Proposal: DisplayXR for Foundry Nuke (3D in Nuke's own Viewer via the texture target; NDK node on the shared host core, Leia SR tested)

[joehillthunder]

3D in Nuke's own Viewer on the tested display (Leia SR) via DisplayXR. It's a Python package plus one NDK node (DisplayXRViewer) on the shared app-neutral host core, the same core as MotionBuilder (#2423) and Houdini (#2432), using the runtime v2.55+ texture target. The user's Nuke camera drives a true-geometry stereo rig; Nuke renders both eyes (ScanlineRender or ScanlineRender2), and the woven frame is drawn over the Viewer. Status text reads "3D active".

Code: joehillthunder/displayxr-nuke @ 0328270 (private, Apache-2.0 + NOTICE; internals in src/core/coupling.h). Tested on Nuke 17.1, Windows 11.

What it does

• DisplayXR menu, Start 3D through the selected camera. The rig is built around it: an eye camera with per-view lens and matrix, eye size = the 3D area's size.
• Viewer controls: depth −/+ in 25 % steps and Reset, an explicit opt-in above the comfort limit, and the glass distance (default: the camera's focal point).
• Gamepad: an XInput pad drives Nuke's camera while Nuke is in front.
• Send to Omniverse (USD): GeoExport wrapped in a Y-up, cm, /World layer.
• Image → 3D through GeoImport (see Proposal: generated 3D content in DisplayXR apps (image→3D asset bridge with comfort-budget placement) #2391).
• Fallbacks: the core's own 3D window on older runtimes, and a Write-node review mode for licence tiers that can't load NDK plug-ins.

Measured

• On the panel (runtime v2.55.0): seated viewer tracked (eyes 5.2 cm apart), rated "good 3D, comfortable".
  • Concurrency: Nuke and Maya (Proposal: DisplayXR for Autodesk Maya (in-viewport Viewport 2.0 plug-in, Leia SR tested) #2390) both showed 3D at once, each in texture mode inside its own viewport.
  • Responsiveness: no main-thread blocks over about 4 minutes of live 3D.
• Depth control: 100 % gives 0.42 % of panel width behind and 0 % in front (content 2.84–5.14 m, glass at 3 m). 50 % gives 0.21 %. 150 % stays at 100 % without the opt-in.
• Rig check in Nuke 17.1 (headless): 0 px on the glass, 40 px crossed in front, 22 px uncrossed behind (theory 40 / 22.5), in both of Nuke's 3D systems.
• Core self test (sim-display): −0.081 % / +0.111 %, against −0.074 / +0.12 % predicted.
• Eye pull: 0.42 s per 924×342 stereo pair; main-thread validate is a flat 83–89 ms per update.

What a shared host library would need

• The host core as is (dxrh_*). Nuke uses it byte-identical, with app names only in coupling.h.
• A documented "pull both eyes" pattern for node-graph hosts:
  • one input plus node_input per view, not split_input, which grew about 3× per update in Nuke 17.1;
  • validate and request on the main thread only;
  • a multithreaded, abort-aware pull;
  • eyes changed only after the previous pair's serial is acknowledged.
• The eye near plane at the app camera's near plane under the framing pull-back (Proposal: DisplayXR for Autodesk MotionBuilder (in its own viewer via the texture target; an in-process adapter on an app-neutral host core) #2423, XrCameraRigDXR: with an app-framed verticalFov wider than canvas-true, the eyes land far above the app camera and the frustum is entirely below the horizon #2422).
• A texture-target presenter for GL hosts (WGL_NV_DX_interop2), shared with MotionBuilder.
• The comfort budget in display info (Display info: publish the comfort budget (front/behind disparity limits), e.g. layout.comfort {front_frac, behind_frac} #2388).

Open

• UI lag while dragging with 3D on. A fix (eye pull below UI priority, no per-tick validate) is checked headless only.
• Measurement: no atlas disparity capture inside Nuke yet; the numbers above are the core's live readout.
• Not yet tried: a pad on the panel, running beside Omniverse's 3D viewer, and the USD export in USD Composer.
• The review mode for non-NDK licence tiers is untested.
• Linux / macOS: blocked (GL viewer; no display plug-in).

🤖 Generated with Claude Code

[joehillthunder]

Done (2026-10-28)

Hosting-readiness on the installed runtime v2.55.0 passes:

• Program Files runtime and active plug-in: id=leia-sr in the log; "3D active" in Nuke's Viewer.
• Depth control works, and Nuke quits cleanly with 3D on.
• The eyes now render on Nuke's own render threads.

Known issues:

• A sustained scripted 60 Hz camera drag can crash Nuke. This hasn't been seen in seated use.
• The 3D refreshes when a camera move stops, not during it.