resolution-aspect-decision

name	resolution-aspect-decision
description	Pick the right render resolution + aspect ratio for the consumer use case before render; avoid render-then-crop and aspect mismatch.

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

• name the consumer + intended placement (hero / social / print / app)
• pick aspect ratio (16:9 / 1:1 / 9:16 / 2.39:1 / 4:5)
• pick resolution (consumer required × 1.5 for downscale-quality margin if going to be resized)
• pin

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)
• pure modeling
• internal preview-only renders (any reasonable size works)

Trigger phrases

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

Prerequisites / readiness

• consumer use case known
• color management + format chosen (other decisions)

Input schema

Required inputs

Input	Why it is required
Consumer use case	Drives aspect + resolution
Format choice	Affects max practical resolution

Optional inputs

Input	Use
Brand spec	Override if specified
Multi-resolution requirement	Generate per-tier outputs

Assumptions to confirm

• The render machine can handle the chosen resolution (memory).
• Time budget allows the chosen resolution + samples.

Output schema

Primary output

A 3-line resolution record: aspect, resolution (W × H), DPI / PPI if print.

Secondary output

• per-output stream resolution if multiple outputs
• caveats

Evidence / caveat output

Runtime status: Not Run | Attempted | Produced | Verified | Failed | Blocked / Not Run
Artifact status: Not Run | Not Produced | Produced | Verified | Failed
Evidence used: <links, paths, logs, or "none">
Limitations: <known gaps>

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 consumer use case.
2. Read aspect from consumer spec or default per references/aspect-defaults.md.
3. Read resolution from consumer spec or default per references/resolution-defaults.md.
4. Apply downscale margin (1.5x) if downstream resize is expected.
5. Pin DPI for print outputs.
6. List caveats.

Decision tree

Web hero?
  → 16:9, 1920×1080 (or 2880×1620 for retina)
Square social?
  → 1:1, 2160×2160 (or 1080×1080 for old IG)
Mobile portrait?
  → 9:16, 1080×1920 (or 1440×2560 for high-DPI)
Cinematic banner?
  → 2.39:1, 2560×1080 (or 3840×1620 for 4K-banner)
Print A4 portrait?
  → 4:5 effective, 2480×3508 at 300 DPI
Print A4 landscape?
  → 5:4 effective, 3508×2480 at 300 DPI
Print A3?
  → 3508×4961 at 300 DPI
HDR display delivery?
  → Same as web; verify HDR pipeline

Playbooks

Playbook A: Web hero

16:9, 1920×1080 standard or 2880×1620 retina. Render once at retina; downscale for standard.

Playbook B: Multi-format social

Portrait 9:16 1080×1920 + Square 1:1 1080×1080 + Wide 16:9 1920×1080 — render scene once at largest, crop / re-frame for others (or re-render with adjusted camera).

Playbook C: Print poster A2

Final 5060×7160 at 300 DPI; render at this directly; do not upscale a smaller render.

Playbook D: App icon

1024×1024 at 1:1; export multi-resolution downscales (256, 128, 64, 32) post-render.

Mode handling

Text-only mode

Resolution record only.

Runtime-ready mode

After render, verify file dimensions match.

Blocked runtime mode

Resolution record only.

Validation checklist

• Aspect ratio chosen
• Resolution (W × H) chosen
• DPI / PPI for print
• Downscale margin if applicable
• Caveats listed

Pass / Warn / Fail rubric

Verdict	Criteria
Pass	Aspect + resolution + DPI explicit; matches consumer; downscale margin if needed.
Warn	Aspect set but resolution borderline (just-below recommended for use case).
Fail	Aspect mismatched (rendering 1:1 for 16:9 consumer); upscaling small renders to large delivery.

Failure handling

• Consumer unspecified → ask once; default to 16:9 1920×1080 web.
• Multi-format → render once at largest aspect; re-render or crop for others (document choice).
• Memory / time exceeds budget at chosen res → escalate to render queue or reduce.

Troubleshooting

Problem	Response
Final delivery looks soft	Probably upscaled from low-res; re-render at delivery res.
Aspect cropped wrong	Pre-render at correct aspect; do not crop.
Print too low-DPI	Render at delivery DPI from the start; do not upscale.
Consumer spec unclear	Ask once, then default per consumer category.

Best practices

• Render at the delivery aspect, not at "standard 16:9 then crop".
• 1.5x downscale margin only if you know downstream will resize; otherwise render at delivery exactly.
• For multi-format, plan camera animation or re-frame; do not just crop.
• Document res in render evidence.

Good examples

• "Web hero. Aspect 16:9. Resolution 2880×1620 (retina). Downstream resize to 1920×1080 (standard) and 960×540 (mobile). Render once at retina; ImageMagick downscale post."

Bad examples

• "1080p." — no aspect.

User-facing response template

Consumer use case: <web hero / social / print / app icon / banner>
Aspect ratio: <ratio>
Resolution: <W × H>
DPI / PPI: <value if print, else "N/A">
Downscale margin: <yes 1.5x / no>

Multi-resolution outputs (if any):
  <output>: <W × H>

Caveats: <list>
Limitations: <gaps>
Next: 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

• Color management → ../color-management-decision/SKILL.md
• Format → ../output-format-decision/SKILL.md
• Engine → ../cycles-vs-eevee-decision/SKILL.md
• Composition → ../composition-quality-checker/SKILL.md
• Render evidence → ../render-export-evidence/SKILL.md

Non-goals

• Resize / upscale post-render.
• Run Blender.
• Calibrate display.

References

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