`pcg`

AI & gameplay Experimental

Author PCG graph assets: nodes, edges, and procedural-generation node families.

What it’s for

This namespace authors Unreal's Procedural Content Generation graphs (UPCGGraph assets): you create the graph, append nodes by their settings class, and wire pins together to form a working procedural pipeline. Your assistant reads the current node and edge structure as text, then writes changes back one node at a time.

Use it when you want to build or edit a PCG graph without clicking around the graph editor: adding a points source, a slope or noise filter, a self-pruning pass, or a reference to another graph as a subgraph. Nodes are addressed by their UPCGSettings subclass path (for example /Script/PCG.PCGCreatePointsSettings), and every node you add needs an explicit x/y position because there is no auto-layout on the per-node path.

For common node families there are typed convenience handlers, so you do not have to know each settings class's field layout: slope-to-density, spatial or attribute noise, subgraph references, and self-pruning each get a dedicated call with the right knobs. When you would rather work in bulk or read a whole graph as text, the sibling pcg.pcgir surface offers a text-IR and decompiler path instead of imperative per-node edits.

This area is experimental and still improving. Method names, node families, and parameters may change as it matures, and the typed helpers cover only the most common node classes so far.

Examples

Create a graph and add a points source

Start a fresh PCG graph and drop in a node that generates points.

You: Make a new PCG graph called PCG_Scatter under /Game/PCG and add a Create Points node.

  call("pcg.create_graph", {name:"PCG_Scatter", savePath:"/Game/PCG"})
    → {ok:true, path:"/Game/PCG/PCG_Scatter"}
  call("pcg.add_node", {graphPath:"/Game/PCG/PCG_Scatter",
        nodeClass:"/Script/PCG.PCGCreatePointsSettings", x:0, y:0})
    → {ok:true, node:"PCGCreatePointsSettings_0"}

Done. PCG_Scatter created with a Create Points node.

Wire two nodes together

Connect a node's output pin to the graph's output so the pipeline actually flows.

You: In PCG_Scatter, connect the Create Points node's Out pin into the graph output.

  call("pcg.inspect", {graphPath:"/Game/PCG/PCG_Scatter"})
    → {nodes:[...], edges:[]}
  call("pcg.connect_pins", {graphPath:"/Game/PCG/PCG_Scatter",
        fromNode:"PCGCreatePointsSettings_0", fromPin:"Out",
        toNode:"OutputNode", toPin:"In"})
    → {ok:true}

Done. Create Points Out wired to the graph output.

Add a spatial noise filter

Insert a noise node using the typed helper, with a Perlin type and a seed.

You: Add a Perlin spatial noise node to PCG_Scatter with seed 42.

  call("pcg.add_noise_filter", {graphPath:"/Game/PCG/PCG_Scatter",
        x:300, y:0, kind:"spatial", noiseType:"Perlin2D", seed:42})
    → {ok:true, node:"PCGSpatialNoiseSettings_0"}

Done. Perlin2D spatial noise node added with seed 42.

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