diff --git a/neo/engine/opengl/gl_d3d12shim.cpp b/neo/engine/opengl/gl_d3d12shim.cpp
index 65166635..d9346fa0 100644
--- a/neo/engine/opengl/gl_d3d12shim.cpp
+++ b/neo/engine/opengl/gl_d3d12shim.cpp
@@ -4219,6 +4219,15 @@ float QD3D12_TessellationDisplacementFade(float4 clipPos)
     return QD3D12_DistanceFadeFromClip(clipPos, QD3D12_TESS_DISTANCE_NEAR, QD3D12_TESS_DISTANCE_FAR);
 }
 
+float QD3D12_TessellationPatchEdgeFade(float3 bary)
+{
+    // Keep original patch edges on the undisplaced mesh. Brush seams and room
+    // corners often meet only at those edges; moving both sides along different
+    // normals can open real gaps that show the background.
+    float edgeDistance = min(bary.x, min(bary.y, bary.z));
+    return smoothstep(0.0, 0.08, edgeDistance);
+}
+
 float QD3D12_ComputeNormalMapTessEdgeFactor(VSOut a, VSOut b)
 {
     if (gUseNormalMap <= 0.5)
@@ -4340,6 +4349,7 @@ VSOut DSMain(HSConstOut tessFactors, float3 bary : SV_DomainLocation, const Outp
     float height = QD3D12_GetFilteredTessHeight(i.uv0);
     float centeredHeight = QD3D12_CleanCenteredTessHeight(height);
     float displacementFade = QD3D12_TessellationDisplacementFade(i.currClip);
+    displacementFade *= QD3D12_TessellationPatchEdgeFade(bary);
     float reliefConfidence = QD3D12_GetPomConfidence(i.uv0);
     float displacement = centeredHeight * gTessellationDisplacement * displacementFade * reliefConfidence;
     float3 displacedObjPos = i.objPos + objNormal * displacement;