Omniverse Realtime Viewer

Streaming vs Local Omniverse Realtime Viewer

Use this before choosing the app shell. Local lightweight, Tauri/Rust, Electron + SHM, and streaming paths can share USD stages, renderer concepts, storage resolution, camera math, selection logic, and query helpers, but they optimize for different users and deployments.

Focused viewer paths in this skill package separate lightweight viewers from the full-editor shell. If the user explicitly requires an editor shell with docking, undo, transform gizmos, and editor lifecycle, read ovwidgets-editor-shell.

Choose Tauri/Rust When

Use a Tauri 2.0 desktop app with Rust FFI to OVRTX when:

• The user runs on the GPU workstation but you need web-technology UI (React).

• No Python runtime dependency is acceptable.

• You want to share UI components or styling with the WebRTC streaming Omniverse Realtime Viewer.

• The target is a packaged desktop binary (.exe/.app) rather than a script.

• A ViewerBackend interface must be shared across local and web paths.

Architecture:

React WebView (Vite/Tauri)
  -> useTauriBackend.ts (ViewerBackend)
  -> Tauri IPC invoke / Channel
  -> Rust render thread
  -> ovrtx C FFI (step/map/write)
  -> CPU-mapped RGBA -> binary push to WebView

See skill: tauri-local-viewer

Choose Electron + SHM When

Use electron-shm-viewer when:

• The app runs locally on the GPU workstation.

• The renderer should stay in a separate Python process (not embedded in the UI process).

• The UI should be Electron + React, sharing components with streaming and Tauri frontends.

• Python is acceptable for the server, but should not run inside the UI process.

• You want raw local frames without WebRTC, video codecs, or network transport.

• The same JSON event_type/payload protocol as streaming is needed, but over IPC/local transport.

• The frontend uses useShmBackend behind the same ViewerBackend interface.

Architecture:

Electron React renderer
  -> useShmBackend.ts (ViewerBackend)
  -> Electron preload / IPC
  -> N-API C++ addon
  -> POSIX SHM (/dev/shm)
  -> Python ovrtx render server
  -> ovrtx renderer.step()

See skill: electron-shm-viewer

Choose Local Lightweight When

Use local-viewer when the user runs on the GPU workstation and wants a focused app:

• Full desktop interactivity without a network stack.

• Header, viewport, narrow sidebar, scene switching, picking, info display, and settings.

• Access through local monitor, Xvfb, VNC, or similar.

• One operator or developer workflow.

python -m local_app
  -> ovui standalone GLFW window
  -> ImageBridge/ImageWithProvider
  -> ovrtx renderer
  -> local GPU framebuffer

Full Editor Requests

Do not route full-editor requests to the lightweight local-viewer path.

For a focused Omniverse Realtime Viewer that needs inspector-style features, combine local-viewer with focused references:

• stage-hierarchy for the hierarchy tree and variants.

• prim-info-display for selected prim properties.

• selection-feedback and selection-animation for visual selection state.

• render-settings and viewport-overlays for controls and viewport UI.

Choose ovwidgets-editor-shell only when the requested experience truly needs full-editor capabilities:

• Built-in stage browser, property inspector, layer/content windows, selection outline, transform gizmos, camera inertia, and undo.

• Docking, shortcuts, themes, settings, status bar, and editor lifecycle.

Choose Streaming When

Use ovrtx + ovstream + WebRTC + React when the Omniverse Realtime Viewer must run remotely:

• Browser clients connect to a GPU host.

• Remote access, web UI, auth, routing, embedding, or service deployment matters.

• Input travels over the NVST native input channel; app state travels over the WebRTC data channel.

• Frames must be encoded/transported to another machine.

React/Vite frontend
  <-> WebRTC signaling/data/video
  <-> ovstream server
  <-> Python render loop
  <-> ovrtx renderer
  <-> CUDA/NVENC

Shared Pieces

• USD stage assets and composition patterns.

• ovrtx concepts: camera prims, render products, LdrColor, renderer.step(), and write_attribute().

• Optional S3-compatible asset sync to a local cache.

• Stage query logic, picking/highlight concepts, camera math, and transform-authoring conventions.

