pi-exr-reader

Pi extension that lets any pi session read .exr files — something pi's read tool can't do.

The exr_read tool reports:

• Part metadata — size, data window, storage, line order, compression, for every part of a multilayer EXR
• Per-channel statistics — min / max / mean / nonzero fraction, per component (UV_Box.R, st.G, ...)
• Exact float pixel values at a point, full precision
• Rect statistics over an inclusive region
• PNG preview — 8-bit linear-mapped (or viewer-look tone-mapped) image attached to the tool result when the active model accepts image input

Built for Arnold multi-AOV renders and UV/ST map inspection, but works on any EXR: scanline or tiled, any compression, multilayer or single-layer.

Install

pi install npm:pi-exr-reader

or from a local clone:

pi install /path/to/this/folder

Requirements

The extension shells out to a Python probe (exr_reader/exr_probe.py) using OpenEXR 3.x, numpy, and Pillow:

pip install OpenEXR numpy Pillow

The extension probes python / python3 and fails with an install hint if the packages are missing.

Usage

Ask your model to inspect an EXR, e.g. "what are the UV values at pixel (540, 540) in render.exr". Coordinates are (x, y) with origin at the top-left of the data window, y increasing down — matching the preview PNG orientation.

Channel names are case-insensitive; a group name selects all its components ("uv_box" → UV_Box.R/.G/.B).

Development

Source lives in exr_reader/ (index.ts + exr_probe.py). No build step — pi loads the TypeScript directly. The production global install on the author's machine is a copy at ~/.pi/agent/extensions/exr_reader/; re-copy after changes (or pi -e <this folder> to test from source).