resolution-aspect-decision

Purpose

Avoid the most common render planning mistake: rendering at one aspect / resolution and cropping or upscaling to fit. Pick the consumer's required output upfront.

Quick start

• Identify the consumer use case and target placement (web hero, social feed, print, app asset).
• Pick the delivery aspect ratio (W:H) upfront so camera framing matches target placement.
• Pick exact render resolution (W × H in pixels) and DPI / PPI for print deliverables.
• Define per-stream resolution records if multiple delivery targets exist.
• Pin the record for the operator to enter in Blender scene render properties (no rendering, no post-render resizing).

When to use

• before render
• when consumer requires specific aspect / resolution
• before composition planning (aspect drives composition rules)

When not to use

• after render is complete (no benefit) → use ../camera-composition/SKILL.md (no benefit)
• pure modeling → use ../output-format-decision/SKILL.md (Delegates out-of-scope requests to output-format-decision)
• internal preview-only renders (any reasonable size works) → use ../composition-quality-checker/SKILL.md (any reasonable size works)

Trigger phrases

• "what resolution"
• "how big should the render be"
• "16:9 or square"

Prerequisites / readiness

• Consumer use case and target placement are known (or ready to be confirmed with one question).
• Color config (color-management-decision), container/codec (output-format-decision), and engine (cycles-vs-eevee-decision) remain separate decisions owned by their respective skills.

Input schema

Required inputs

Optional inputs

Assumptions to confirm

• The target machine and render budget can handle the pinned W × H resolution.
• Multiple aspect ratios will be framed via camera/scene setup rather than post-render cropping.

Output schema

Primary output

A 3-line resolution record per target stream:

1. Aspect ratio (W:H)
2. Render resolution (W × H pixels)
3. DPI / PPI (explicit value for print; N/A (screen delivery) for digital)

Secondary output

• Per-stream resolution rules when delivering to multiple placements
• Caveats (hardware memory/time budget notes, framing handoff requirements)

Evidence / caveat output

Runtime status: Not Run
Artifact status: Not Produced
Evidence used: <consumer spec, or "none">
Limitations: <unconfirmed platform specs, memory/time budget caveats>

Truth-state rule: Pinning an aspect ratio and resolution is a planning decision and never produces a file. Default to Runtime status: Not Run and Artifact status: Not Produced. Truth states are downgrade-only and must never be upgraded by this skill.

Required laws

• ../../laws/evidence-before-done.md
• ../../laws/non-blender-user-language.md
• ../../laws/no-arbitrary-python-interface.md
• ../../laws/official-runtime-only.md

Official runtime boundary

Decision skill — does not render. Pins resolution + aspect; operator applies in scene render properties.

Operating procedure

1. Identify the consumer use case and all target delivery streams.
2. Pin the required aspect ratio (W:H) for each stream from the consumer spec (or mark fallback defaults as assumptions to confirm).
3. Pin the exact render resolution (W × H) and DPI / PPI (for print) to be set directly in scene render properties—do not prescribe post-render resizing, cropping, or upscaling.
4. For multi-aspect deliverables, define a separate resolution record per stream and hand off camera framing to camera-composition and composition-quality-checker.
5. Record caveats and set truth states to Runtime status: Not Run and Artifact status: Not Produced.

Decision tree

Consumer provides exact W × H (and DPI for print)?
  → Pin exact consumer spec; verify aspect ratio matches W × H.
Web / desktop widescreen placement?
  → Pin widescreen aspect (e.g., 16:9) and target display W × H from spec; DPI: N/A.
Social square placement?
  → Pin 1:1 aspect and platform-required W × H; DPI: N/A.
Mobile vertical / story placement?
  → Pin 9:16 aspect and platform-required W × H; DPI: N/A.
Ultrawide / cinematic banner?
  → Pin target banner aspect (e.g., 2.39:1) and spec W × H; DPI: N/A.
Print delivery (physical size + target DPI/PPI)?
  → Compute W × H = (physical inches × DPI) at exact print aspect ratio; pin W × H and DPI.
Multiple aspects required from one scene?
  → Emit one resolution record per stream; require per-aspect camera framing (never render-then-crop).

Playbooks

Playbook A: Single-stream digital hero

Pin the target aspect ratio (such as 16:9) and exact delivery W × H required by the placement spec (DPI / PPI: N/A). Operator enters W × H in scene render properties before composition check.

