add more doc

app.py

@@ -202,6 +202,7 @@ _DESCRIPTION = '''
 </div>
 
 * Input can be only text, only image, or both image and text. 
+* Output is a `ply` file containing the 3D Gaussians, please check our [repo](https://github.com/3DTopia/LGM/blob/main/readme.md) for visualization and mesh conversion.
 * If you find the output unsatisfying, try using different seeds!
 '''
 
@@ -235,7 +236,7 @@ with block:
                 # final video results
                 output_video = gr.Video(label="video")
                 # ply file
-                output_file = gr.File(label="ply")
+                output_file = gr.File(label="3D Gaussians (ply format)")
             with gr.Tab("Multi-view Image"):
                 # multi-view results
                 output_image = gr.Image(interactive=False, show_label=False)