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You are such a gigantic troll But I'll bump on it still, and give some nerdy details. The collisions between units are not indeed like solid bodies that are impossible to overlap, even with this PR, this will remain true for most units. It's more a spring-like push that tries to make units keep distance to each others. This pushing just use a distance-to-center repulsion force. What's introduced here for boats and elephants is a different stronger pushing and that actually take the unit's shape into account. This is why on the video you see that the hulls act like actual solid bodies. However simulating this, is ~x1.5 time costlier then the simple radial spring pushing. So because that, for small units, the difference in visible behavior would be minor, better go with the simple pushing, and use the better one only for big units that get the most benefits from it. A fun fact is that before this PR, all units were treated the same, so you did had still this radial-pushing for boats (the collisions were spring-like and only a small circle at the center of the boat was even acting as the hitbox) but it was still much bigger then for, say infantry. To detect if units were colliding, the map had a grid that allowed each unit to search a limited area where it might be actually colliding with other units. This grid size had to be proportional to the largest pushing unit of the game : boats - who's pushing effects where questionable anyway. Even if you played on mainland map with no ships whatsoever, the grid was sized to work for boats too. And your unit had to check their distance with much more other units they needed to. So you can say that the lag you experience on mainland, was partially due to ships. This along a few other optimizations with the pushing and more resilient obstruction handling, make the PR a performance improvement for common scenarios (yey!).

Hi, i closed your PRs as you didn't reply for some months. Feel free to reopen them. Nice that you work on this. I also had plans to use AI to improve the Petra. (Not to integrate it but to use it to see where Petra is bad at.) Integrating it that much goes (for me) against the free software philosophy. Every code should be possible to understand. You want the AI to choose a strategy. But you also want the AI to say when to end an attack (fall back) and how a hero should fight. Thous seem pretty different tasks. I think it's bad to solve both with the same system. Currently there are starting-strategies witch are chosen from. It would be good when you take a look there. Maybe you can extend that. The model you choose takes language as "state". Yes it can be json formated and yes it's multilingual but i'm not sure it understands something like {"type":"repair","entities":[177],"target":4030,"autocontinue":true,"queued":false,"pushFront":false,"formation":"special/formations/null"} Why? There has recently been a PR wanting to do a similar thing for Petra. As i remember it the conclusion was to not continue the plan for now. I don't think that it is possible to do it in a mod.

This seems to now be used for the Gaul and Briton villagers. Not sure how accurate it is in that more lower status role (in any case, the villagers might work better as freemen/commoners. With the servants/slaves being portrayed by another type of villager once implemented).

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happened on 22/09/2026 at 12:01 Paris Time

