Segmentation AOV (FET011 Semantic Labels)#

Two tests, run as a pair.

Property	Value
Test names	`semantic_labels_seg_labelled`, `semantic_labels_seg_stripped`
Feature(s)	`FET_011_STANDARD` (>=0.2.0), `FET_011_RTX` (>=0.1.0)
Engine	Kit / Isaac Sim (>=6.0)
Test version	1.0.0

Summary#

semantic_labels_seg_labelled renders the RTX semantic-segmentation AOV of the asset as authored and measures the fraction of the frame that resolves to a semantic label.

semantic_labels_seg_stripped frames the same asset identically, removes every SemanticsLabelsAPI and deprecated SemanticsAPI schema from the label sources SL.001 recognises, and renders again. The buffer should come back blank.

What Pass Guarantees#

Together they show the asset’s labels are honored by the RTX segmentation pipeline, and that the segmentation comes from those labels rather than from scene setup or incidental geometry. The stripped test is what makes the first meaningful: a populated buffer alone could be produced by anything in frame.

Label format correctness is not re-checked here — the offline validator is authoritative for that. This pair checks that the labels render.

What It Checks#

Both tests load the asset, add a neutral room, add a dome light, auto-frame the camera with camera_padding 1.2, and settle for settle_frames 5 frames. Each then attaches a colorized semantic_segmentation annotator to the viewport’s existing render product and steps the orchestrator once with render_subframes 4.

semantic_labels_seg_labelled — segmented coverage must reach on_coverage_min, default 0.005. The threshold is low on purpose: a small prop framed with padding covers only a few percent, and the question is whether anything segments at all, not how large the object is.
semantic_labels_seg_stripped — after the strip, segmented coverage must fall to off_coverage_max or below, default 0.002. Not zero: AOV edge pixels and denoiser fringing leave a few stray samples.

Coverage is measured as the fraction of pixels outside the single most common colour, rather than against a known background colour, because the AOV’s colour assignment is not stable between runs.

The strip walks the sources SL.001 resolves a label from — the prim, its ancestors, its computed bound material and that material’s ancestors, and its GeomSubset children — so it removes exactly what the requirement counts, including a bound material living outside the asset subtree. It is applied in the session layer before the single orchestrator step, so no re-render is needed.

Execution Model#

The two tests run in separate engine sessions. Replicator’s orchestrator can be stepped only once per session; a second step ends the process regardless of what happens in between. Each test therefore gets a fresh session and steps exactly once, which is why the labelled and stripped measurements are two tests rather than one before/after test.

Metrics#

Metric	Test	Meaning
`semantic_labels_on_coverage`	labelled	fraction of the frame that segmented, as authored
`semantic_labels_labelled_passed`	labelled	1 when coverage reached `on_coverage_min`
`semantic_labels_off_coverage`	stripped	fraction that still segmented after the strip
`semantic_labels_stripped_prims`	stripped	number of prims the strip edited
`semantic_labels_stripped_passed`	stripped	1 when coverage fell to `off_coverage_max` or below

semantic_labels_seg_stripped skips, rather than fails, when the asset carries no semantics to strip; in that case the labelled test reports the same asset as unlabelled.

Evidence#

Each test attaches its segmentation frame: semantic_labels_semseg_labelled and semantic_labels_semseg_stripped. The labelled test also captures an RGB frame, semantic_labels_rgb.

Common Failure Modes#

Labelled coverage near zero. No resolvable label on the visible meshes, a schema applied with no authored value, or an Isaac Sim older than 6.0, which does not resolve SemanticsLabelsAPI in the segmentation pass. Check the asset is in frame.
Stripped coverage still high. Something other than the asset’s own labels is driving the segmentation: semantics on a material bound to the asset but authored outside its subtree, labels on other scene content, or a deprecated SemanticsAPI block left alongside the modern labels.