A three.js pass that redraws the scene through overrideMaterial sees the raw vertex attributes, not what each mesh's own shader does

Fact

With scene.overrideMaterial set, every mesh is drawn with the override's own vertex and fragment shaders. Whatever a mesh's ShaderMaterial did is skipped:

• No normal attribute (custom shaders often light from their own data): the override reads a zero normal, which normalizes to NaN.
• Positions moved in the vertex shader (instance offsets in a custom attribute, wind sway, packed coordinates) are drawn at the raw position.
• Alpha-blended or alpha-tested cards (blob shadows, decals, foliage) become solid quads, since the override ignores their maps and transparency.

GTAOPass (when it renders its own G-buffer), SSAOPass, SAOPass, BokehPass and OutlinePass all build their normal, depth or mask buffers this way.

Why it matters

The damage lands far from the cause. A voxel terrain with no normals turned the whole ground and sky black under GTAO (the NaN goes through the blend), while the ordinary models looked fine — it reads as a broken pass, not as missing data.

How to apply

• Feed the pass the main render's depth instead of letting it re-render: render into a target with a DepthTexture, then gtao.setGBuffer(depth); normals are reconstructed from depth, so every shader's own placement counts.
• In r186, passing depthTexture to the GTAOPass constructor throws; construct it without and call setGBuffer afterwards (fixed in r187).
• To check a pass, show its intermediate buffer (gtao.output = GTAOPass.OUTPUT.Normal) and look for black or missing regions.