diff --git a/packages/viewer/src/components/renderers/node-renderer.tsx b/packages/viewer/src/components/renderers/node-renderer.tsx
index f2045fb4..7140c9bc 100644
--- a/packages/viewer/src/components/renderers/node-renderer.tsx
+++ b/packages/viewer/src/components/renderers/node-renderer.tsx
@@ -1,6 +1,7 @@
 'use client'
 
-import { useScene, type AnyNode } from '@pascal-app/core'
+import { type AnyNode, nodeRegistry, type RendererSource, useScene } from '@pascal-app/core'
+import { type ComponentType, lazy, Suspense } from 'react'
 import { BuildingRenderer } from './building/building-renderer'
 import { CeilingRenderer } from './ceiling/ceiling-renderer'
 import { ColumnRenderer } from './column/column-renderer'
@@ -10,23 +11,60 @@ import { FenceRenderer } from './fence/fence-renderer'
 import { GuideRenderer } from './guide/guide-renderer'
 import { ItemRenderer } from './item/item-renderer'
 import { LevelRenderer } from './level/level-renderer'
-import { RoofSegmentRenderer } from './roof-segment/roof-segment-renderer'
 import { RoofRenderer } from './roof/roof-renderer'
+import { RoofSegmentRenderer } from './roof-segment/roof-segment-renderer'
 import { ScanRenderer } from './scan/scan-renderer'
 import { SiteRenderer } from './site/site-renderer'
 import { SlabRenderer } from './slab/slab-renderer'
 import { SpawnRenderer } from './spawn/spawn-renderer'
-import { StairSegmentRenderer } from './stair-segment/stair-segment-renderer'
 import { StairRenderer } from './stair/stair-renderer'
+import { StairSegmentRenderer } from './stair-segment/stair-segment-renderer'
 import { WallRenderer } from './wall/wall-renderer'
 import { WindowRenderer } from './window/window-renderer'
 import { ZoneRenderer } from './zone/zone-renderer'
 
+// Cache lazy components by their RendererSource so React.lazy isn't re-invoked
+// on every render — that would create a new Suspense boundary each time.
+const lazyCache = new WeakMap<RendererSource<AnyNode>, ComponentType<{ node: AnyNode }>>()
+
+function getRegistryRenderer(
+  source: RendererSource<AnyNode>,
+): ComponentType<{ node: AnyNode }> | null {
+  const cached = lazyCache.get(source)
+  if (cached) return cached
+  // GLB / instanced-GLB sources lower onto built-in renderers landed in
+  // Phase 5 — for now only parametric (lazy module) sources are honored.
+  if (source.kind !== 'parametric') return null
+  const Comp = lazy(source.module) as unknown as ComponentType<{ node: AnyNode }>
+  lazyCache.set(source, Comp)
+  return Comp
+}
+
+function RegistryRenderer({ node }: { node: AnyNode }) {
+  const def = nodeRegistry.get(node.type)
+  if (!def) return null
+  const Renderer = getRegistryRenderer(def.renderer as RendererSource<AnyNode>)
+  if (!Renderer) return null
+  return (
+    <Suspense fallback={null}>
+      <Renderer node={node} />
+    </Suspense>
+  )
+}
+
 export const NodeRenderer = ({ nodeId }: { nodeId: AnyNode['id'] }) => {
   const node = useScene((state) => state.nodes[nodeId])
 
   if (!node) return null
 
+  // Registry-first: if a NodeDefinition is registered for this kind (via
+  // @pascal-app/nodes or a future plugin), it owns the render. Falls through
+  // to the legacy chain below for kinds not yet migrated. Legacy chain is
+  // removed in Phase 6 once every kind is registry-backed.
+  if (nodeRegistry.has(node.type)) {
+    return <RegistryRenderer node={node} />
+  }
+
   return (
     <>
       {node.type === 'site' && <SiteRenderer node={node} />}