Simplify STL viewer layout

README.md

@@ -1,6 +1,6 @@
 # STL to TIFF Gradio App
 
-This project provides a Gradio app that takes an uploaded STL file, slices it along the Z axis, saves each slice as a TIFF image, and lets you browse the stack inside the UI.
+This project provides a Gradio app that takes an uploaded STL file, shows an interactive 3D viewer, slices it along the Z axis, saves each slice as a TIFF image, and lets you browse the stack inside the UI.
 
 ## Run
 
@@ -14,6 +14,7 @@ Then open the local Gradio URL in your browser, upload an STL file, and generate
 ## What the app does
 
 - Uploads a single `.stl` file
+- Shows an interactive 3D viewer for rotating the model
 - Lets you choose layer height and XY pixel size
 - Produces one `.tif` image per slice
 - Lets you step through the slice stack in the browser

app.py

@@ -6,7 +6,7 @@ from typing import Any
 import gradio as gr
 from PIL import Image
 
-from stl_slicer import SliceStack, slice_stl_to_tiffs
+from stl_slicer import SliceStack, load_mesh, slice_stl_to_tiffs
 
 
 ViewerState = dict[str, Any]
@@ -21,6 +21,10 @@ def _empty_state() -> ViewerState:
     return {"tiff_paths": [], "z_values": []}
 
 
+def _reset_slider() -> dict[str, Any]:
+    return gr.update(minimum=0, maximum=0, value=0, step=1, interactive=False)
+
+
 def _stack_to_state(stack: SliceStack) -> ViewerState:
     return {
         "tiff_paths": [str(path) for path in stack.tiff_paths],
@@ -43,6 +47,30 @@ def _format_summary(stack: SliceStack, source_name: str) -> str:
     )
 
 
+def _format_model_status(source_name: str) -> str:
+    return "\n".join(
+        [
+            "### Model Loaded",
+            f"- Source: `{source_name}`",
+            "- Rotate the model in the 3D viewer, then choose slice settings and generate the TIFF stack.",
+        ]
+    )
+
+
+def _format_model_details(source_name: str, mesh) -> str:
+    extents = mesh.extents
+    return "\n".join(
+        [
+            "### Model Details",
+            f"- Source: `{source_name}`",
+            f"- Extents: `{extents[0]:.3f} x {extents[1]:.3f} x {extents[2]:.3f}`",
+            f"- Faces: `{len(mesh.faces)}`",
+            f"- Vertices: `{len(mesh.vertices)}`",
+            f"- Watertight: `{'yes' if mesh.is_watertight else 'no'}`",
+        ]
+    )
+
+
 def _slice_label(state: ViewerState, index: int) -> str:
     path = Path(state["tiff_paths"][index]).name
     z_value = state["z_values"][index]
@@ -64,6 +92,36 @@ def _render_selected_slice(state: ViewerState, index: int) -> tuple[str, Image.I
     )
 
 
+def load_model_assets(stl_file: str | None):
+    if not stl_file:
+        return (
+            "Upload an STL file to begin.",
+            _empty_state(),
+            _reset_slider(),
+            "No slice stack loaded yet.",
+            None,
+            None,
+            None,
+            None,
+            "No model loaded yet.",
+        )
+
+    mesh = load_mesh(stl_file)
+    source_name = Path(stl_file).name
+
+    return (
+        _format_model_status(source_name),
+        _empty_state(),
+        _reset_slider(),
+        "No slice stack loaded yet.",
+        None,
+        None,
+        None,
+        stl_file,
+        _format_model_details(source_name, mesh),
+    )
+
+
 def generate_stack(
     stl_file: str | None,
     layer_height: float,
@@ -123,8 +181,8 @@ def build_demo() -> gr.Blocks:
         gr.Markdown(
             """
             # STL to TIFF Slicer
-            Upload an STL, choose a layer height and XY pixel size, and generate a TIFF stack.
-            Use the slider or the previous and next buttons to browse through the resulting slices.
+            Upload an STL to inspect it in a rotatable 3D viewer.
+            Then choose a layer height and XY pixel size, generate the TIFF stack, and browse the slices below.
             """
         )
 
@@ -155,12 +213,19 @@ def build_demo() -> gr.Blocks:
 
             with gr.Column(scale=2):
                 summary = gr.Markdown("Upload an STL file to begin.")
+                model_details = gr.Markdown("No model loaded yet.")
+                model_viewer = gr.Model3D(
+                    label="Interactive 3D Viewer",
+                    display_mode="solid",
+                    clear_color=(0.94, 0.95, 0.97, 1.0),
+                    height=360,
+                )
                 slice_label = gr.Markdown("No slice stack loaded yet.")
                 slice_preview = gr.Image(
                     label="Slice Preview",
                     type="pil",
                     image_mode="L",
-                    height=520,
+                    height=420,
                 )
                 with gr.Row():
                     prev_button = gr.Button("Previous Slice")
@@ -174,6 +239,22 @@ def build_demo() -> gr.Blocks:
                     interactive=False,
                 )
 
+        stl_file.change(
+            fn=load_model_assets,
+            inputs=stl_file,
+            outputs=[
+                summary,
+                state,
+                slice_slider,
+                slice_label,
+                slice_preview,
+                download_zip,
+                current_tiff,
+                model_viewer,
+                model_details,
+            ],
+        )
+
         generate_button.click(
             fn=generate_stack,
             inputs=[stl_file, layer_height, pixel_size],