Last updated: January 7, 2026

Table of Contents

Introduction

iCity is a professional procedural city generation add-on for Blender, designed to create realistic urban environments using Blender's Geometry Nodes system. Whether you're working on architectural visualization, game development, film production, or any project requiring detailed cityscapes, iCity provides the tools to build complex urban environments efficiently.

This documentation provides a comprehensive reference for all features, properties, and workflows available in iCity.

General Overview

iCity is built around the principle of transforming complex urban design into a streamlined, procedural workflow. The system provides a logical pipeline where:

  • Roads define the city structure
  • Blocks are generated around these roads
  • Plots and building masses are created automatically
  • Landscapes and environment elements fill the gaps
  • Lighting, materials, and visual systems transform the output into a production-ready city

iCity relies heavily on Geometry Nodes for procedural logic, with Python tools handling workflow automation, cleanup, UI enhancements, and exporting. This combination allows the add-on to remain non-destructive, editable, and fast to iterate on.

The export system is designed to be seamless. iCity provides a background export mode that runs without interrupting the user's workflow and supports GLB, FBX, and USD outputs when needed.

Visual Experience and Rendering Quality

Beyond procedural logic, iCity places great emphasis on its visual experience. A city is more than geometry — it is atmosphere, mood, and realism. For that reason, iCity includes multiple visual subsystems:

Parallax Rooms

Buildings can display parallax interiors, giving depth and illumination without expensive geometry. This makes windows appear alive during both day and night.

Lighting System & Night Mode

iCity includes automatic lighting features such as window illumination, streetlights, color variation, and nighttime ambience. With a single toggle, the user can transform the entire city into a cinematic night scene.

Wet Ground Materials

Special procedural materials simulate wet pavement and reflective surfaces, enhancing realism in rainy, nighttime, or stylized cyberpunk scenes.

Optimized Assets

iCity uses a fully curated asset library, designed with consistent topology, optimized materials, and guaranteed compatibility. Custom external assets are not supported at this stage, ensuring stability, predictability, and performance.

Performance and Algorithms

Performance is a core pillar of iCity. A procedural city can easily reach millions of polygons, so the system is intentionally engineered around speed, efficiency, and logical data management.

Light Mode

A lightweight generation mode allows rapid previews, quick layout testing, large-scale prototypes, and iteration without delay. This mode avoids heavy geometry and detailed materials, updating significantly faster.

Optimized Algorithms

iCity's procedural logic is structured in layers: Roads → Blocks → Plots → Buildings → Environment. Each layer is computed efficiently, minimizing unnecessary recalculations.

Additional optimization techniques include:

  • Use of instancing
  • Modular GN structures
  • Isolated computation zones
  • Minimized node dependencies

Python Workflow Helpers

Python tools support Geometry Nodes by managing cleanup, UI logic, procedural baking when required, background export, and large-scale scene processing. This blend of GN + Python provides the best balance of speed and control.

Challenges and Future Work

iCity's development required solving several challenges related to how Blender handles large procedural systems.

Blender Limitations

Blender's node evaluation can become heavy when dealing with large road networks, dense buildings, and many instanced objects. Solution: A modular node structure with strict optimization rules, supported by Python-side tools to reduce strain on the node system.

Custom Assets Issue

Allowing arbitrary external assets introduces inconsistent topology, unpredictable GN behavior, dramatic performance drops, and broken procedural relationships.

Future Work — iCity2

The long-term plan includes iCity2, which will introduce faster algorithms, simplified workflows, improved visual logic, and enhanced performance on very large scenes.