• GPU/display/headless environment setup, OVRTX_SKIP_USD_CHECK, and stale GPU process checks.

Differences

Decision Rule

When the user does not name a UI framework, default to a React-based shell. Choose streaming/WebRTC when browser access, remote GPU execution, embedding, or web deployment is plausible. Choose Tauri when the user clearly wants a packaged local desktop binary. Choose the lightweight ovui path only when Python, omni.ui, native local UI, or an in-process viewer is explicit.

Start streaming if the GPU is remote, the user must stay in a browser, or the Omniverse Realtime Viewer must integrate with a web product.

Start Tauri if the app runs on the GPU workstation, needs a web-tech UI (React), wants to share components with the streaming path, and should ship as a native binary without Python.

Start Electron + SHM for local GPU apps that need React/Electron UI, process isolation, Python ovrtx server, and raw local frames without WebRTC.

Start local lightweight (Python/ovui) for a focused viewer without editor affordances.

For full editor shell requests, use this skill only for preliminary routing. Then follow the full-editor guidance provided by the current ovui dependency guidance if it is available; otherwise state that this skill package does not define a full-editor implementation path.

Choose the renderer topology deliberately. A Tauri app should not bring in ovstream or ovui. An Electron SHM app should not bring in ovstream WebRTC, NVENC, or browser streaming unless it is also intentionally exposing a remote co-viewing stream. A streaming app should not depend on Tauri IPC. A local ovui app should not bring in WebRTC.

Input Path Contract

• WebRTC: use NVST's native input channel by default. Browser mouse, keyboard, wheel, and touch input reaches server.on_input as binary InputEvent structs. A browser JSON fallback is allowed only after viewer-input-routing verifies that native callbacks are absent while the data channel works; it must replace, not duplicate, native camera input.

• SHM: use ovstream.Client(ovstream.ClientType.SHM, stream_name="...").send_input_event(event) from Python, or ovstream_client_send_input_event(client, event) from C, to send InputEvent structs. Do not use JSON mouseInput for SHM camera control.

• In-process: call the Python/C++ camera, selection, and settings APIs directly from the local UI/event loop.

Read viewer-input-routing before implementing any path that handles camera gestures, click picking, viewport input ownership, or transport button ids.

Streaming Loop Skeleton

import os
os.environ.setdefault("OVRTX_SKIP_USD_CHECK", "1")
import ovrtx
ovrtx.register_schema_paths()
import ovstage
from ovstage import PopulationDomain, population

stage = ovstage.Stage("viewer")
# Populate the viewer-owned composite, wait, then publish ordinal 1.
population.open_usd_from_string(stage, composite_usda, ordinal=1, domains=PopulationDomain.RENDERING)
stage.advance_write_floor(1).wait()
renderer = ovrtx.Renderer(...)
renderer.attach_ovstage(stage)
server = ovstream.Server()
server.on_message = handle_message
server.on_input = handle_input
server.start(config)
while running:
    products = renderer.step(render_products={render_product}, delta_time=dt, ordinal=runtime.current_committed_ordinal)
    stream_ldr_color(products[render_product])  # helper maps/copies before returning

Keep shared code below the shell boundary: stage resolution, storage sync, USD metadata queries, camera math, and renderer setup. Keep UI state, input routing, and lifecycle in the chosen shell.

Gotchas

• Local import order: set OVRTX_SKIP_USD_CHECK=1, import ovrtx, call ovrtx.register_schema_paths(), then create/populate OVStage. Keep pxr behind the selected isolation boundary; do not let another OpenUSD consumer initialize before schema registration.

• Streaming import order can differ, especially when pxr is isolated in a worker.

• LdrColor casing is required in all paths.

• Browser media ports are negotiated by WebRTC; do not manually invent frontend media-port settings.

• Local frame readback may be hidden inside a widget; streaming must explicitly map/copy/encode frames.

• Tauri frame delivery is raw RGBA binary Channel push — no JPEG/base64 encoding.

• Kill stale Python GPU processes before diagnosing renderer hangs.

See also: tauri-local-viewer, local-viewer, dependencies, viewer-input-routing, streaming-client, streaming-server.