function initialize(runtimeArticulation) {
  const articulation = runtimeArticulation.articulation;

  const stages = articulation.stages;
  const length = stages.length;

  const runtimeStages = runtimeArticulation._runtimeStages;
  const runtimeStagesByName = runtimeArticulation._runtimeStagesByName;
  for (let i = 0; i < length; i++) {
    const stage = stages[i];
    const runtimeStage = new ModelArticulationStage({
      stage: stage,
      runtimeArticulation: runtimeArticulation,
    });

    // Store the stages in an array to preserve the order in which
    // they appeared in the 3D model.
    runtimeStages.push(runtimeStage);

    // Store the stages in a dictionary for retrieval by name.
    const stageName = stage.name;
    runtimeStagesByName[stageName] = runtimeStage;
  }
}
The runtime nodes that are affected by this articulation.

@memberof ModelArticulation.prototype
@type {ModelRuntimeNode[]}
@readonly

@private