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name: rendering-viewer-assets description: "Choose and troubleshoot dm_control rendering backends, viewers, pixel observations, camera APIs, and optional Blender exporter workflows." metadata: disco-role: operating disable-model-invocation: true license: Apache 2.0

rendering-viewer-assets

Use this sub-skill when a task needs dm_control offscreen rendering, pixel observations, camera control, the interactive viewer, or safe guidance for the optional Blender MuJoCo exporter.

Do not use this sub-skill for non-rendering Control Suite rollouts; route those to ../suite-rl-workflows/SKILL.md. Route raw MJCF/MuJoCo model construction to ../mjcf-mujoco-models/SKILL.md, and custom Composer environment/task lifecycle work to ../composer-environments/SKILL.md.

First decisions

1. Identify the rendering target:
   • Offscreen RGB/depth/segmentation arrays: use physics.render(...) and probe MUJOCO_GL before building the workflow.
   • RL pixel observations: validate a backend first, then wrap with dm_control.suite.wrappers.pixels.Wrapper.
   • Interactive window: use dm_control.viewer.launch(...); it requires GLFW and a real display.
   • Blender export: treat as optional, external-Blender, documentation-only unless the user explicitly accepts Blender add-on installation risks.
2. Choose a backend before importing dm_control rendering modules. If MUJOCO_GL is unset, dm_control tries GLFW, then EGL, then OSMesa. Explicit values are glfw, egl, and osmesa; EGL also accepts MUJOCO_EGL_DEVICE_ID for selecting a GPU device.
3. Do not promise that every backend is installed. During construction, a headless EGL render probe passed, OSMesa failed because the OSMesa/OpenGL library was missing or unusable, and GLFW failed in a display-less headless session.
4. Install public packages only: use pip install dm_control for released packages, or pip install git+https://github.com/google-deepmind/dm_control.git for unreleased source snapshots. Editable installs are not supported by dm_control.

Bundled operating files

• Read references/rendering-viewer-reference.md when choosing a backend, calling physics.render, adding pixel observations, or adapting a viewer launcher.
• Read references/blender-exporter-reference.md when a user asks about exporting Blender assets to MuJoCo/MJCF, or before deciding that Blender work should be avoided.
• Read references/troubleshooting.md when rendering, PyOpenGL, pixel-wrapper, viewer, EGL/OSMesa/GLFW, or Blender add-on errors appear.
• Run scripts/render_backend_probe.py in a fresh Python process to test default, egl, osmesa, or glfw with a tiny installed-package render.
• Run scripts/viewer_launch_template.py as a safe dry-run template for suite or manipulation viewer launchers; it opens a GUI only when --launch is explicitly supplied.

Minimal operating pattern

python scripts/render_backend_probe.py --backend egl --height 48 --width 64

If the probe succeeds, use the same backend selection for the downstream render/pixel-observation process. If it fails, follow the failure-specific route in references/troubleshooting.md instead of changing unrelated suite, MJCF, or Composer logic.