PBR Pipe Preview

A PBR_PIPE is a black box in the worst way: one wire, eight maps, zero visibility. When your material looks wrong, the first question is which map is wrong - and the wrong answer to that question is unlinking the pipe and digging through individual wires to inspect each map. PBR Pipe Preview exists to make that inspection one node: pipe in, all your maps out as a preview batch, and the pipe passes through untouched.

This is a debug node, and the pack treats it like one - the README lists it as the tool for "debug pipeline at any stage" and "quick visual check." Every serious pipeline has one of these, and it earns its place the moment a roughness map you were sure was fine turns out to be inverted noise.

How it works

Two outputs. pbr_pipe is the same pipe you fed in, passed straight through - so you can insert this node anywhere in the middle of a chain without changing the data flow. preview_batch is every map in the pipe collected into one image batch (in canonical order: albedo, normal, AO, height, roughness, metallic, transparency, emission; the v2.1 changelog notes emission is included in the preview). Wire that batch into a Preview Image node and you get a strip of every map, side by side, ready to eyeball.

If the pipe is empty or has only one map, it still returns something viewable, so it won't crash a graph mid-debug.

Installing it

Part of TextureAlchemy:

cd ComfyUI/custom_nodes
git clone https://github.com/amtarr/ComfyUI-TextureAlchemy

or via ComfyUI Manager (search "TextureAlchemy"), then restart. Under Texture Alchemist → Pipeline. No dependencies, no models.

How to use it without hating it

The trick is to put it where you can compare. Drop one Preview node right after your Combiner (what came in), and another after your Pipeline Adjuster (what came out), and the difference between the two preview strips tells you exactly which adjustment is wrecking your material. Because the pipe passes through, you can leave Preview nodes in place permanently at key stages - they're free, and they're the fastest way to answer "which map is this again?"

The one limitation worth knowing: it's a preview, not a diagnostic. It shows you the maps but won't tell you a normal is DirectX-flipped or a roughness is inverted - for that you eyeball the strip and reach for the pack's format validator or adjuster. But for the 90% case - "is my AO garbage?" - it's the node you want.