text-version-stamp

Text Version Stamp

A runnable example that builds a beveled 3D stamp of the running Blender version — a TextCurve (bpy.data.curves.new(type='FONT')) whose body is the live bpy.app.version_string, so every render self-documents which Blender produced it. CI artifacts made this way are self-labeling.

What it witnesses: the TextCurve data-API contract. curves.new(type='FONT') returns a Curve subclass, the built-in font ("Bfont Regular") is always loaded even headless, body is plain assignable text that regenerates geometry on edit (more characters → strictly wider evaluated mesh), and extrude / bevel_depth produce exactly predictable solids: the evaluated mesh z-extent equals 2 × (extrude + bevel_depth) and the round bevel widens the outline in-plane by 2 × bevel_depth. Flat text (no extrude, no bevel) is already filled — faces exist — but strictly planar. The check also witnesses the depsgraph lifetime hazard: after to_mesh_clear() the returned Mesh reference is dead and any access raises ReferenceError.

Version divergence: the string format itself differs — "5.1.2" on 5.x but "4.5.11 LTS" on 4.5 (the suffix is part of version_string). The check therefore asserts the contract that holds on both: version_string starts with the dotted bpy.app.version tuple. Code that parses version_string as a bare semver breaks on every LTS build; branch on the bpy.app.version tuple instead.

Run

# Cheap correctness check (no render) — the CI check:
blender --background --python text_version_stamp.py --

# Also render a still (EEVEE on a GPU host; use --engine cycles on GPU-less hosts):
blender --background --python text_version_stamp.py -- --output stamp.png
blender --background --python text_version_stamp.py -- --output stamp.png --engine cycles

It exits non-zero on failure (wrong subclass, missing font, body/version mismatch, non-planar flat text, extrude/bevel closed form off, geometry not regenerating, or a to_mesh_clear() reference surviving). The blender-smoke workflow runs the check on Blender 4.5 LTS and 5.1. The render scales the stamp to a constant width, so the frame holds for any version-string length.

The --output render path additionally measures framing against the Layer 1 band via examples/gallery_framing.py (exit 10 on violation) before writing the still.