motion_graphics_basics v1.0.0

name: "motion_graphics_basics" description: "Create simple motion graphics with open-source tools: keyframed lower thirds, animated titles, and kinetic typography. Use when asked to animate text or shapes, build a lower third, add motion to a title card, or render kinetic typography without After Effects." metadata: { "includeInPrompt": true }

Motion Graphics Basics

Purpose

Produce simple, professional motion graphics using only open-source tools: keyframed animation of text and shapes, lower thirds, animated title cards, and kinetic typography. The primary engine is Blender driven headlessly through its Python API (bpy) — scriptable, reproducible, no GUI needed. Natron covers node-based compositing; OGRAF/HTML5 covers broadcast-graphics templates.

Workflow

1. Pick the tool for the job

• Blender (headless bpy) — default choice. Keyframed text/shapes, eased motion, transparent renders. Fully scriptable; bin/lower_third.py is the reference implementation. Use for: lower thirds, title cards, kinetic type sequences, animated shapes.
• Natron — node-graph compositing (Transform/Roto keyframing, Curve editor). Use for: compositing motion graphics over footage, when a node workflow fits better than a 3D scene. GUI-first; see references/tool-landscape.md.
• OGRAF / HTML5 templates — use for reusable broadcast graphics (lower thirds, scoreboards, tickers) that must deploy across renderers. EBU open standard; open-source authoring via Zero Density's OGraf Studio. See references/tool-landscape.md.

2. Write a timing plan before animating

Every graphic gets: in-animation → hold → out-animation, in frames. Defaults (30 fps): in 12–24 frames (0.4–0.8 s), hold as long as the beat needs, out 12–24 frames. See references/keyframes-and-easing.md for the timing-plan template and easing rules. Never skip this step — unplanned motion looks amateur.

3. Animate with keyframes + easing

• Keyframe position, scale, rotation, and opacity — never more properties than the design needs.
• Default interpolation: Bezier with EASE_IN_OUT (or EASE_OUT for entrances). Never ship linear interpolation on visible motion — it looks robotic. See references/keyframes-and-easing.md.
• Stagger related elements (bar → title → subtitle) by 4–8 frames so motion cascades instead of firing all at once.

4. Render transparent, composite with ffmpeg

• Render RGBA (transparent film) as a PNG sequence from Blender, then assemble with ffmpeg. Verified alpha-preserving master: ffmpeg -framerate 30 -i frame_%04d.png -c:v png -pix_fmt rgba lower_third.mov (QuickTime PNG codec keeps the alpha channel — confirmed via alphaextract.) For previews, composite over a background: overlay the PNG sequence on a color source and encode H.264/VP9. Note: VP9-in-WebM silently drops alpha on stock ffmpeg builds even with -pix_fmt yuva420p — never use .webm as the alpha master.
• Keep everything title-safe: content inside a ~5% inset from each edge.

5. Kinetic typography

Reveal text word-by-word or phrase-by-phrase synced to the voiceover beat; one idea per beat; hierarchy through size/weight/color, not decoration. Full rules in references/kinetic-typography-and-lower-thirds.md.

Output Contract

• A rendered file: an alpha-preserving master (.mov, PNG codec) and/or a flattened preview (.mp4, .webm), at a stated resolution/fps — or a reusable template/script.
• Every deliverable states: resolution, fps, duration, in/hold/out timing, and the tool used.
• Text legible at the target size (names ~48–60 px, supporting text ~28–36 px at 1080p), high contrast, no hairline strokes.

Operating Rules

1. Open-source tools only for the core build (Blender, Natron, ffmpeg, OGRAF tooling). Proprietary tools (After Effects, Remotion — which is not fully open source) may be named as alternatives, never as the build path.
2. No linear interpolation on visible motion — Bezier + easing, always.
3. Verify renders: open the output and check at least the first, middle, and last frames for legibility, safe margins, and correct timing. Fix and re-render rather than shipping a broken file.
4. Keep SKILL.md-level claims verifiable: tool capabilities and license terms come from primary sources (see scratch/motion-graphics-basics-sources.md in skill-production). Unverifiable = cut or frame as opinion.
5. bin/lower_third.py is the tested reference — extend it before writing a new Blender script from scratch.