Material graphs

A material is a network of nodes: constants, parameters, math, texture samples and outputs. It is stored in a binary .uasset that you normally read in the Material Editor. MGIR writes that network out as short, line-based text, with every node, connection and property value. Your assistant reads it and writes edited text back into the material.

What it gives you

Diffable in version control

A recolor or a rewired output becomes a few changed lines in a pull request. Reviewers don't have to open the editor to see it.

Reviewable like code

You read the whole graph top to bottom: which constant feeds which output, and which parameters exist. You can check an edit to a material the same way you check a code change.

Easy for your assistant to write

One consistent format, with nodes named by their full Unreal class path. Your assistant reads the whole graph, edits a few lines and writes it back, instead of wiring nodes one at a time.

What carries over

Reading is stable, and the same text appears in asset dumps as mgir.txt. Nodes, connections, property values and authored @(x, y) positions carry over. Editor cosmetics do not.

What the text looks like

The first line names the material. Each node gets a %name, an optional @(x, y) sets its position, and output lines connect values to the material's pins:

entry material `/Game/Materials/M_Rim` {
    %tint = constant Float3(0.2, 0.4, 1.0) @(0, 0)
    %fres = call `/Script/Engine.MaterialExpressionFresnel`() @(200, 0)
    output BaseColor: %tint
    output EmissiveColor: %fres
}

Nodes use full class paths (call `/Script/Engine.MaterialExpressionAdd`()). Short aliases are rejected, so the text always has one meaning. When the Substrate shorthand is on, common Substrate nodes show in a shorter form such as %front = slab(DiffuseAlbedo: %albedo).

How to ask for it

Ask for the change in plain words. Your assistant reads the material as text, edits it, and writes it back. You never need to write the syntax yourself. More examples are on the Materials page.

You: In M_Rim, make the rim tint green instead of blue.

Done. The rim tint in M_Rim is now green.