[ModKit] Replaced custom mesh retains incorrect Area Box/source spatial data and editor values become inconsistent

[RainyIce1812]

• Game Version: v0.10.1 / Build 20260904.15051.W

• Platform: Steam Windows

• Mods: active
  If you have used mods before, please list them:
  OpenAssetLibrary — my own local test mod created with the official inZOI ModKit.

• Hardware Specifications & Operating System (OS version, CPU, GPU, RAM, storage…):
  Windows 11 Home 25H2, Build 26200.9168
  Intel Core Ultra 7 155H
  Intel integrated graphics
  32 GB LPDDR5 RAM
  SSD

  ModKit Version: 20260901.14952.W.MODKIT.EGS
  Unreal Engine Version shown by ModKit: 5.6.1
  Graphics RHI: D3D12 (SM6)

• Steps to Reproduce:

  1. Open the current official inZOI ModKit.
  2. Create or open a Build mod project.
  3. Duplicate BUILD/Stone01.
  4. Replace its original mesh with a custom Static Mesh.
  5. In my test, the replacement mesh is a simple rectangular stone block measuring exactly 100 × 50 × 50 cm.
  6. Assign the replacement Static Mesh to the duplicated object.
  7. Open Appearance → Bounds.
  8. Enable Show Bounds Box.
  9. Observe that the displayed Area Box does not correctly match the replacement mesh.
  10. Test Use Mesh Bounds For Area Box both enabled and disabled.
  11. Test Use Mesh Collision Box both enabled and disabled.
  12. Test manually setting Area Box Size to 2 × 1 × 1.
  13. Open the Data Editor.
  14. Open:
      ObjectBP → componentDatas → ObjectAreaBoxComponent → propertyMetaData
  15. Observe that the duplicated object still contains:
      areaBoxSize = (X=5,Y=4,Z=3)
  16. Change this directly to:
      areaBoxSize = (X=2,Y=1,Z=1)
  17. Also test changing the underlying:
      bUseMeshBoundsForAreaBox
      and
      bUseMeshCollisionBox
      values directly in the Data Editor.
  18. Save and validate the ObjectBP data.
  19. Return to the regular object editor.
  20. Display the Area Box again.

• Please provide the entire save file(s) from the date when the issue occurred.
  The main issue is reproducible directly inside the ModKit before a game save is involved.

  I also tested the packaged object in-game. I can provide the in-game test save and/or packaged local test mod if required.

• Details:

  I am trying to create modular Build Mode assets with the official inZOI ModKit.

  I duplicated BUILD/Stone01 and replaced its original mesh with my own custom Static Mesh.

  The replacement mesh is a simple stone block with exact dimensions of:

  100 × 50 × 50 cm

  The replacement mesh itself imports and works correctly.

  However, the Footprint / Area Box does not correctly update to match the replacement mesh.

  The displayed Area Box remains much larger and/or offset compared with the replacement mesh and appears to retain spatial information from the original duplicated Stone01 object.

  I tried multiple approaches to rule out a configuration mistake:

  • Use Mesh Bounds For Area Box enabled
  • Use Mesh Bounds For Area Box disabled
  • Use Mesh Collision Box enabled
  • Use Mesh Collision Box disabled
  • manually setting Area Box Size to 2 × 1 × 1
  • changing the ObjectAreaBoxComponent relative location
  • moving the custom mesh origin/pivot to bottom-center in Blender and reimporting the FBX
  • excluding the inherited Shadow component using Ignore Component Names
  • editing the ObjectBP data directly

  None of these approaches caused the displayed Area Box to correctly match the replacement 100 × 50 × 50 cm mesh.

  ModKit UI / Data Editor inconsistency

  I also observed an apparent inconsistency between the regular Build Mod editor UI and the underlying ObjectBP data.

