Skip repeated Three texture disposal scans

CHANGELOG.md

@@ -32,6 +32,7 @@
 - Performance: capture disassembly original transforms only for dragged parts and cache repeated Live Preview embed path resolution, reducing large-assembly interaction and workspace editor setup work.
 - Performance: update Three.js focus selection incrementally so switching selected parts in large assemblies no longer restores and re-dims every mesh.
 - Performance: prepare each unique Three.js material once during model load, avoiding repeated texture audit and anisotropy updates on shared-material large models.
+- Performance: skip repeated Three.js texture scans when disposing shared materials during model switches, reducing large-model close/reload stalls.
 - Performance: avoid forcing an unchanged plugin `data.json` rewrite during unload; only pending dirty state is flushed.
 - Performance: load inline preview modules in parallel and defer heading-pin DOM observers until the workspace layout is ready, reducing plugin startup work.
 - Performance: read absolute-path model files without an extra full-buffer copy when Node returns a whole file buffer, reducing memory spikes for large converted GLB assets.

src/render/three/scene.ts

@@ -1862,6 +1862,9 @@ export class ThreeModelPreview implements WorkbenchPreview {
     materialIds: Set<string>,
     textureIds: Set<string>,
   ): void {
+    if (materialIds.has(material.uuid)) {
+      return;
+    }
     const record = material as unknown as Record<string, unknown>;
     for (const value of Object.values(record)) {
       if (value instanceof Texture && !textureIds.has(value.uuid)) {
@@ -1877,10 +1880,8 @@ export class ThreeModelPreview implements WorkbenchPreview {
       }
     }
 
-    if (!materialIds.has(material.uuid)) {
-      material.dispose();
-      materialIds.add(material.uuid);
-    }
+    material.dispose();
+    materialIds.add(material.uuid);
   }
 
   private fitCameraToObject(root: Object3D, rootBounds?: PreviewBounds): void {