July 2023 Update
After a bit of a break, last month I decided to finally complete the alternative short layout for pinwheel - ah I can't seem to just let it lie! This is something that I had sketched out 2 years ago but never found the time or motivation to finish, not least because it means tweaking quite a few tedious things to make it work properly, and also learning how to work a track with two (or more) layouts which I couldn’t be bothered to do last year. Hopefully this short post might help anyone else doing it for the first time. Here is the new track layout map with additional portion shown blue:
Initial decisions.
There were a few existing elements such as grandstands and trackside objects that influenced the location of a new portion of track, but ultimately I wanted to retain the high speed nature of the place so banked the main hairpin that leads onto the straight. Clearly one has to consider the pit entry and making sure to give adequate track before it for cars to position their cars appropriately without causing an AI shunt. The short layout is 2.9km so about half the length of the original (now known as the GP layout) that is 5.6km. For reference, this is about the same as COTA but a little shorter than Spa which is 7km long.
There are three new corners, named respectfully after Amin Taha, Álvaro Siza and David Chipperfield - all architects. I wanted to change the atmosphere of this new section, so decided to create a tunnel to initially form the landscape over the track and somewhere for spectators to view from and access the main grandstand at Bo Bardi hairpin. The new track extension runs under a list trellis/tunnel:
About a year ago,
@maruto took some photos from Trois-Rivières and offered them up to the community, thanks so much for this! These were perfect for the walls in the tunnel:
File structure.
To make things a little easier on my brain, I decided the following when the short layout is loaded:
- The spawns would be replaced entirely as the kn5 file contains sector timing points and a hotlap start point. New kn5 file: “pinspawnExtensionBlender.kn5”.
- A single additional kn5 file “pinextension.kn5” would be added containing new objects to guide the driver.
- Nothing other the original spawn points (now used for the GP layout) is taken away.
With regards the latter, not taking any physical objects
away for the short layout means there is no barrier to the new part of the track even if you load the GP layout - in theory you can drive through the tunnel shortcut, but of course as the spawns are different, you won’t have gone through the second timing point and therefore the lap would not count. It's still quite fun to do though
So there are two model.ini files in the pinwheel folder, with all the kn5 files in there ready to load depending on the layout chosen. Of course you can see the same thing with many tracks in AC. Each layout gets its own folder (named accordingly) which contains unique data and AI subfolders, there is still only one CSP ext_config.ini file, despite the two layouts. Here is the file structure:
The extension.kn5 contains a minimal number of objects that would not make sense in the GP layout – namely new distance markers, signage to direct drivers around the new portion of track, and temporary painted lines. That's all there is in this kn5, taken from Rhino:
AI spline.
Once the new layout is ready to race with the new spawn objects and meshes, it was time to record a new fast_lane and pit_lane.ai. One must start afresh unfortunately, editing the spline even the pit_lane one is a nightmare in kseditor, so it’s just easier to do it again. I usually record my AI lines in a Tatuus just to keep the line smooth.
This however unfortunately means first recording it and then secondly going around in ksEditor tweaking all the anomalies as you go around the new spline - but it is what it is. Simply put some nice music on, start from 0.000, end at 1.000 and it’s done in an hour

Note that usually the anomalies are usually to a set distance (for example, snapping to an edge mesh or something), so you can use the addition values to tweak the left and right splines, stepping through each of the 1826 (in my case) nodes, quickly correcting the offset (see highlight in yellow):
As the new layout uses 5 of the old corners, then with 3 additional new ones, much of the early part of the lap can be copied over in terms of the locations along the fast_lane.ai spline. The first part is simple, divide the length of the original GP layout by the new short one, and then multiply all the positions by this factor. This works for both the cameras and sections, and then its just a case of setting up a few more with the new layout at the end.
Pit boxes.
I can’t emphasise enough, if you’re starting a new track then
make sure to include at least 32 pit boxes if you can. I thought 26 would be more than enough at the start, and wanted to keep a relatively short pitlane to not penalise pitting in the race too harshly, however in practice once people started using Pinwheel in league races I did get some comments saying that 26 is a bit limiting. So in order to get 32 (and not change things drastically in terms of the pit entry) I’ve had to double stack the 6 additional boxes which isn’t ideal – it works as collisions are off in the pit of course, but it grates my soul a little and this image makes me wince! Anyway, what’s done is done:
So in summary, it’s not that complicated to add more layouts, it’s just a bit of a faff and worth thinking about early on before modelling too many objects that might lock you into decisions you regret later. The new shorter layout is fun, much better for racing with road cars and the 32 boxes creates more action in the race – if your CPU allows it, mine only just does : )
You can download 2.0 on racedepartment here:
https://www.racedepartment.com/downloads/pinwheel-circuit.47559/
As always, thanks everyone. Have a good summer.
John.