Playbook B: Multi-stream social campaign

Emit separate resolution records for each stream (for example, 9:16 vertical, 1:1 square, and 16:9 widescreen) with their respective target W × H. Hand off to camera-composition and composition-quality-checker so each aspect is properly framed in-camera rather than cropped post-render.

Playbook C: Print deliverable

Obtain physical print dimensions and required print density (DPI / PPI). Calculate exact pixel dimensions (W × H), pin the native print aspect ratio, and require rendering directly at final print resolution without post-render upscaling.

Playbook D: Multi-size asset family

When a consumer needs multiple distinct pixel dimensions, list each required W × H stream in the per-stream resolution record so the operator can plan native render outputs or hand off post-render image processing outside BlendOps.

Mode handling

Text-only mode

Return the resolution record, per-stream rules, caveats, and truth states (Runtime status: Not Run, Artifact status: Not Produced).

Runtime-ready mode

Return the exact same resolution record and truth states (Runtime status: Not Run, Artifact status: Not Produced) for the operator to apply in scene render properties. Actual file verification after rendering belongs strictly to render-export-evidence.

Blocked runtime mode

Return the resolution record, caveats, and truth states (Runtime status: Not Run, Artifact status: Not Produced).

Validation checklist

• Aspect ratio (W:H) explicitly pinned for every output stream
• Render resolution (W × H) explicitly pinned for every output stream
• DPI / PPI specified for print outputs (or marked N/A for screen)
• No post-render resize, crop, or upscale steps prescribed
• Caveats and downgrade-only truth states (Not Run / Not Produced) included

Pass / Warn / Fail rubric

Failure handling

• Consumer spec unspecified → ask once for placement and target dimensions; if unavailable, state a fallback aspect and W × H explicitly as an unconfirmed assumption in Caveats.
• Multi-aspect request → emit separate per-stream resolution records and route framing to camera-composition and composition-quality-checker (never advise silent cropping).
• Resolution exceeds hardware memory or render time budget → flag in Caveats and recommend operator review before rendering.

Troubleshooting

Best practices

• Always pin the delivery aspect ratio before camera setup so camera-composition and composition-quality-checker frame against the true boundary.
• Render directly at the required delivery resolution (W × H); keep post-render resizing, cropping, or format conversion outside this skill.
• For multi-aspect deliverables, output explicit per-stream records and require per-aspect camera validation.
• Pass the pinned resolution record to render-export-evidence so rendered files can be checked against target dimensions after execution.

Good examples

• "Consumer: Web hero. Aspect: 16:9. Resolution: 1920 × 1080 (per client spec). DPI/PPI: N/A. Multi-stream: none. Caveats: confirm whether high-DPI display tier requires a second native render stream. Runtime status: Not Run, Artifact status: Not Produced."

Bad examples

• "1080p." — no aspect.

User-facing response template

Consumer use case: <web hero / social / print / app asset / banner>
Aspect ratio: <W:H>
Resolution: <W H px ×>
DPI / PPI: <value if print, else "N/A">

Per-stream outputs (if multiple):
  - <stream name>: <W:H>, <W H px ×>, DPI/PPI: <value or N/A>

Caveats: <budget notes, unconfirmed spec assumptions>
Runtime status: Not Run
Artifact status: Not Produced
Evidence used: <consumer spec or "none">
Limitations: <known gaps>
Next: camera-composition -> composition-quality-checker -> render-export-evidence

Anti-patterns

• "1080p" without aspect.
• Render small, upscale large.
• Crop instead of re-frame for different aspects.
• "Default size" answers.

Cross-skill handoff

• [upstream_reference] Camera & composition planning (upstream framing setup) → ../camera-composition/SKILL.md
• [progression] Composition framing validation against pinned aspect → ../composition-quality-checker/SKILL.md
• [upstream_reference] Color configuration decision → ../color-management-decision/SKILL.md
• [progression] Container / codec decision → ../output-format-decision/SKILL.md
• [progression] Render engine decision → ../cycles-vs-eevee-decision/SKILL.md
• [progression] Post-render saved file verification → ../render-export-evidence/SKILL.md

Non-goals

• Never execute Blender or trigger renders.
• Never resize, crop, upscale, or convert images post-render (belongs outside this skill).
• Never choose file containers, codecs, or bit depths (output-format-decision).
• Never configure color spaces or HDR view transforms (color-management-decision).
• Never validate camera composition (composition-quality-checker) or verify rendered output files (render-export-evidence).

References

• references/aspect-defaults.md
• references/resolution-defaults.md
• references/print-vs-screen-rules.md
• ../../docs/skill-system.md