Inquiry Summary (XVerse 3DGS + UE5.4 + nDisplay)

[YooNaga]

Describe the bug
In UE5.4 using XVerse 3DGS with nDisplay, Gaussian Splatting objects (and Niagara effects) only appear in the first viewport(s) but disappear or are clipped in subsequent viewports. In the nDisplay Config Preview the entire scene is visible, but at runtime parts of the GS objects vanish. Expanding Fixed Bounds (±100000 or larger) does not fix the issue.

To Reproduce
Steps to reproduce the behavior:

Set up an nDisplay configuration with multiple viewports (Projection Policy = Mesh, using nDisplayScreen).

Place a Gaussian Splatting object (XV3dGS) or Niagara system in the scene.

Run the project with nDisplay.

Observe that in the first viewport the GS object is visible, but in other viewports it disappears/clips.

Expected behavior
Gaussian Splatting objects (and Niagara effects) should render consistently across all nDisplay viewports without disappearing, regardless of viewport frustum or projection policy.

Screenshots

[Screenshot 1: nDisplay runtime view where GS disappears]

[Screenshot 2: nDisplay Config Preview showing full GS scene]

Desktop (please complete the following information):

OS: Windows 10/11

Unreal Engine: 5.4

XVerse Plugin: XV3dGS (latest release at time of testing)

Smartphone (please complete the following information):
N/A

Additional context

Projection Policy = Mesh (using nDisplayScreen).

Fixed Bounds set very large, Use Fixed Bounds = ON → issue persists.

Region size matches actual resolution (1920x1080).

In UE5.4, "Visibility Sync" and "Inner Frustum Culling" options are not exposed in nDisplay Root/Viewport details.

Possibly related to viewport frustum culling or mesh projection boundary handling in nDisplay.

Unsure if World Origin Rebasing contributes (still under review).