diff --git a/src/composables/useLoad3dViewer.test.ts b/src/composables/useLoad3dViewer.test.ts
index a692871a3f0..9b05e1b983c 100644
--- a/src/composables/useLoad3dViewer.test.ts
+++ b/src/composables/useLoad3dViewer.test.ts
@@ -404,6 +404,23 @@ describe('useLoad3dViewer', () => {
           .intensity
       ).toBe(1)
     })
+
+    it('should preserve unknown fields on Model Config when restoring', async () => {
+      const viewer = useLoad3dViewer(mockNode)
+      const containerRef = document.createElement('div')
+
+      await viewer.initializeViewer(containerRef, mockSourceLoad3d as Load3d)
+      ;(
+        mockNode.properties!['Model Config'] as Record<string, unknown>
+      ).futureField = 'preserve-me'
+
+      viewer.restoreInitialState()
+
+      expect(
+        (mockNode.properties!['Model Config'] as Record<string, unknown>)
+          .futureField
+      ).toBe('preserve-me')
+    })
   })
 
   describe('applyChanges', () => {
@@ -457,6 +474,23 @@ describe('useLoad3dViewer', () => {
 
       expect(result).toBe(false)
     })
+
+    it('should preserve unknown fields on Model Config when applying', async () => {
+      const viewer = useLoad3dViewer(mockNode)
+      const containerRef = document.createElement('div')
+
+      await viewer.initializeViewer(containerRef, mockSourceLoad3d as Load3d)
+      ;(
+        mockNode.properties!['Model Config'] as Record<string, unknown>
+      ).futureField = 'preserve-me'
+
+      await viewer.applyChanges()
+
+      expect(
+        (mockNode.properties!['Model Config'] as Record<string, unknown>)
+          .futureField
+      ).toBe('preserve-me')
+    })
   })
 
   describe('refreshViewport', () => {
diff --git a/src/composables/useLoad3dViewer.ts b/src/composables/useLoad3dViewer.ts
index 4de6ea8a547..b048c17bb48 100644
--- a/src/composables/useLoad3dViewer.ts
+++ b/src/composables/useLoad3dViewer.ts
@@ -619,7 +619,11 @@ export const useLoad3dViewer = (node?: LGraphNode) => {
         intensity: initialState.value.lightIntensity
       }
 
+      const existingModelConfig = nodeValue.properties['Model Config'] as
+        | ModelConfig
+        | undefined
       nodeValue.properties['Model Config'] = {
+        ...existingModelConfig,
         upDirection: initialState.value.upDirection,
         materialMode: initialState.value.materialMode,
         gizmo: {
@@ -671,10 +675,13 @@ export const useLoad3dViewer = (node?: LGraphNode) => {
       }
 
       const gizmoTransform = load3d.getGizmoTransform()
+      const existingModelConfig = nodeValue.properties['Model Config'] as
+        | ModelConfig
+        | undefined
       nodeValue.properties['Model Config'] = {
+        ...existingModelConfig,
         upDirection: upDirection.value,
         materialMode: materialMode.value,
-        showSkeleton: false,
         gizmo: {
           enabled: gizmoEnabled.value,
           mode: gizmoMode.value,