The Hierarchy Merge operation merges groups of actors in the scene into single actors based on their software origin (e.g., 3ds Max, Revit, Rhino). It identifies hierarchical groups of objects, detects and removes duplicates, and merges the remaining groups into a unified actor. This operation helps optimize the scene by reducing the number of individual actors, improving rendering performance, and simplifying the actor hierarchy.

This operation is particularly useful for imported CAD or architectural models that come with complex hierarchies and many redundant groups.

CAD Example:

Parent actor in hierarchy has isGroupHead : true

Child actors in hierarchy have isGroupMember : true

Dependencies

Run Hierarchy Merge before Create Instances and Smart Merge for optimal results.

Best Practices

• Non-CAD Scenes: Even in non-CAD scenes, use this operation to consolidate the lowest-level actors and reduce their count.
• CAD Scenes: Best for Datasmith-imported scenes.
  • Rhino: Merges blocks into single actors.
  • 3ds Max: Consolidates groups.
  • Revit: Merges family instances.
• Review: Always review the scene post-merge to ensure no essential data is lost.

Considerations

• Destructive Process: The original actors are removed after merging. Back up your scene or use version control before running this operation.
• Data Loss Risk: Ensure hierarchical data is not needed before merging, as the operation may impact gameplay or other systems.
• Performance Impact: Large scenes may experience increased CPU and memory usage during the merge. Consider breaking the operation into smaller sections if necessary.