ThanhNguyxnOrg 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
- Identify consumer use case.
- Read aspect from consumer spec or default per
references/aspect-defaults.md. - Read resolution from consumer spec or default per
references/resolution-defaults.md. - Apply downscale margin (1.5x) if downstream resize is expected.
- Pin DPI for print outputs.
- 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.mdreferences/resolution-defaults.mdreferences/print-vs-screen-rules.md../../docs/skill-system.md