OPAL can install O3DE either as a prebuilt binary or as a source build. Prebuilt engines are faster to get running; source builds let you patch the engine yourself. OPAL tracks which is which and only offers build actions where they make sense.
Installing a source build
On the Engine Downloads page, choose the Source platform filter (or a pre-release branch).
A source engine is usable without building it, which causes the entire source code to build alongside your project. A necessary process for source code editing/development work, but will cause longer-than-normal build times for your project.
To build it once, and be able to use it regularly thereafter, you can proceed to building your engine directly.
Building and rebuilding
Source engines expose a Build action on the Engines page. Prebuilt engines don’t — the action is disabled with a “Cannot build pre-built engine” note, since there’s nothing to compile.
OPAL runs the engine build through the Builds queue, so it’s pausable, resumable, and crash-safe like any other build.
An unbuilt source engine is clearly marked so you know it still needs a build before projects can use it prebuilt.
Script-Only mode
If you’re not compiling C++, turn on Script-Only mode (in the onboarding wizard or Settings). While it’s on, OPAL:
- Hides the Source option in Engine Downloads.
- Hides build actions on source engines.
- Notes that unbuilt source engines are unavailable in Script-Only mode.
This keeps the app focused on prebuilt, script-based work.