Hi all, I'm Josue (josue on Gitea), a fairly new contributor. I want to share a project I'm about to start, get your feedback before I write code, and later hand you a fork to test and pick apart. The itch Petra is a solid executor. It gathers, builds, places, trains and fights well. But it plays the same linear game on every map, against every opponent: gather, age up, train, attack the nearest Civic Center, repeat. It doesn't use terrain, it doesn't read you, and difficulty is mostly a handicap (gather rate ×0.42 on Sandbox up to ×1.56 on Very Hard, plus some caps). Meanwhile the game ships 51 historical heroes across 15 civilizations: Hannibal, Alexander, Vercingetorix, Leonidas, Fabius Cunctator, Viriathus, Themistocles... and the AI never fights like any of them. Petra's Leonidas doesn't hold a pass. Petra's Fabius doesn't delay. Nobody builds Alesia. The idea https://gitea.wildfiregames.com/josue/0ad/src/branch/strategos/mvp1/docs/strategos Split the bot into hands and head. Hands stay Petra: economy, building placement, gathering, queues, trade and garrison mechanics, the actual battle. The head is new: a small strategy layer that picks a stratagem: wall the choke by the river and wait; build a trade network; garrison the towers along the enemy's approach; strike their army while it's strung out in a pass; fall back. A stratagem enters Petra through one door (Headquarters), which hands it to the manager that already knows how to execute it. The ambush and the Persian trade network go through the same channel. Who picks the stratagem? We write the doctrine, a model judges. Civ doctrine: read from the civ bonuses that already exist as data. Romans fortify, Carthage goes to the sea and to elephants, Persians trade, Spartans hold ground. Hero archetypes: 5–6 playbooks mapped to the heroes: siege builder, ambusher, hammer and anvil, hold the pass, delayer, naval raider. Stages triggered by the game, not the clock: early game follows the civ doctrine; mid game picks a hero and runs their playbook (hero dies → next hero); when heroes run out the AI goes defensive: commerce and fortification. Opponent model: is the other player rushing, booming or turtling? Where is their army heading? Are they weak at sea? This is what changes every game, and it's what Petra has never had. The model doesn't invent strategy. It answers typed questions ("hold, strike or fall back?", "rush, boom or turtle?") with probabilities. That's a classification job, which is why a small model can do it. Free and open, by design The target model is Laya (convaiinnovations/laya on Hugging Face): Apache 2.0, 421M parameters, a classifier that answers typed questions and runs on a CPU (the model card says roughly 200–450 ms per question on CPU; I haven't measured it yet). Optional download (~650 MB). Without it you get plain Petra; nothing changes. No account, no API key, no network, no cost. Multiplayer-safe: only the host runs the model, and its decisions go out as ordinary network commands. Clients don't need the model, lockstep holds, replays replay. This also sidesteps floating-point differences between platforms. One engine change is needed for it: today the server drops commands sent on behalf of another player unless cheats are on (NetServer.cpp), so the host must be allowed to send this one command type for AI-controlled slots. Single-player is unaffected. Mod first: a strategos mod that overlays only the Petra files it touches. Default Petra stays untouched. An honest note on prototyping: to learn quickly which questions matter, the very first prototype uses a hosted typed-question API (TypeSafe's Jev), called from an external Python script through the existing RL interface. That is developer scaffolding only. It will never ship and players will never need it. Both models take the same question format, so swapping to the local model doesn't change the questions. Performance: what it costs Lag is already the most common complaint, and AI plus pathfinding are big parts of it. Today every AI runs on the simulation thread, on every client, every turn. So this has to be designed not to make it worse: The in-engine part is tiny. Petra reads at most one hint per played turn and hands it to a manager it already runs. I'll measure Petra's turn time (the existing PetraBot bot (player N) profiler section) with and without the mod, and publish the numbers. The target is ≤5% overhead. The model never runs on the simulation thread. At 200–450 ms per question on a CPU, running it inline would freeze the host, and in lockstep that means everyone. So questions are asked every few seconds (not every turn), inference runs on a worker thread, and the answer comes back as a command a few turns later. The engine already has a TODO for exactly this pattern (async AI tasks that return after a fixed number of turns, in CCmpAIManager.cpp), and it lines up with the ongoing threading work (#5874). If that helper gets built, Petra's own heavy analysis could use it too. Only the host pays. Clients run nothing extra. The host pays CPU on a spare core, plus the model's memory (roughly 0.5–1.7 GB depending on quantization; I'll measure and publish it). It won't fix lag. I'm not promising a speedup. At best, stratagems replace some of Petra's per-turn strategic scans with a cached decision; that's a side effect, not the goal. How it relates to existing plans From the Gameplay Feature Status and Game Performance wiki pages: Advanced AI is listed as "partially complete" (#973, #3003). The terrain and threat reading here (choke points, the enemy's approach) overlaps #3003 ("Petra should be aware of dangerous areas"). Anything reusable goes upstream on its own. The naval raider archetype depends on #3002 (Petra using ships for warfare), so it comes later. Directional attack bonuses (flanking) aren't implemented, so "hammer and anvil" can only win through positioning and surrounding, not a flank bonus. I'll keep the playbooks honest about what the game actually rewards. "Ambush" here is AI behavior (hold a choke, strike at the right moment). It's unrelated to the concealment mechanic in #3177. Narrative and strategic campaigns were cut from Part 1. A historically flavored opponent in skirmish is a cheap way to get some of that feeling back. How I'll prove it (before anyone gets excited) MVP of the MVP: one map with clear choke points, one stratagem (ambush at the pass), one question (hold, strike or fall back). Three arms on the same seeds: vanilla Petra ambush + a dumb distance rule ("strike when their army is within N metres") ambush + the model Arm 2 vs 1 measures the stratagem; arm 3 vs 2 measures the model. Before any game, the model has to beat the rule on 50–100 hand-labeled game states. If it can't, I'll post that result here too. Roadmap Phase 0: headless Petra vs Petra harness through the RL interface; determinism checked through replays. Phase 1: the hint channel (a new strategos-hint command → Headquarters dispatch). JS only, no engine changes. Phase 2: choke points extracted from the passability grid. Phase 3: the ambush stratagem in Petra. Phases 4–5: rule arm, labeled dataset, model arm; results posted here. After that: the local model on the host, outside the simulation (optional ONNX Runtime dependency, off by default), the small network change above, then more stratagems, civ doctrines, hero playbooks, the opponent model. What I'll share, and what I'm asking I'll share: Everything in my fork, https://gitea.wildfiregames.com/josue/0ad (branch strategos/mvp1): code, match results, replays and the labeled dataset, for anyone to test, reproduce or tear apart. Fixes, as normal PRs, for the RL-interface bugs I run into along the way. #7854 and #7628 look like the first ones I'll hit. I'm asking for feedback from: Petra maintainers: is a single "stratagem hint" entry point in Headquarters acceptable, or would you prefer a different hook? Engine folks: what do you think of an optional ONNX Runtime dependency behind a build flag, off by default? Players and history nerds: which hero should fight how? Which maps have good passes? Everyone: is this a direction the project would consider upstream one day, or should it live as a mod? Either is fine with me. Disclosure: I drafted this post with help from an AI assistant (Claude). The plan and the decisions are mine, and any code will go through the normal review process.

