream from 2000 onwards and obviously we had to follow this important technological breakthrough. That’s next.
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