  For example, in:

  Appearance → Bounds

  I explicitly configured:

  • Use Mesh Bounds For Area Box = disabled
  • Use Mesh Collision Box = disabled
  • Area Box Size = 2 × 1 × 1

  However, when I opened the corresponding object in the Data Editor, the underlying:

  ObjectBP → componentDatas → ObjectAreaBoxComponent → propertyMetaData

  still contained:

  bUseMeshBoundsForAreaBox = True

  bUseMeshCollisionBox = True

  areaBoxSize = (X=5,Y=4,Z=3)

  These values did not correspond to what I had configured in the normal ModKit Bounds UI.

  I then changed the values directly in the Data Editor as well.

  For example, I changed:

  areaBoxSize = (X=5,Y=4,Z=3)

  directly to:

  areaBoxSize = (X=2,Y=1,Z=1)

  and also tested changing the mesh-bounds and collision-box flags directly in the ObjectBP data.

  Even after directly editing the ObjectBP values, saving the changes and validating the data, the Area Box displayed by the normal object editor still did not correctly correspond to the replacement mesh.

  This makes it difficult to determine which representation is authoritative and suggests that the regular editor UI, ObjectBP component data, and generated/displayed Area Box may not remain synchronized after replacing the mesh of a duplicated object.

  In-game behaviour

  The replacement mesh itself is usable in-game.

  Smart Object Snapping with X can snap copies of the custom block side-by-side correctly.

  Holding Alt also allows the blocks to be freely positioned and moved into each other.

  So the replacement Static Mesh itself is clearly placeable.

  However, the footprint/bounds data in the ModKit still does not correctly correspond to the replacement mesh.

  There is also another indication that spatial data from the original duplicated object is retained.

  Because the object was duplicated from Stone01, it still inherited the original interaction slots and behaviours.

  For example, the original “vent frustration” / kicking interaction is still available.

  When the Zoi performs this interaction, the Zoi kicks at the old interaction position rather than at the actual position of the replacement mesh.

  Other inherited Stone01 behaviour is also still present, including observing the stone.

  This suggests that replacing the mesh of a duplicated object does not reliably regenerate or update all spatial data associated with the new mesh.

  The issue appears to affect at least:

  • Footprint / Area Box data
  • synchronization between the normal Bounds editor and ObjectBP data
  • inherited interaction slot locations
  • interactions tied to the original object’s geometry

  This makes it difficult to create reliable modular custom Build Mode assets.

  Expected Result

  After replacing the mesh of a duplicated Build object, the ModKit should allow the object’s footprint/bounds and interaction locations to correctly correspond to the replacement mesh.

  When Use Mesh Bounds For Area Box is enabled, the Area Box should reflect the actual bounds of the replacement mesh.

  When a manual Area Box Size is configured, the explicitly configured Area Box should be used and displayed correctly.

  Values configured in the normal ModKit Bounds UI and values stored in the corresponding ObjectBP data should remain synchronized.

  Inherited interaction positions should either update appropriately for the replacement object or be removable/reconfigurable.

  Actual Result

  The Area Box remains incorrect and appears to retain or derive spatial information from the original duplicated object.

  The values shown/configured in the regular Bounds UI and the values found in the underlying ObjectBP data can also disagree.

  Directly editing the ObjectBP data does not result in the Area Box correctly matching the replacement mesh.

  Inherited interaction positions also remain at locations corresponding to the original object instead of the replacement geometry.

  Additional screenshot

  

In summary, I tried every available method I could find to correct the bounds, including the regular Bounds UI, manual Area Box sizing, ObjectAreaBoxComponent transforms, mesh origin/pivot changes, excluding inherited components, and direct ObjectBP edits.

The Area Box can be changed, but I could not make it reliably match the actual replacement mesh.

Changing the component transform or other related values may move or alter the box, but it does not result in a correct and stable footprint for the custom mesh.

At this point, it appears impossible to configure accurate bounds for this replaced custom object using the currently available ModKit controls.