Recast Nav Mesh in a level instance has been modified without changing anything

Development Programming & Scripting
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1

Hi Epic Staffs

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Our level designers complained that the RecastNavMesh actor was constantly being modified, prompting them to submit every time. This confused them.

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Through our testing, we were able to reproduce this behavior.

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A level structure similar to this is needed:

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  • Parent Level
    • Level Instance Actor
      • SubLevel
        • Recast Nav Mesh

Normally, after loading the Parent Level, a new Recast Nav Mesh Actor is generated within that Parent Level.

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However, once the level structure shown above is generated,

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it seems that every time the Parent Level is opened, the Recast Nav Mesh Actor is somehow set to Dirty, prompting a need to re-save.

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The problem disappeared after deleting the Level Instance Actor ‘SubLevel’.

What we want:

  • We don’t want to resave the Recast Nav Mesh Actor when we didn’t touching anything

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Steps to Reproduce

  • Open the test project
  • Open the ‘Parent Level’
  • Open the ‘Sublevel’ or any other level
  • You will see a dialog that told us we need to save the RecastNavMesh-Default actor since it has been modified

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3

The navmesh shows as dirtied due to loading in the NavMeshBoundsVolume in the level instance. It attempts to build a navmesh using that bounds volume which updates the tiles in the resulting RecastNavMesh actor. Some features of WP still have very minimal support in navigation, and I do not believe they will be addressed any time soon. They have just been low priority as other navigation work has been done.

-James

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