Python and Blueprint

UDreamFXEditorLibrary exposes every editor command to Python and Blueprint, forwarding to the same bodies the menus call.

import unreal

lib = unreal.DreamFXEditorLibrary

lib.rebuild_all_sources()                   # = Tools ▸ DreamFX ▸ Rebuild DFX
lib.verify_all_sources()                    # = Verify DFX
print(lib.write_workspace_file())           # writes the workspace, does not launch it

lib.export_system(unreal.load_asset("/Game/FX/NS_Spark"))
lib.adopt_system(unreal.load_asset("/Game/FX/NS_Spark"), True)   # True = skip the confirmation

bSkipConfirmation suppresses the dialog only

It removes the modal confirmation and nothing else. Both refusals still apply — DFX8010 (something is unrepresentable) and DFX8011 (another source already declares this asset) — reported as a toast and a log line instead of a dialog.

The reason is direct: a modal with no one to click it would block the calling thread.

What it is good for

Bulk migration. Sweep a set of assets, adopt the ones that decompile cleanly, and list the rest for a human:

import unreal

lib = unreal.DreamFXEditorLibrary
registry = unreal.AssetRegistryHelpers.get_asset_registry()

for data in registry.get_assets_by_path("/Game/VFX", recursive=True):
    asset = data.get_asset()
    if isinstance(asset, unreal.NiagaraSystem):
        lib.export_system(asset)          # export everything; the originals are never touched

A gate inside another toolchain. Feed the result of verify_all_sources() into your own release check.

A scheduled rebuild in-editor. Run rebuild_all_sources() once after a branch switch rather than letting the watcher meet a hundred changes at once (see the bulk gate in the daily loop).

The command line is the headless path

The Python surface runs inside the editor process. For headless work use dfx.ps1 — it runs the commandlet, with the same pipeline and the same diagnostic codes, and needs no UI at all.