docs: re-profile ALab and the Moana island at 0.5.0

[doubleailes]

Summary

Production-scene measurements refreshed at 4143c58 (0.5.0), on the 72-vCPU machine, 2026-10-05. Docs only.

ALab frame 1004 (docs/alab_profile.md)

• Render 3:20.7 → 23.4 s; the import is now 88% of the frame. Peak 33.2 → 28.7 GiB.
• Texture lookups are 43% of render thread time, down from 89%, at 1.57 µs per eval. Shading / Raytrace / Integrator is 48 / 40 / 11.
• 72 threads render 5.4× faster than 8, against 1.25×.
• Light and shadow links are now read (3 occluder classes). The four lgt_screenLights are dropped because their lightLink names no receiver in the composed stage. Occluded shadow rays: 96% → 82%.

Moana island (docs/moana_profile.md)

• The full default render (128 spp) takes 29.3 s, where the first profile took 5:24 at 4 spp. Peak 51.5 → 31.6 GiB, with displacement read.
• Still 90% traversal, at 17.7 µs per closest hit; the import is 91% of the frame.
• The distantPalm_key light links resolve as intended.
• 35 archive prototypes contribute no geometry. This is unchanged since 2026-10-02 and not investigated.

Ptex streaming on the island (docs/ptex_streaming.md)

• MIPSPACE=file streaming against preload, interleaved: resident 7.34 → 0.61 GiB, Load assets 1:33 → 28 s, peak 31.6 → 23.9 GiB.
• Render +1.8% / +3.2%, within noise; the whole run is 67 s shorter.

The first profiles are kept as dated history sections. The matching figures in openspec/specs/usd-scene-import/design.md and in the CRUST_PTEX_STREAM_MIPSPACE user docs are updated.

Not updated:

• The Moana sky-rig colour table is still marked stale.
• docs/light_sampling.md §3.12 has ALab's learned-vs-power comparison. It predates shadow links and probably needs re-measuring.
• openspec/changes/stream-ptex-by-default/proposal.md still quotes the old +1.2%.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FXGCHSpPr1joewseS5422u

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PR Summary by Qodo

Re-profile ALab and Moana production scenes at 0.5.0

📝 Documentation 🕐 40+ Minutes

AI Description

• Refresh ALab and Moana profiles to show current render, import, memory, and lighting behavior.
• Re-measure Moana Ptex streaming, including its memory savings and mip-level colour trade-off.
• Preserve earlier measurements as dated history and align the import design and user reference.

Diagram

graph TD
  ALab["ALab profile"] --> Design["Import design"] --> Reference["Environment reference"]
  Moana["Moana profile"] --> Ptex["Ptex benchmark"] --> Design
  Ptex --> Reference

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High-Level Assessment

Keep the detailed, dated measurements in the existing profiles and update the shorter design and user-facing summaries. A single central table could reduce repeated figures, but would make these established references less useful in place.

Files changed (5) +457 / -108

Documentation (5) +457 / -108

alab_profile.mdAdd the 0.5.0 ALab frame profile +199/-22

Add the 0.5.0 ALab frame profile

• Documents current frame timings, memory, render sections, thread scaling, and light and shadow links. Moves the first profile and its resulting fixes into a dated history section.

docs/alab_profile.md

moana_profile.mdAdd the 0.5.0 Moana island profile +178/-26

Add the 0.5.0 Moana island profile

• Records a full-default 128-spp run, including import and traversal costs, memory, displacement, light links, and unresolved geometry-free prototypes. Retains the original profile and subsequent measurements as dated history.

docs/moana_profile.md

ptex_streaming.mdRefresh the island Ptex streaming comparison +51/-36

Refresh the island Ptex streaming comparison

• Replaces the primary preload-versus-streaming figures with interleaved 0.5.0 measurements and retains the earlier result for comparison. Explains the reduced load time and memory, near-noise render cost, and stored-mip colour bias.

docs/ptex_streaming.md

design.mdAlign import design figures with the new profiles +28/-23

Align import design figures with the new profiles

• Updates the ALab, Moana, and Ptex streaming summaries with current timings, memory, and bottlenecks. Keeps earlier benchmark figures identified as historical measurements.

openspec/specs/usd-scene-import/design.md

environment-variables.mdUpdate Ptex file-mipspace memory figures +1/-1

Update Ptex file-mipspace memory figures

• Refreshes the Moana residency and peak-memory savings quoted for 'CRUST_PTEX_STREAM_MIPSPACE=file', while retaining the warning about its colour bias.

site/content/docs/reference/environment-variables.md