update 3d scene example

examples/3d_scene/main.py

@@ -1,18 +1,12 @@
 #!/usr/bin/env python3
-import os
+from fastapi.staticfiles import StaticFiles
 
-from nicegui import ui
+from nicegui import app, ui
 
-ui.add_static_files('/static', f'{os.path.dirname(os.path.realpath(__file__))}/static')
+app.mount('/stl', StaticFiles(directory='static'), name='stl')
 
 with ui.scene(width=1024, height=800) as scene:
     scene.spot_light(distance=100, intensity=0.1).move(-10, 0, 10)
-    scene.stl('static/pikachu.stl').scale(0.1)
-    scene.move_camera(
-        -5, -3, 3,  # position
-        0, 0, 3,  # look at
-        0, 0, 1,  # up
-        0  # animation duration
-    )
+    scene.stl('/stl/pikachu.stl').move(x=-0.5).scale(0.06)
 
 ui.run()