render request: ALSO pin appearance (texture + lighting), not just the camera rig

render_request/README.md

@@ -37,6 +37,27 @@ is constant across frames (it should be rigid — ours measures a per-element st
 
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+## 1b. Appearance must be PINNED — this is new, and it matters more than the rig
+
+The existing demos are **appearance-randomized per demo**: the render pipeline runs
+`TextureModder` and `LightingModder` off a per-attempt `variant_seed`, so each of a task's 20
+demonstrations has a different table material, a different floor and different lighting. We only
+found this by looking at the frames — it is recorded in the render manifest, not in the task's
+`domain_randomization` block, which contains position deltas only.
+
+For a 20-demo benchmark that is a problem. The policy has to learn appearance-invariance *and* the
+manipulation skill from 20 samples, so the score conflates two abilities and cannot be attributed
+to the one under test. Measured on the current demos: a reach task scores 82% while two
+manipulation tasks score 2% and 0%, with 99 of 100 rollouts running to the step cap — acting, never
+completing.
+
+**So please render all 20 demos of a task under ONE fixed appearance:** one table material, one
+floor, one lighting setup, held constant across every demo and every task. Concretely, either
+disable `TextureModder` and `LightingModder`, or hold `variant_seed` constant across the batch.
+
+If your pipeline cannot pin them, please say so rather than varying them — we would rather know and
+design around it than discover it in the frames again.
+
 ## 2. What to render
 
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