Proposal: Sketchfab in glasses-free 3D (the VR button today, a multi-model 3D wall next)

[joehillthunder]

What works today

In the DisplayXR Browser, Sketchfab's "View in VR" is offered (isSessionSupported('immersive-vr') = true). The browser converts the immersive session in the tab into a true stereo pair, and the panel shows the model in 3D. Nothing is installed, and Sketchfab needs no change.

Limits of that route

1. Always full panel. The in-place preference is ignored on the site, so it can't weave in a window beside other apps (displayxr-browser#204).
2. One model per session.
3. Too deep. The site sets the scale, so scans come out life-size. A test cube measured −0.64 % crossed in front, about 4.6× the 0.14 % front budget, and large scans overflow the frame.
4. No depth control reaches the session.

Next step: a "Sketchfab Wall" page (built, being finished)

• One inline-3D session with a grid of woven tiles, each its own model, through @displayxr/inline3d addModel. Each tile is fitted to the comfort budget and turns by drag.
• Models arrive through Sketchfab's official Download API with the viewer's own token. The token stays in the tab (sessionStorage) and goes only to api.sketchfab.com.
• Each model's glTF zip is repacked into a GLB in the page. The Khronos validator found 0 errors on a 64 MB test set.
• Every tile shows its credit and licence. Without a token, tiles show 2D thumbnails with credits.
• Status text reads "3D active".
• Page-side lessons:
  • the woven canvas must be bare, with no CSS background;
  • tile sizes must be reserved before thumbnails and captions load. Otherwise tiles smear on the panel.

Asks

1. In-place presentation: the browser's immersive conversion should honour in-place / windowed presentation, so WebXR sites can weave in a window (displayxr-browser#204).
2. Depth cap: a depth/scale cap for converted immersive sessions on the legacy rig.
3. Longer term: Sketchfab's own viewer could adopt the inline-3D API directly.

Pending

• A panel retest of the Wall page after the smear fix, with a seated viewer for depth. Measuring from the browser needs someone seated, because of leia-sr: no tracked viewer gives identical eyes, so on-panel depth can't be measured; add a measurement switch or document it #2384.
• Real downloads with an API token.
• A Chrome/Edge WebXR check.

🤖 Generated with Claude Code

[joehillthunder]

Final update (2026-10-28): the Sketchfab Wall works on the panel

Panel retest after the smear fix: passed. Tested on runtime v2.55.0 in the DisplayXR Browser on the tested display.

• One tile first, then the full wall. Two locally hosted CC0 models (a scanned marble bust and a 4K chess set) wove side by side in their own tiles on one page, with status "3D active".
• Clean stereo pairs in the atlas, with none of the earlier ghost trails or page text inside the tiles.
• Seated check: Pass.
• What fixed the smear (page side):
  • the woven canvas is unstyled, and the black sits on a wrapper behind it;
  • each tile's square, its caption and the status line have fixed sizes reserved before anything loads, so nothing reflows under a woven tile;
  • models stay still unless dragged.

Depth: the seated rating above is the result. The atlas couldn't give a number:

• the one-tile capture was taken with nobody seated, so both eyes were identical (leia-sr: no tracked viewer gives identical eyes, so on-panel depth can't be measured; add a measurement switch or document it #2384);
• on the full-wall capture, the chessboard's repeating squares defeat block matching.

The tiles use the SDK's comfort-budget fit, unlike the VR-button route (−0.64 %, about 4.6× the front budget).

Status of the asks: unchanged. In-place presentation and a depth cap for converted immersive sessions are tracked in displayxr-browser#204.

Still pending:

• Sketchfab-hosted models in 3D need a viewer's API token. Until then those tiles show 2D thumbnails with credits; the Download API → GLB repack path is validated offline.
• A Chrome/Edge WebXR check.

🤖 Generated with Claude Code