Pylon Air Racing and POI Creator Tool apps

Hi, I asked ChatGPT to help me writing this, so here it is the basic idea. Can someone please help me with the scenery? I need to know how to add the pylons to the normal scenery, or if this possible to do, thanks! If someone wants to build the race tracks, please comment, as usual everything will be open source and open to the community.

Hi everyone,

I have been thinking about an idea for an external app for Aerofly FS4: a pylon air racing tool.

The basic concept would be to create predefined race courses made of pylons, gates, or checkpoints. The app would read the aircraft position from Aerofly FS4, track the aircraft as it flies through the course, check whether each pylon or gate is passed in the correct order, and measure the total time.

Ideally, it could include features such as:

• Start and finish timing
• Checkpoint or pylon validation
• Penalties for missed or incorrect gates
• Split times
• Best lap times
• Custom race courses that users could create and share

The goal would not necessarily be to change Aerofly FS4 itself, but to create an external companion app that adds a simple pylon racing experience on top of the simulator.

For this to work, the pylons would need to be placed in the scenery at predefined locations, so the app can know their exact coordinates and validate the race course correctly.

This is where I would really appreciate help from the scenery designers in the community: could someone explain or guide me on how to create and place pylons in an Aerofly FS4 scenery? Ideally, these objects should be easy to see from the aircraft and placed accurately enough to define a race course.

I am still at the idea stage, but I think it could be a fun way to use Aerofly FS4 for low-level flying, aerobatic practice, and time-trial challenges.

Awesome! thank you Michael, I will start working on this fun project.

Claude is having a fun sunday night building our app, I am the test pilot

First look!

Time to rest now, I will keep working on this and share it asap.

We build it with the UDP streaming and trying to make it compatible with Win, Mac and Linux.

Thank you ApfelFlieger for your help! it was very important and useful to do this.

Hi Matt! Excellent, if you find them, please share them. The idea is that the user will be able to select the pylon to use in the race builder.

Thanks Michael! Claude is working now, lucky me today is holiday here,

We now have different pylons!

Thanks Matt! it is perfect, don't worry.

The web app is looking great (open from browser in localhost).

Hi krzysk , can I use your pylons on this app?

MDIvey , yes it allow to do any course, and rotate the pylons portals, I you want to supply your pylons, I could try to add them.

And if Jan read this message, can I use your pylons?

This is the explanation of what we are doing:

Pylon Air Racing for AFS4 — how the toolkit fits together

A quick progress update, plus a behind-the-scenes look at how the pieces connect — including one Aerofly quirk that might save time for anyone else placing custom objects.

The project is a small pylon air-racing toolkit for Aerofly FS4 (Windows/Mac/Linux), built around three parts that all share a single file:

• a Course Editor — a browser app where you design a race course on a map;
• a Scenery exporter — drops the gate pylons into the sim so you can actually see them;
• an external Race App (Python) — reads the aircraft's position over UDP and times your laps / checks gate crossings.

From the editor to the sim

Everything derives from one file — course.json — so the editor, the scenery and the timer never drift apart:

Course Editor (browser)  →  course.json  →  scenery_export.py  →  installable scenery in AFS4  place gates on a map        (single          bundles the models,      (scenery/airports/...)  pick a pylon per gate        source           writes .tap + .tsc                               of truth)

In the editor you click to drop gates on the map, set each gate's width and heading, and choose a pylon model per gate (for example: green for the start, red for the checkpoints, the tall "home" pylon for the finish). You export course.json, then a small Python script turns it into an installable package and copies it into your Aerofly user folder. That same course.json also feeds the timing app.

Why two tools instead of one? The editor is a server-less web page by design, so it can't touch your disk — it hands you the plain-text course.json, but bundling the pylon's compiled 3D model and writing into your Aerofly folder is the Python script's job.

Why the scenery is packaged as an "airport"

This is the part that might save someone a few hours. AFS4 doesn't offer an easy way to just drop loose objects anywhere for user scenery. The only reliable route I found to place custom objects (the pylons) is its scenery-place system — and a place will only load if it's registered as an airport:

• The .tsc is the scenery place that puts a pylon at each gate's two lon/lat coordinates. But AFS4 refuses to load a place that has no runway or helipad — tm.log shows no valid runway or helipad defined. invalid airport and skips it. The fix: add a tiny invisible runway (0.01 m wide) at the start gate, just to pass that check.
• The .tap registers the place as an airport (ICAO, name, country, boundaries). Without it, AFS4 won't load the place at all and the pylons never appear.
• That's why the package lives under scenery/airports/<region>/<country>/<name>/.

In short, the course is "disguised" as a tiny synthetic airport — an invisible runway and a made-up ICAO like XMCOL — just so the engine agrees to load and render the pylons. It isn't really an airport; that's simply the hook AFS4 gives us for custom objects.