Already ships not going through each other is an astronomical improvement (although realistically, for the more direct impacts the ram would perforate the other ship and reversing would be needed to separate them). I hope the same could be implemented for land units, making their movements more natural and their tactics more relevant.

Screencast+from+2026-09-22+02-47-35.webm Screencast+from+2026-09-22+02-49-43(1).webm Better? Also another demo about cavalry movement now : Screencast+from+2026-09-22+02-53-38.webm

Having people who can compile is important for testing many things. I can help you with that if you want to do it some day

My favorite too Hopefully it can be a good starting point to make naval battles very different then land battles. Right.

Too bad it's not possible to make a mod, unfortunately I don't have it compiled. I like what I see in the videos. The ship's movement looks really natural. The timing in the other two videos might be not 100 percent on point (on the elephant attack too late, on the catapult impact too early?). I think it's nice and I wanna encourage anyone who is able to test it

I haven't even looked at the Romans in vanilla yet

Thanks @Asher! This is great to hear! (read ) Just tried to convert some older maps from the forum (the LegendofMali worked mostly!) but some are just too old and I need to investigate how to still use them.

Seems to work , @Grautvornix

Unfortunately it's mainly modifications to the game engine itself, meaning it's not possible to wrap into a mod. But I can help out by providing a couple of demo videos for you : (I had to compress the videos) Screencast+from+2026-09-21+22-14-52.webm Screencast+from+2026-09-21+22-13-08.webm Screencast+from+2026-09-21+22-11-19.webm For testing you will need to know how to compile the game. Which makes things difficult I'm aware.

I'm excited to hear this is going forward! Is there a way you could provide a mod for easy testing purposes if it's not too much work? That would be awesome.

Sure, but as with many things, that's just an abstraction. No battle represents an actual battle, but a whole conflict, at least in a game like this, and how things are represented is always a decision to be made. A possibility could be for corpses to be robbed to get Loot, and after that for them to disappear fast. This would naturally be more safely done after the end of battles. But I don't know if this has been discussed, nor it seems a priority to me, compared with so many other things. Maybe I'd go 75% for stone and metal, and 50% for wood (or 50% 25% if from a gameplay point of view those are too much): easier to remember, takes into account stone and metal are highly reusable, and the process has to be worth it (this considering they are unbuilt/unproduced as I mentioned, which is part of the balance when compared to just deleting them). Actually, this way to get stone and metal should be an important one (at least realistically), not even Catholic Popes would eventually resist melting Roman bronze statues to make cannons, for example.

@Thalatta You are right - will remove that constraint (also use captured buildings as a quarry). Will also change the refunding stone and metal (50% each) wood (30%). While modifying the mod, I changed the "delete" function of everything: a unit being deleted (killed by its "owner") looses health over time (10s) until it dies (same es when being attacked), as well as any structure/siege/ships being deleted. Here is the latest version 1.4.0 with that logic (I know there is still a way to go). recover-resources.zip README.md

Updated to 1.3.0 (see top of this thread) Extended editing capability Analyze tab lists also treasures and relics if any Re-arranged section on the analyze and edit tabs fo rimproved readability.

Sure, but I just find it funny and it never made sense that you can earn loot in a battle in which no one survives to bring home anything.

Yes, which is why I have told you to at least look at the mod wether it be download and the structure tree, or just on github its self.

Do you also have triarii units? I guess that could be useful not to just lose spearmen.

The game does have "ruins" in many scenarios, which provide stone. The problem would be to take care of a more seamless transition between all kinds of buildings and their corresponding ruins. Maybe later on all these concepts could be unified in a coherent framework, but right now unbuilding/unproducing seems the simplest way. The game already includes Loot from killed units. Realistically, to the victor should belong the spoils, but as you say, in a game like this it's hard to determine when a battle ends, thus individual opportunism is what's accounted for.

I would find it "logistically" more "realistic" and tactically more "interesting" if destroyed buildings, no matter if self-destructed or the enemy's, would turn into "mines" containing the resources which have to be explicitly gathered and brought to one's storehouses. Also a battlefield could turn into "mines" with the "loot", like scouring the field after the battle looking for usable stuff, although it's hard to determine when a battle "ends". Would change balancing heavily against rushers/attackers in far away foreign territory though. Instead of "mines", the resources could also turn into those bonus-/treasure-item-like things, although those don't have to be brought to one's storehouses.