Engines
The Engines page is OPAL’s answer to the question “which O3DE do I use?”. Install as many versions as you want. Pin projects to specific versions. Remove engines you no longer need — with full awareness of what will break.
Install an engine
Click Install Engine (top right of the Engines page). OPAL offers three install modes:
- Latest stable — the most recent tagged release.
- Specific version — pick any prior tagged release.
- Source build — clone a branch and build locally. Useful when you need engine patches.
Installer downloads run in the Downloads queue. Source builds run in the Builds queue. Both are interrupt-safe — you can close OPAL mid-install and resume later.
Set a default engine
Your default engine is the one used for new projects when you don’t override it. Click the Set Default button on any installed engine. The badge updates immediately.
Switch a project to a different engine
Open the project’s Settings dialog (right-click the project card → Settings, or the gear icon). Change Engine to any installed engine. OPAL writes the pin into project.json and prompts for a rebuild.
Remove an engine
Click the Remove button on an installed engine. OPAL shows an impact preview:
- How many projects are pinned to this engine
- Which projects will be orphaned (no compatible fallback)
- Total disk space reclaimed
Confirm to remove. Orphaned projects remain in your list but will show a Missing engine warning until you assign a new engine or reinstall the old one.