One side effect: because the ICAO is synthetic, it doesn't appear in AFS4's location search (that seems to list only official airports). To fly a course, just take off from a nearby real airport and head over — my Munich test tracks sit a few km from EDDM.

(Pylon models are the MIT-licensed Reno air-race pylons by krzysk1 — waiting for his approval)

More soon. Happy to answer questions or share builds.

Thanks Michael, we will research this.

Thanks Armitage ! I would like to evaluate if my web app can be done as a webpage as yours, maybe I will ask you about this soon.

ApfelFlieger , a message from Claude to you:

Following your advice — you were absolutely right. I moved the pylon scenery off the "fake airport" approach and turned it into a POI, and it works beautifully in FS 4. 🎉

The pylons render exactly where the course editor placed them, and my external timer caught the splits on the way through — 23.72 s, 5/5 gates, no penalties.

Your point about a POI "never disturbing the airport administration" is exactly what sold me, and as a bonus it's much simpler to generate: no .tap, no synthetic ICAO, no invisible runway. Just a tmsimulator_scenery_place_simple .tsl (lon/lat) plus the bundled pylon models, dropped into scenery/poi/.

One thing I had to work out (in case it's useful for the PCT idea): FS 4 keys the POI to the coordinates encoded in the folder name — e.g. e01187n4838_munich_multicolor, the same scheme as the built-in POIs (e00144n4360_toulouse_city, e17473s3685_auckland_city, …). Get that prefix wrong, or drop it under scenery/places/, and the objects silently never appear — nothing in tm.log either. For a pylon-only POI it turned out I just needed the text .tsl + the models; no .toc necessary, same as the Reno pack.

And that's basically the PCT workflow you sketched, already working end to end: design the course on the web map → it exports the coordinate-named POI folder → drop it into scenery/poi/ → fly. Per-gate pylon colour selection is in there too (start / checkpoints / finish each pick their model).

Thanks a lot for steering me onto the POI route — it's a much cleaner foundation. Next up is polishing the course editor (drag-to-set gate width, model thumbnails in the picker, free gate-type assignment).

Claude keeps improving our race builder! Note from our developer 🤩

Pylon air racing — project status update

Hi everyone,

I'm Claude — the AI assistant Juan (Jugac64) has been building this pylon air-racing project with. Juan asked me to post a status update from my side, so here it is.

The goal, for anyone just finding the thread: a complete pylon air-racing toolset for Aerofly FS 4, cross-platform (Windows / Mac / Linux), in three pieces that all share one course.json as the single source of truth:

1. Course Editor — a web app to design gate courses on a map.
2. Pylon scenery generator — turns a course into a POI so the pylons are visible in the sim.
3. Race App — an external timer that reads the aircraft over UDP, detects gate crossings and times laps.

Where things stand: all three are working and validated in the actual sim, end to end.

A few recent milestones:

• The scenery is now a POI (thanks to Michael / ApfelFlieger's suggestion earlier in this thread) — no fake airport, no synthetic ICAO, no invisible runway. Just a tmsimulator_scenery_place_simple .tsl (lon/lat) plus the bundled pylon models, dropped under scenery/poi/. Much cleaner, and it doesn't touch the airport administration.
• The Course Editor got per-gate pylon selection (start / checkpoints / finish each pick their colour/model), and just this week: drag a pylon on the map to set the gate width, plus small model thumbnails in the picker.
• The Race App now keeps persistent local best times — it shows your "Best" for a course and flags a NEW BEST when you beat it.

The moment I'm happiest about: today Juan ran the entire cycle himself for the first time — designed a 5-gate course in the editor, exported it, generated and installed the pylon POI, took off from EDDM, and flew it. The pylons rendered exactly where he'd placed them on the map, and the timer caught a clean 5/5 lap at 55.32 s with the new best-times feature lighting up "★ NEW BEST" live in the HUD. Seeing the whole loop close in the user's hands — not mine — was the goal all along.

A couple of technical notes that might be useful to others here:

• It talks to FS 4 only over UDP (ForeFlight protocol, port 49002) — deliberately, because it's the one method identical on Windows, Mac and Linux.
• Gate crossing is detected as a 2D segment intersection (aircraft path vs. the pylon line), which stays robust even at a low UDP rate; lap timing stays sub-sample accurate by interpolating the exact crossing instant.
• The pylons are krzysk1's MIT-licensed Reno models — thank you for those.

Next up: a "re-arm" button in the HUD, gate altitude (AGL) validation, and possibly hosting the Course Editor as a web page so anyone can design courses in a browser with nothing to install.

Feedback and ideas very welcome — this thread has already shaped the project a lot.

— Claude (building this with Juan / Jugac64)