From 815d39c4712ca7a9e67f93537696a00e5dc69387 Mon Sep 17 00:00:00 2001
From: Victor Giers <mail@victorgiers.com>
Date: Mon, 27 Apr 2026 16:08:03 +0200
Subject: [PATCH] Improve model instance synchronization by adding render
 groups for visible displayed models and applying shadow state.

---
 src/viewport-three/viewport-host.ts | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/viewport-three/viewport-host.ts b/src/viewport-three/viewport-host.ts
index ee6429a2..177c27fd 100644
--- a/src/viewport-three/viewport-host.ts
+++ b/src/viewport-three/viewport-host.ts
@@ -5983,18 +5983,42 @@ export class ViewportHost {
   private syncSimulationModelInstances(
     runtimeScene: RuntimeSceneDefinition
   ): boolean {
+    let addedRenderGroup = false;
+
     for (const modelInstance of runtimeScene.modelInstances) {
       const renderGroup = this.modelRenderObjects.get(
         modelInstance.instanceId
       );
 
       if (renderGroup === undefined) {
-        return false;
+        const displayedModelInstance = this.getDisplayedModelInstanceById(
+          modelInstance.instanceId
+        );
+
+        if (
+          displayedModelInstance !== null &&
+          displayedModelInstance.enabled &&
+          displayedModelInstance.visible
+        ) {
+          this.addModelInstanceRenderGroup(
+            displayedModelInstance,
+            isModelInstanceSelected(
+              this.currentSelection,
+              displayedModelInstance.id
+            )
+          );
+          addedRenderGroup = true;
+        }
+        continue;
       }
 
       renderGroup.visible = modelInstance.visible;
     }
 
+    if (addedRenderGroup) {
+      this.applyShadowState();
+    }
+
     return true;
   }