PME Treasure

Enable a PME action only when an option is turned on

3 min read

Outcome

Keep an action visible in a Custom layout, but disable it until a PME Boolean Property named EnableAdvanced is on:

row = L.row(); row.enabled = bool(props("EnableAdvanced")); operator(row, "pme.invoke_macro", text="Run Advanced", pm_name="Advanced Macro")

The disabled button tells users that the action exists and shows which option controls its availability.

Steps

  1. Create a Boolean Property in PME’s Property Editor. Give it a stable identifier such as EnableAdvanced.
  2. Place that Property control in the same Popup Dialog or a nearby settings panel.
  3. Add a Custom item for the dependent action.
  4. Create a row, set row.enabled from props("EnableAdvanced"), then draw the action into that row.
  5. Test the layout with the option off and on. The action should remain visible in both states and become clickable only when enabled.

The example draws PME’s named Macro invoker into the row. Another public Blender operator can use the same enabled-row pattern; only the row’s availability depends on the Property. Avoid building new examples around PME’s internal legacy pme.exec convenience operator.

Why disable instead of hide

A hidden control makes a compact interface, but it can also make the feature undiscoverable. A disabled control is usually better when:

  • the prerequisite is visible nearby;
  • users should understand what becomes available;
  • the temporary unavailable state is normal, not an error.

Use Poll-gated or conditional drawing when the control is meaningless in the current Blender context—for example, a mesh-only action while no mesh exists. Use row.enabled when the action is meaningful but awaits a user-controlled option.

Pitfalls

  • Use the registered Property identifier. An unknown name reads as None, so bool(...) disables the row instead of creating scratch state.
  • Draw the operator and set its properties in the Custom item so the action runs on click rather than while the UI is drawn.
  • Treat the disabled state as a UI hint; reusable external scripts should also validate their prerequisites.
  • Keep the enabling option close enough that users can discover how to unlock the action.
  • When Blender already owns the relevant state, read that property directly so the button stays in sync.

The source post used pme.exec. The example above keeps its enabled-row design while using PME 2.1’s dedicated pme.invoke_macro entry point.

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