set_mpci_vector_parameter_value
Override a vector parameter on a Material Parameter Collection Instance (MPCI) at runtime, creating the instance and pushing the value to the renderer without modifying the asset.
Instructions
Override one vector parameter on the Material Parameter Collection Instance (MPCI: the transient per-world values) of a collection on a world, the editor world by default, creating the instance when needed, and push it to the renderer. Pass rgba or r/g/b/a: r/g/b/a override the matching rgba entries, and channels given by neither are 0 (alpha 1), not the current value. Runtime only: the asset is untouched (set_collection_param_default edits it), nothing saved, no undo. Errors when parameter_name is not a vector parameter of the collection; scalars: set_mpci_scalar_parameter_value.
Returns: { collection_path: string, parameter_name: string, value_rgba: [number], readback_rgba: [number], readback_ok: bool, world_name: string }
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| a | No | Optional alpha channel | |
| b | No | Optional blue channel | |
| g | No | Optional green channel | |
| r | No | Optional red channel, alternative to rgba | |
| rgba | No | Optional [r, g, b, a] color value | |
| world_label | No | Empty or "editor" for the editor world (the default); otherwise the UWorld name of a live world context, compared case-insensitively (first match) | |
| parameter_name | Yes | Name of the vector parameter to override | |
| collection_path | Yes | Full /Game path of the parent MPC |