Documentation

Metropolygonia documentation

Build deliberately. Export with context.

These ten guides cover the path from design method and parameters to a usable 3D asset. Start with one building, understand what each format carries, then validate the result in the tool where final production happens.

Documentation index updated: 25 August 2026

GeneratorRule-driven geometry, explicit controls and repeatable seeds
OutputsGLB, glTF, OBJ, STL and organised city ZIP packages
PipelineUnreal Engine and general-purpose DCC handoff
MaterialsNamed groups, image textures and a 2 × 2 m UV convention

Start here

Five foundation guides, one practical path

01 / Quick start

Create your first procedural building

Set the envelope, refine the systems, choose interior detail and check the generated model before your first export.

02 / Pipeline

Export to Unreal Engine

Use GLB or a city package, import at predictable scale and validate materials, UVs and geometry before scene-wide use.

03 / Materials

Use the 2 × 2 m UV convention

Understand the base tile, adjust material scale and apply Megascans or other tiled PBR libraries without a complete re-unwrap.

04 / Reference

Choose an export format

Compare what GLB, glTF, OBJ and STL preserve, what they omit and when a city ZIP is the more manageable handoff.

05 / City

Create and export a procedural city

Save reusable buildings, draw roads and roundabouts, work with terrain, inspect manifest v3 and validate complete or incremental packages.

Design and scale

Five focused guides for deeper decisions

06 / Game development

Use procedural buildings in games

Decide where controlled variation helps, preserve the editable source and separate generated geometry from engine-specific runtime work.

07 / Concepts

Compare procedural, parametric and generative design

Use precise definitions to choose a method by control, repeatability, search space and verification needs.

08 / Architecture

Design roofs and facades

Work from silhouette to detail with seven roof families, corner controls, arcades, dormers and facade rhythm.

09 / Reproducibility

Manage seeds and building variants

Record project JSON, seeds, version context and handoff settings so approved variants remain rebuildable.

10 / Large scenes

Understand chunks and floating origins

Reconstruct full or incremental city packages from local geometry, stable resource paths and manifest v3.

Quick start

The reliable first ten minutes

Open the building editor
Start with a building rather than a city. A single asset is faster to inspect and makes scale or material problems easier to isolate.
Set real dimensions first
Choose the footprint, storey height and floor count before adjusting decorative systems. Those values control the fundamental volume.
Decide whether you need interiors
Generate rooms and circulation for a walkthrough, or use an exterior shell when the asset will remain context or background geometry.
Save the parameters
Keep the preset and seed for any option you may need again. Procedural variation is valuable precisely because it remains reproducible.
Export and validate one file
GLB is the recommended first test for Unreal Engine. Check a known dimension, UV orientation and material slots before repeating the process at city scale.

The generated model is an upstream asset

Finish project-specific materials, collision, lighting, simulation, topology cleanup and performance work in Unreal Engine or your chosen DCC tool.

At a glance

What each output is for

Output	Best first use	Important boundary
GLB	Compact handoff to Unreal Engine or another modern 3D tool.	Validate how the destination maps imported materials in your current version.
glTF	Open exchange where separate resources and inspectability are useful.	Move the scene description, binary data and images together.
OBJ + MTL	Broad compatibility and an intermediate DCC cleanup step.	Material semantics are simpler and files remain linked sidecars.
STL	Material-free geometry, proxies, collision or rapid prototyping.	It does not carry the UV and material workflow.
City ZIP	Separate buildings, road geometry and a manifest for a larger layout.	Import one representative asset before processing the full package.

Product state

What is ready and what is still in progress

The generator currently creates browser-based parametric building and city geometry, supports saved parameter workflows, and exports individual buildings as GLB, glTF, OBJ or STL. City projects can be packaged with separate buildings, road geometry and a manifest.

UV coordinates use a consistent 2 × 2 metre base convention, and supported model exports carry generated image textures and available PBR channels. Refine the final physically based material graph in the destination tool when the project needs engine-specific optimisation.

Metropolygonia is not a BIM, engineering or code-compliance product. Dimensions help maintain a predictable 3D scale; they do not certify that a generated building is constructible, accessible or compliant with local regulations.

Terms

Small glossary

Procedural generation: Geometry assembled by programmed rules from explicit inputs. In this product it is not generative AI.
Seed: A value that makes controlled variation repeatable when the other parameters stay the same.
UV coordinates: Two-dimensional coordinates that tell a 3D surface how an image or tiled material should be mapped.
Material group or slot: A named assignment on the model that lets the destination tool target groups of surfaces with a material.
City package: A ZIP handoff containing separately manageable assets instead of only one merged city mesh.