Does Maya's Viewport 2.0 release GPU memory when nodes are deleted via script?

Direct Answer

No — deleting nodes via script (cmds.delete()) removes them from the scene graph, but Viewport 2.0 does not immediately free the associated GPU buffers. The memory stays allocated until the viewport is explicitly refreshed or the view panel is redrawn.

Confirmed Behavior

• Node deletion (cmds.delete(nodes)) purges the DAG nodes from the scene.
• GPU buffers (geometry, textures, render targets) remain cached inside ViewportRenderUtil after deletion.
• Memory is released when you trigger a viewport refresh — e.g., cmds.refresh(suspend=False), modelEditor -e -refresh true, or by closing and reopening the model panel.

Likely Explanation

ViewportRenderUtil maintains a resource cache for performance. When a node is deleted, the cache entries are not automatically invalidated; they persist until the next draw cycle or an explicit refresh forces a cache purge. This design avoids the overhead of per-deletion GPU deallocations during interactive editing.

Script Job Complication

Python script jobs that hold references to deleted nodes (or to temporary objects created during the deletion) can keep the internal caches alive longer, because the garbage collector cannot reclaim objects that are still referenced. The symptom is a gradual GPU memory climb during long‑running scripted sessions.

Version Assumptions

Observed across Maya 2018–2024. Some point releases purge caches more aggressively on delete, but the general pattern — release on refresh — holds throughout the range.

Minimal Verification Steps

1. Open a clean scene with a moderately complex mesh (e.g., 500k triangles).
2. Record baseline GPU memory: nvidia-smi or Maya’s memInfo command.
3. Run cmds.delete(selected_nodes) via Python.
4. Immediately re‑measure GPU memory — it should be unchanged.
5. Trigger cmds.refresh(suspend=False) (or toggle the model panel’s refresh).
6. Re‑measure — a measurable drop confirms release on refresh.

One Diagnostic Detail That Changes the Recommendation

If you are running batch/headless Maya (no interactive viewport), the refresh path does not exist. In that mode, does the process eventually release GPU memory on its own, or does it require an explicit cmds.quit()? Confirming this determines whether a scheduled restart is needed for long batch runs.