Analyse STL/3MF on upload: bounding box + volume, cached in stl_cache

- StlCache model: filename, cube_x/y/z (mm), volume_ccm
- Migration 0007: stl_cache table
- app/stl_analysis.py: trimesh-based analyse() + get_cache_map()
  - Runs immediately after upload in both /jobs and /brackets/{id}/jobs
  - Skips .gcode (no geometry), caches per filename, idempotent
- Library selector in both modals now shows dimensions and volume
- requirements: trimesh==4.5.3

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

alembic/versions/0007_stl_cache.py

@@ -0,0 +1,35 @@
+"""stl_cache table for bounding box and volume
+
+Revision ID: 0007
+Revises: 0006
+Create Date: 2026-06-18
+
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0007"
+down_revision: Union[str, None] = "0006"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "stl_cache",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("filename", sa.String(255), nullable=False),
+        sa.Column("cube_x", sa.Float(), nullable=True),
+        sa.Column("cube_y", sa.Float(), nullable=True),
+        sa.Column("cube_z", sa.Float(), nullable=True),
+        sa.Column("volume_ccm", sa.Float(), nullable=True),
+        sa.Column("created_at", sa.DateTime(), nullable=False, server_default=sa.text("CURRENT_TIMESTAMP")),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("filename"),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("stl_cache")

app/models/__init__.py

@@ -7,6 +7,7 @@ from app.models.print_job import PrintJob
 from app.models.printer import Printer
 from app.models.printer_log import PrinterLog
 from app.models.printer_type import PrinterType
+from app.models.stl_cache import StlCache
 from app.models.todo import Todo
 
-__all__ = ["Base", "Printer", "PrinterLog", "PrinterType", "Filament", "JobBracket", "JobLog", "PrintJob", "Todo", "PricingConfig"]
+__all__ = ["Base", "Printer", "PrinterLog", "PrinterType", "Filament", "JobBracket", "JobLog", "PrintJob", "StlCache", "Todo", "PricingConfig"]

app/models/stl_cache.py

@@ -0,0 +1,18 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, Float, String, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.models.base import Base
+
+
+class StlCache(Base):
+    __tablename__ = "stl_cache"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    filename: Mapped[str] = mapped_column(String(255), unique=True)
+    cube_x: Mapped[float | None] = mapped_column(Float)   # mm
+    cube_y: Mapped[float | None] = mapped_column(Float)   # mm
+    cube_z: Mapped[float | None] = mapped_column(Float)   # mm
+    volume_ccm: Mapped[float | None] = mapped_column(Float)  # cm³
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())

app/routers/ui.py

@@ -19,6 +19,7 @@ from app.models.printer_type import PrinterType
 from app.models.pricing import PricingConfig
 from app.models.todo import Todo
 from app.stl import get_stl_dir, list_stl_files
+from app.stl_analysis import analyse, get_cache_map
 
 router = APIRouter()
 templates = Jinja2Templates(directory="app/templates")
@@ -137,7 +138,8 @@ def jobs_page(request: Request, q: str = "", db: Session = Depends(get_db)):
         "printers": db.query(Printer).order_by(Printer.name).all(),
         "filaments": db.query(Filament).order_by(Filament.material, Filament.color).all(),
         "brackets": db.query(JobBracket).order_by(JobBracket.name).all(),
-        "stl_files": list_stl_files(),
+        "stl_files": (stl_files := list_stl_files()),
+        "stl_cache": get_cache_map(stl_files, db),
     })
 
 
@@ -156,6 +158,7 @@ async def create_job(
     if stl_file and stl_file.filename:
         filename = stl_file.filename
         (get_stl_dir() / filename).write_bytes(await stl_file.read())
+        analyse(filename, db)
     elif stl_select:
         filename = stl_select
 
