ACE3 packs realism mechanics into removable Arma 3 modules

Three older mod families folded into one codebase

ACE3 describes itself as a joint effort by the teams behind ACE2, AGM and CSE, all working toward the same goal of improving realism and authenticity in Arma 3. That origin explains a lot about the shape of the project. Instead of one large script file that a user either takes or leaves, the code is split into a set of packed build objects that each cover one area of the simulation.

The concrete problem ACE3 addresses is the usual mod fatigue problem. A squad wants realistic ballistics, medical treatment, weather that all clients agree on, and a captive mechanic, but it does not want an explosives module that conflicts with another mod it already runs, and it does not want to maintain a private fork to get there. ACE3's answer is that almost any included PBO can be removed from the configuration, so a team keeps the components it wants and drops the rest.

The primary language of the repository is SQF, which is the scripting language Arma 3 itself uses, with a Rust extension alongside it for the parts where arithmetic matters more than scripting does. The audience is mission designers and server operators, not only players. The project's own documentation points new users at an installation guide and an information center rather than a one line install command, which tells you the configuration surface is meant to be read.

Removing a PBO is the configuration model, not a fork

The modularity claim deserves a close look because it is the claim that determines your maintenance cost. The project states that the mod is built modularly so that almost any included PBO can be easily removed from the configuration, and that a team can maintain its own tailored version simply by excluding components it does not need or that might conflict with other mods. There is a top level optionals/ directory in the repository alongside addons/, and the presence of a build script at the root, build.bat, with a hemtt.toml file and a .hemtt/ directory, points to a build time mechanism for choosing what goes into the package.

That is a different approach from maintaining a personal fork with edits committed on top of upstream. A fork means every upstream change has to be merged, and every upstream change is a chance to conflict with your local edits. A component list means your customization is a list of what you include, so upstream changes arrive as new components rather than as edits to your code. The project makes this explicit about licensing too: it invites you to maintain your own custom version, provided the changes you make are open to the public in accordance with the GNU General Public License.

Modules also carry their own customization options. The medical system, for example, is described as improved with basic and advanced levels, and mission designers are expected to tune the overall experience. Individual modules, not one global settings file, are where tuning happens. The README does not list the setting names, so if your plan depends on a specific key for the medical level, you have to find that in the component itself.

Ballistics and fire control run in a Rust extension

The repository is not only SQF. The file listing at the root includes ace.dll and ace_x64.dll, an extension/ directory, and a Cargo.toml and Cargo.lock pair. The Cargo manifest defines a workspace with a single member and a release profile tuned for small binary size:

[workspace]
resolver = "2"
members = [
  "extension"
]

[profile.release]
opt-level = "z"
lto = true
codegen-units = 1
strip = true

The feature list ties the extension to specific mechanics. Realistic ballistics and the fire control system are described as calculated in Rust extensions, and the fire control system itself is offered for armored vehicles and helicopters. A dedicated extension is a reasonable choice for trajectory and FCS math, where rounding and frame rate behavior are visible to the player, and the release profile shows the authors were thinking about shipping cost per binary.

A native extension is also a portability constraint. The extension has to be built for the platform your players run, and the presence of both 32 bit and 64 bit DLLs in the repository suggests both are maintained, but the project does not document the build toolchain in the repository listing. If you are a mission designer without a development environment, you are consuming these binaries rather than rebuilding them, which means the workflow the project actually offers you is the prebuilt release.

Systems that all clients have to agree on

Several ACE3 features are network-sensitive by nature, and this is where a simulation mod either behaves or annoys everyone. The project lists proper and consistent network synced weather, which means the weather state is authoritative and shared rather than rolled locally, and wind and weather based ballistics, which means a shot's outcome depends on that same shared state. Advanced missile guidance and laser designation sit in the same family of features, since a designation that differs between two clients produces the kind of desync that ends a session.

Other components are deliberately experiential rather than networked. Realistic G forces, combat deafness as a temporary loss of hearing, real night and thermal vision modes, adjustable sniper scopes, and backblast area and overpressure simulation all exist to make a moment feel physical rather than to change a state that must match across clients.

