From df9c4e499f7db18fb03238e166690a9925209cec Mon Sep 17 00:00:00 2001
From: sudhir <sudhir9297@gmail.com>
Date: Mon, 20 Apr 2026 11:25:36 +0530
Subject: [PATCH] Restrict ground occluder to recessed slabs

---
 .../src/components/renderers/site/site-renderer.tsx   | 11 ++++++++++-
 .../viewer/src/components/viewer/ground-occluder.tsx  | 10 +++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/packages/viewer/src/components/renderers/site/site-renderer.tsx b/packages/viewer/src/components/renderers/site/site-renderer.tsx
index e52b6c4c..c16e056a 100644
--- a/packages/viewer/src/components/renderers/site/site-renderer.tsx
+++ b/packages/viewer/src/components/renderers/site/site-renderer.tsx
@@ -55,7 +55,16 @@ export const SiteRenderer = ({ node }: { node: SiteNode }) => {
     })
 
     const next = nodeList
-      .filter((n): n is SlabNode => n.type === 'slab' && n.visible && n.polygon.length >= 3)
+      .filter(
+        (n): n is SlabNode =>
+          n.type === 'slab' &&
+          n.visible &&
+          n.polygon.length >= 3 &&
+          // Only recessed slabs should punch through the site ground.
+          // Positive slabs are real floor geometry and should not create a
+          // ghost footprint in the background ground fill.
+          (n.elevation ?? 0.05) < 0,
+      )
       .filter((n) => {
         if (!Number.isFinite(lowestLevelIndex)) return true
         const parentLevel = n.parentId ? levelIndexById.get(n.parentId as string) : undefined
diff --git a/packages/viewer/src/components/viewer/ground-occluder.tsx b/packages/viewer/src/components/viewer/ground-occluder.tsx
index c04e9d81..54be8b51 100644
--- a/packages/viewer/src/components/viewer/ground-occluder.tsx
+++ b/packages/viewer/src/components/viewer/ground-occluder.tsx
@@ -38,7 +38,15 @@ export const GroundOccluder = () => {
     const polygons: [number, number][][] = []
 
     Object.values(nodes).forEach((node) => {
-      if (!(node.type === 'slab' && node.visible && node.polygon.length >= 3)) {
+      if (
+        !(
+          node.type === 'slab' &&
+          node.visible &&
+          node.polygon.length >= 3 &&
+          // Only recessed slabs should punch through the ground plane.
+          (node.elevation ?? 0.05) < 0
+        )
+      ) {
         return
       }