@@ -210,7 +213,8 @@ def bracket_detail(bracket_id: int, request: Request, db: Session = Depends(get_
         "active": "brackets",
         "bracket": bracket,
         "filaments": db.query(Filament).order_by(Filament.material, Filament.color).all(),
-        "stl_files": list_stl_files(),
+        "stl_files": (stl_files := list_stl_files()),
+        "stl_cache": get_cache_map(stl_files, db),
     })
 
 
@@ -228,6 +232,7 @@ async def add_jobs_to_bracket(
     if stl_file and stl_file.filename:
         filename = stl_file.filename
         (get_stl_dir() / filename).write_bytes(await stl_file.read())
+        analyse(filename, db)
     elif stl_select:
         filename = stl_select
 

app/stl_analysis.py

@@ -0,0 +1,47 @@
+import logging
+from pathlib import Path
+
+from sqlalchemy.orm import Session
+
+from app.models.stl_cache import StlCache
+
+logger = logging.getLogger("pops")
+
+_ANALYSABLE = {".stl", ".3mf"}
+
+
+def analyse(filename: str, db: Session) -> StlCache | None:
+    """Return cached analysis for filename, computing it if missing."""
+    existing = db.query(StlCache).filter(StlCache.filename == filename).first()
+    if existing:
+        return existing
+
+    from app.stl import get_stl_dir
+    filepath = get_stl_dir() / filename
+    if Path(filename).suffix.lower() not in _ANALYSABLE or not filepath.exists():
+        return None
+
+    try:
+        import trimesh
+        mesh = trimesh.load(str(filepath), force="mesh")
+        extents = mesh.extents          # [size_x, size_y, size_z] in mm
+        volume_mm3 = abs(mesh.volume)   # mm³ (negative for inverted normals)
+        entry = StlCache(
+            filename=filename,
+            cube_x=round(float(extents[0]), 2),
+            cube_y=round(float(extents[1]), 2),
+            cube_z=round(float(extents[2]), 2),
+            volume_ccm=round(volume_mm3 / 1000, 3),
+        )
+        db.add(entry)
+        db.commit()
+        return entry
+    except Exception:
+        logger.exception("STL analysis failed for %s", filename)
+        return None
+
+
+def get_cache_map(filenames: list[str], db: Session) -> dict[str, StlCache]:
+    """Bulk-fetch cached entries for a list of filenames."""
+    rows = db.query(StlCache).filter(StlCache.filename.in_(filenames)).all()
+    return {r.filename: r for r in rows}

app/templates/bracket_detail.html

@@ -114,7 +114,10 @@
                 {% if stl_files %}
                 <select name="stl_select" class="form-select bg-dark border-secondary text-white">
                   <option value="">— select file —</option>
-                  {% for f in stl_files %}<option value="{{ f }}">{{ f }}</option>{% endfor %}
+                  {% for f in stl_files %}
+                  {% set c = stl_cache.get(f) %}
+                  <option value="{{ f }}">{{ f }}{% if c %} — {{ c.cube_x|round(1) }}×{{ c.cube_y|round(1) }}×{{ c.cube_z|round(1) }} mm · {{ c.volume_ccm }} cm³{% endif %}</option>
+                  {% endfor %}
                 </select>
                 {% else %}
                 <p class="text-secondary small mb-0">No files in library yet.</p>

app/templates/jobs.html

@@ -129,7 +129,8 @@
                 <select name="stl_select" class="form-select bg-dark border-secondary text-white">
                   <option value="">— select file —</option>
                   {% for f in stl_files %}
-                  <option value="{{ f }}">{{ f }}</option>
+                  {% set c = stl_cache.get(f) %}
+                  <option value="{{ f }}">{{ f }}{% if c %} — {{ c.cube_x|round(1) }}×{{ c.cube_y|round(1) }}×{{ c.cube_z|round(1) }} mm · {{ c.volume_ccm }} cm³{% endif %}</option>
                   {% endfor %}
                 </select>
                 {% else %}

requirements.txt

@@ -6,3 +6,4 @@ pymysql==1.1.1
 cryptography==44.0.3
 jinja2==3.1.4
 python-multipart==0.0.20
+trimesh==4.5.3