render-stl-png

Render an STL to a PNG from a nice, consistent 3D angle ("Blender-ish" default perspective) with a solid color.

This is a deterministic software renderer:

• No OpenGL
• No Blender dependency
• Uses a simple camera + z-buffer + Lambert shading

Inputs

• STL file path (ASCII or binary)
• Output PNG path

Parameters

• --size <px>: image width/height (square), default 1024
• --bg "#rrggbb": background color, default #0b0f14
• --color "#rrggbb": mesh base color, default #4cc9f0
• --azim-deg <deg>: camera azimuth around Z, default -35
• --elev-deg <deg>: camera elevation, default 25
• --fov-deg <deg>: perspective field of view, default 35
• --margin <0..0.4>: framing margin as fraction of view, default 0.08
• --light-dir "x,y,z": directional light vector, default -0.4,-0.3,1.0

Usage

One-shot

python3 scripts/render_stl_png.py \
  --stl /path/to/model.stl \
  --out /tmp/model.png \
  --color "#ffb703" \
  --bg "#0b0f14" \
  --size 1200

Wrapper (recommended)

The wrapper creates a cached venv (so pillow is available) and runs the renderer.

bash scripts/render_stl_png.sh /path/to/model.stl /tmp/model.png --color "#ffb703"

Notes

• This is meant for marketing/preview images, not photorealism.
• If you need studio lighting / materials, use Blender — but this gets you 80% quickly and reproducibly.