The catalog is wide enough that it is worth asking what the mod is not trying to be. It does not present itself as an AI overhaul, and the core feature list contains no entry for enemy behaviour. The components cover the player, the vehicle, the environment, and the logistics layer, with logistics and the map screen improvements, marker placement and map tools, sitting between them. A server that wants a full overhaul of enemy tactics is looking for a different project.

Getting started means Arma 3, CBA A3, and a wiki

The dependency is stated at the top of the project's documentation and repeated in the getting started section: ACE3 requires Arma 3 and the latest version of CBA A3. The CBA A3 requirement is not a suggestion. If you install ACE3 against an older CBA build, you get a partial system, and the project does not publish a compatibility matrix that would let you work out which combinations are safe. Plan to run the latest CBA A3 release.

The project gives no single command that installs the mod. Instead it points you to a hosted installation guide and an information center, and the sensible flow is to read the installation guide, obtain the CBA A3 release, then obtain the ACE3 build you intend to run, and only then decide which components you want to strip out. Since the removal happens at configuration time rather than at runtime, that order matters. You should know which components you are dropping before you build, not after players report a missing interaction.

For developers rather than end users, the project offers two build routes. One is to set up a development environment and build your own version, using the workspace manifest shown earlier and the build.bat script at the repository root. The other is to consume a prebuilt artifact.

Testing a branch through artifacts and a workshop subscription

Because the mod is assembled from many components, the risk of shipping a broken configuration is real, and the project has a specific answer to it. To test the latest development changes, you can download the artifact of the branch you want to test, or you can subscribe to Anrop ACE3 Master on the workshop to test the master branch. The artifact route comes from a GitHub Actions workflow named arma.yml, so the CI system produces a packaged build per branch and the tester consumes that rather than a local compile.

This matters for the adoption decision. If you run a public server, you can validate a specific commit's artifact before it becomes a release, which is a tighter loop than waiting for a tag. The recent release history shows a versioned cadence: v3.21.1 on 2026-08-11, v3.21.2 Release Candidate 1 on 2026-08-18, and v3.21.2 on the same day later. The release candidate is a distinct, tagged artifact, so a cautious operator can test the candidate and fall back to the previous stable version if the stripped-down configuration misbehaves.

The maintenance picture is healthy on the evidence available. The repository is not archived, and the last push was on 2026-10-15, which is more recent than the most recent tag, so commits are landing on master ahead of the next release. The project also states that contributions are welcome and that pull requests containing bug fixes, refactors and new features are reviewed by other collaborators, with the process documented in the pull request guidelines. Downside of the same openness: configuration changes can shift between releases, so pin your build.

Where the documentation stays quiet

Several things a new user will want are not written down in the repository's own overview, and you should know that before you plan around them.

First, no public API for plugins is documented. The project invites contributions of features and refactors and says that modules include various customization options, but the overview does not list the functions, events, or setting keys that an outside script would call. A mission designer who wants to script against ACE3 should read the component source rather than assume a stable public surface.

Second, the licensing picture is stated in two different ways and you need to look at the file itself. The project text names the GNU General Public License (GPLv2) and links it in the README, while the licence field on the GitHub page records a custom licence that GitHub cannot classify, pointing at the LICENSE file for the actual terms. Read that file before you redistribute a customized build, especially since the project's own condition is that changes you make are open to the public.

Third, the removal mechanism is described in prose but the exact file or setting that excludes a component is not named in the overview, so the build step for your own tailored version has to be worked out from the build configuration in the repository. The same applies to the medical level selection and the client and server settings, both of which are promised as configurable without a list of keys. Assume you will be reading component code on day one, not just reading the wiki.

Editorial conclusion

ACE3 fits teams that want simulation depth and accept CBA A3 as a hard dependency, and that are willing to read a wiki before touching the configuration. It does not fit a project that wants a single-file quick install, a mod with a stable API for third party plugins, or a plugin author targeting a documented public interface. Before adopting, confirm that the CBA A3 build you plan to run is the latest one, that the branch artifacts you test do not diverge from tagged releases, and that the components you strip out do not break the interaction and medical systems you still want.

Frequently asked questions

Official sources

1. acemod/ACE3 on GitHub
2. Issues
3. Project website
4. README
5. Releases